Europe’s green insulation

Styrodur®C

Roof Insulation

1 Styrodur® C Thermal Insulation 3

2 Flat Roofs 4

2.1 Types of Flat Roofs/Definitions 6

3 Advantages of Inverted Flat Roofs 7

3.1 Advantages of Styrodur® C in Inverted Flat Roofs 9

4 Applications 11

4.1 Substructure 11

4.2 Roof Sealing 11

4.3 Roof Drainage 11

4.4 Thermal Insulation Layer 12

4.5 Protective Layer 12

5 Examples 13

5.1 Inverted Gravel Roofs 13

5.2 Duo Roofs 14

5.3 Plus Roofs 15

5.4 Green Roofs 16

5.5 Roof Terraces 24

5.6 Parking Decks 25

6 Technical data Styrodur® C 31

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1. Styrodur® C Thermal Insulation

Styrodur® C is BASF’s environmentally friendly, extru-ded polystyrene rigid foam. It is free of CFC, HCFC and HFC and makes an important contribution towards reducing emissions of carbon dioxide (CO2).

Due to its high compressive strength, low moisture absorption, long working life and its resistance to decay, Styrodur® C has become synonymous with XPS in Europe. The compressive strength is the main dis-tinction between the various Styrodur® C-types.

Effective thermal insulation with Styrodur® C reduces energy consumption with the result that the investment in thermal insulation can be recouped within a short period of time. It makes for healthy and comfortable living and protects the building from the effects of moisture as well as high and low temperature.

Styrodur® C is manufactured according to the require-ments of the European norm DIN EN 13 164 and its reaction to fire has been classified as Euro Class-E according to DIN EN 13501-1. It is subject to extensive assurance tests from “Wärmeschutz e.V.” and has been granted the approval no. Z-23.15-1481 from the “DIBt”, the Institute of the Federal and Länder Governments for a uniform fulfillment of technical tasks in the field of public law.

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2. Flat Roofs

Although, the style and with it the materials chosen for covering and sealing flat roof constructions have a high architectural significance, it is not only the crea-tive aspect that shapes the characteristics of a build-ing. Apart from the building‘s functionality, economical aspects as well as structural design play a big part in choosing the right style, shape and material for a roof. Regardless of any specific demands, flat roofs can meet the requirements of building physics and construction just as well as steep roofs do.

According to the current norms and regulations of ther-mal insulation, the composition of layers for flat roofs as well as for roofs with varying inclinations provide long-term reliable protection against the effects of weather. Therefore, the “security” of a roof does not depend on the water bearing structure’s grade of inclination but rather on how well the planning and execution comply with the special requirements of the construction.

As opposed to the conventional warm roof with its roof sealing above the thermal insulation, special insulation materials like BASF‘s Styrodur® C allow the constructor of a flat roof to “invert” the layers. With such inverted roofs being the number one choice of a growing number of planners, BASF‘s Styrodur® C makes for the ideal thermal insulation. This brochure gives all the neces-sary information about the planning and construction of inverted roofs and explains their advantages over conventional warm roofs.

The thermal insulation of inverted roofs is subject to high compressive stress caused by precipitable water, the soil of the roof‘s greening or the loads of traffic on parking decks or roof terraces. Therefore, it has to come with high resistance to moisture and decay. Since it is already stressed during the installation e. g. by con-struction workers and light machinery like wheelbarrows

and because it is installed directly below the covering or the ground, it needs to come with high compressive strength. Moreover, it has to provide solid and long-lasting thermal insulation to provide the actual functions of an inverted roof.

Styrodur® C is a strong and easy to handle material, that meets all of the requirements mentioned above. During the extrusion process of the thermal insulation boards, a clean, even and compressed foam membrane forms on the surface, which makes the boards resistant to the effects of weather. The boards have rabbet edges all around, so as to avoid the formation of cold bridges when they are conjoined.

Due to its diverse characteristics, Styrodur® C is extremely versatile, which is why BASF provides a cata-log of various types. Index 1 specifies the main differ-ences of all Styrodur® C types suitable for inverted roofs, the most important being compressive strength and thermal conductivity. The different types of Styrodur® C are specified in Index 2.

For inverted roof constructions according to the Ger-man DIN 4108-2 norm, choose the right l-value from Index 3. If the roof is to be designed as a green roof or inverted roof, you have to consider Approval number Z-23.4-222. Heat insulation has to be demonstrated fol-lowing the rated values of the DIBt-Approval, depending on the thickness of the thermal insulation (see Index 3).

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Fig. 1: Prestige object: For the reconstruction of the Water Tower in Hamburg, the roof is being insulated with Styrodur® C.

Fig. 2: Due to its high compressive strength and low thermal transmission coefficient Styrodur® C is the perfect choice for inverted flat roof constructions.

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lD = Thermal conductivity according to

DIN EN 13164

RD = Surface resistance according to

DIN EN 13164

l = Thermal conductivity according to

DIBt Approval No. Z-23.15-1481 in

accordance with DIN 4108-4

lB = According to DIBt Approval No. Z-23.4-222

for inverted roofs built as green roofs or

parking decks Z-23.4-222

Index 2: Types of Styrodur® C

Unit

3035 CS 4000 CS 5000 CS

Edge profile

Surface skin skin skin

Thickness mm T1 30/40/50/60/ 30/40/50/ 40/50/60/ 80/100/120/ 60/80/ 80/100 140/160/180 100/120

Length x width mm 1,265 x 615 1,265 x 615 1,265 x 615

Styrodur® C

Index 1: Technical data of Styrodur® C types for inverted roofs

Properties Unit Code according to DIN EN 13164 3035 CS 4000 CS 5000 CS Norm

Compressive strength or compressive kPa CS(10\Y) 300 500 700 DIN EN 826

stress at 10% deformatin

Permitted long-term compressive creep; 50 years kPa CC(2/1,5/50) 130 180 250 DIN EN 1606 compression < 2 %

Deformation behaviour 20 kPa; 80 °C % DLT(1)5 ≤ 5 ≤ 5 ≤ 5 DIN EN 1605

Deformation behaviour 40 kPa; 70 °C % DLT(2)5 ≤ 5 ≤ 5 ≤ 5 DIN EN 1605

Long term water absorption by immersion Vol. % WL(T)0.7 0.2 0.2 0.2 DIN EN 12087

Long term water absorption by diffusion* Vol. % WD(V)3 2 – 4 2 – 4 2 – 4 DIN EN 12088

Freeze-thaw-resistance Vol. % FT2 ≤ 1 ≤ 1 ≤ 1 DIN EN 12091

Styrodur® C

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Index 3: Thermal conductivity of Styrodur® C

lD [W/(m.K)] RD (m2.K/W) l [W/(m.K)] lB

20 0.032 0.65 0.033 -

30 0.032 0.95 0.033 -

40 0.034 1.25 0.035 0.037

50 0.034 1.50 0.035 0.037

60 0.034 1.80 0.035 0.037

80 0.036 2.30 0.037 0.039

100 0.038 2.80 0.039 0.040

120 0.038 3.20 0.039 0.040

140 0.038 3.65 0.039 0.040

160 0.038 4.20 0.039 0.040

180 0.040 4.45 0.041 0.042

Thickness (mm)

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2.1 Types of Flat Roofs

According to German DIN 18531 norm those roofs belonging to Inclination Group I (> 3°; 5 %) and Inclination Group II (between 3° and 5°; 5 % – 9 %) are defined as flat roofs. The inclination of the roof signifi-cantly influences the type and design of the chosen roof insulation. According to the guidelines of the German Roofing Contractors Association (ZVDH) depending on their construction roofs are being separated into venti-lated or non-ventilated/warm roofs. On non-ventilated flat roofs, all layers are installed directly on top of each other. If these layers are glued onto each other the con-struction is called a compact roof. Depending on their use, one distinguishes between “utilized” and “under-utilized” space.

Under-utilized space is only walked on for maintenance purposes. For the construction of under-utilized space see German DIN 18531 norm.

Utilized space is designed to be used by people and traffic as well as for intensive or extensive greening. The guidelines for flat roofs distinguish accordingly between:

Roof terraces, Parking decks, Green roofs (extensive or intensive)

For the construction of utilized spaces see GermanDIN 18195-5. According to guidelines for flat roofs polystyrene rigid foam insulation boards with average compressive strength should be used for under-utilized flat roofs, while for utilized flat roofs one should use rigid foam boards with high compressive strength. All Styrodur® C types usable for inverted roofs meetthose requirements according to Index 1 (page 5).

The old application requirements for applications of polystyrene rigid foam, which were constituted in the German DIN 18164-1 norm, (application type WD – compressive stress and application type WS – high compressive stress) have not been implemented in the new European DIN EN 13164 norm. Application require-ments for thermal insulation are specified in DIN V 4108-10 norm in which the inverted roof con-struction is classified as “DUK”. Minimum requirements concern: thickness tolerance, maximum permissible deformation for predefined compressive stress and temperature, compressive creep, water absorption by diffusion and freeze-thaw-resistance as well as the compressive strength at 10 % deformation for three categories a) dh (min. 300 kPa) for high compressive strength, b) ds (min. 500 kPa) for very high compres-sive strength and c) dx (min.700 kPa) for extremely high compressive strength. Depending on the position of the insulation layer, the unventilated roof is either known as a warm roof or an inverted roof. Both types can be constructed for utilized or under-utilized flat roofs. See the basic construction in Fig. 3.

Gravel Roof sealingGeotextile Thermal insulationStyrodur® C

Roof sealingVapor barrierReinforced concrete pavement

Warm roof Inverted roof

Fig. 3: Comparison between warm and inverted roof.

Types of Flat Roofs/Definitions

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A warm roof is a non-ventilated roof with a weather-proof roof sealing on top of the insulation layer.

However, there are three different types of inverted roofs:

The most common is the standard inverted roof with the thermal insulation layer being one layer of extruded polystyrene rigid foam, installed only on top of the roof sealing.

The so-called Duo roof has a second Styrodur® C insulation layer on top of the conventional warm roof and the roof sealing. This construction type is most common among new buildings. Depending on the

climatic conditions there is no need for a vapor barrier.

The Plus roof is a constructive solution for the recon-struction of flat roofs that are not sufficiently insu-lated. It is also an option if the advantages of a warm roof are to be combined with those of an inverted roof. In these cases an inverted roof with XPS insula-tion boards is installed on top of the warm roof con-struction e. g. with EPS insulation in order to protect the roof and expand its durability. More precisely, a thermal insulation layer from Styrodur® C is sub-sequently installed on top of an existing warm roof construction whose roof sealing has previously been checked for its functionality.

All three types are an option for graveled roofs, roof terraces, green roofs or parking decks. While the constructional applications are modified, the principle inverted roof construction remains unaltered. According to the German DIN 4108-2 norm, the inverted roof construction is applicable for graveled roofs as well as for roof terraces. Only green roof and parking deck constructions need approval from building authorities which exists for Styrodur® C (DIBt approval no. Z-23.4-222).

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Fig. 4: Prestige object: Office building close to the Hongkong Airport with Styrodur® C.

Types of Flat Roofs/Definitions

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3. Advantages of Inverted Flat Roofs

An inverted flat roof consists of the following layers:

Protective layer (e. g. gravel) Geotextile (optionally) e. g. polyester or

polypropylene mat Styrodur® C insulation layer Roof sealing functioning as a vapor barrier Leveling course Reinforced concrete pavement

The inverted roof is easier and quicker to install than a regular warm roof because it consists of fewer layers that have to be laid and glued.

On an inverted roof the sealing, a very important layer, is installed directly on top of a solid, massive under-ground that has to be free of grooves, with the excep-tion being the plus roof and the duo roof. In case of mechanical strain, the sealing can directly transfer the occurring stress. However, if an insulation layer is installed, little grooves can form in between the various layers of insulation boards and the sealing could “lag” in those grooves, which could lead to cracks.

However, if the sealing is glued onto the complete sur-face of a massive concrete pavement, any potential leakages could be detected easily. The water will leak from exactly that spot of the inside surface where the sealing is damaged. Not so in case of a conventional warm roof: If the water leaks through the sealing the vis-ible damage caused by the water will appear far from the permeable area.

There must also be absolutely no moisture between the vapor barrier and the roof sealing which can be difficult to realize. When installing a warm roof, it is important that the thermal insulation boards stored on the con-struction site are protected from humidity at all times and that the installed boards are covered.

As a rule, the insulation boards are not to be installed in rain or fog or the embedded moisture below the roof sealing will cause steam bubbles. However, when con-structing an inverted roof, the insulation boards can also be installed in the rain. The water can simply dif-fuse through the Styrodur® C thermal insulation layer or evaporate through the butt join into the surrounding air.

The vapor sealing of inverted roof constructions should have a water vapor transmission layer that is at least 100 mm thick to reduce the water vapor diffusion through the roof construction while at the same time keeping the transmission from changing direction during the summer and letting moisture inside the building.

Because the roof sealing of an inverted roof is installed below the thermal insulation layer and the covering (e. g. gravel or pavement) it is permanently protected from ultraviolet rays. Depending on the structure, the roof sealing of conventional warm roofs could be exposed directly to the sun’s UV-rays, which can cause damages in bituminous as well as plastic sealing con-structions.

Also, the thermal fluctuations of the roof sealing are less significant in inverted roof constructions. Thermal fluctuation upon the membrane can be up to 110 K dur-ing the cause of one year in the case of a conventional warm roof while it only reaches 12 K in inverted roof constructions with room temperatures of 20 ºC below the roof.

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Fig. 5 illustrates the everyday strain of thermal fluctua-tions of the roof sealing within a conventional warm roof construction without gravel, as opposed to an inverted flat roof. During the summer, temperatures on the warm roof sealing can rise up to 70 ºC whereas temperatures are nearly stable if an insulating layer protects the roof sealing, as is the case with an inverted roof. Thermal shocks e. g. caused by hailstorm during the summer cannot damage the sealing of an inverted roof.

The roof sealing of a conventional warm roof is con-stantly exposed to mechanical strains. Many damages already occur during construction on top of the roof, caused by the storage of materials, objects falling down and so forth. In the case of inverted flat roof construc-tions, the viscoplastic thermal insulation layer protects the roof sealing from mechanical strains while at the same time functioning as a protective layer as required according to German DIN 18195-10 norm.

Fig. 6: Sampling from a ten-year-old inverted green roof.

Advantages of Styrodur® C in Inverted Flat Roofs

3.1 Advantages of Styrodur® C in Inverted Flat Roofs

Styrodur® C is commonly used for the construction of inverted flat roofs since the 1970ies and has been approved by Building Authorities since 1978. Sam-ples from functioning inverted roof constructions have shown that the mechanical and physical properties of Styrodur® C given below remain virtually stable through-out extended periods of time (Fig. 6).

Fig. 5: The thermal insulation protects the underlying roof sealing from thermal fluctuation, thermal shock and mechanical damages.

°C

Mechanical damages

UV-rays

Warm roof without gravel Warm roof with gravel

Mechanical damages

UV-rays

°C

Inverted flat roof

Mechanical damages

UV-rays

°C

°C

Fig. 7: Thermal stress of a warm roof and inverted flat roof.

Winter

Summer

0 12 0 12 0 12 0

80 60 40 20 0 -20

Time of Day

°C

Winter

Summer

0 12 0 12 0 12 0Time of Day

°C 80 60 40 20 0 -20

Winter

Summer

0 12 0 12 0 12 0Time of Day

°C 80 60 40 20 0 -20

Warm roof without gravel Warm roof with gravel Inverted flat roof

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Water resistance: Due to its closed-cell foam structure and the double-sided foam membrane, the insulation boards hardly take in any water. The moisture content of Styrodur® C boards that have been lying underneath graveled roof constructions for many years was approx. 0.1 % which hardly affects the thermal insulation boards in any way.

Hohe Festigkeit: Styrodur® C eignet sich durch seine Festigkeitseigenschaften ideal als Dämmstoff für UK-Dächer. Für besonders stark be lastete Dämmstoffe, beispielsweise beim Parkdach, empfehlen sich die außerordentlich druckfesten Typen Styrodur® 4000 CS und 5000 CS.

Brandschutzklassifizierung: Styrodur® C ist im Brand-verhalten in die Euroklasse E nach DIN EN 13501-1 (Brandverhalten von Baustoffen) eingestuft. Die bauauf-sichtliche Zulassung lautet Z-23.15-1481.

Dimensional stability: The extrusion process as well as the controlled storage of the material before dispatch, guarantee a very high dimensional stability. The material is resistant to deformation at loads and temperatures as defined in DIN EN 13164.

Cold bridges: No cold bridges will form when installing Styrodur® C boards with all-around rabbet edges.

Handling: In order to process the Styrodur® C boards you will only need the tools usually applied for wood-work. Connections and cutouts can be easily handled with clean-cut edges that will not crumble.

Constructing an inverted flat roof basically results from the requirement to protect the roof sealing from all static, dynamic and thermal influences.

Those requirements became law with the German DIN 18195-10 norm, which also indicates that protective layers can just as well be of practical use for the building, e. g. the thermal insulation layer also acts as a protective layer for the roof sealing.

Styrodur® C,

Can take on static functions and transmit all occur-ring loads due to its high compressive modulus of elasticity.

Can uncouple the superstructure and the substruc- ture including the supporting structure and the roof sealing due to its viscoplastic yet solid structure.

Helps save heating and cooling energy and protects the building from intensive climatic conditions.

All those properties of Styrodur® C make it easy for the planner to decide in favor of an inverted flat roof when building heavily strained flat roof constructions.

Fig. 8: Due to the closed-cell foam structure of Styrodur® C it is extremely resistant to water.

Advantages of Styrodur® C in Inverted Flat Roofs

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4.1 Substructure

The inverted flat roof as a thermal insulation system is applicable for unventilated flat roofs with heavy as well as light substructures as long as the following require-ments are met:

Heavy substructures like massive ceilings must have a mass per unit area of 250 kg/m2. Light substruc-tures with a mass per unit area of less than 250 kg/m2 must show a surface coefficient of ≥ 0.15 m·K/W.

The high mass per unit area and the required surface coefficient of the substructure shall protect the ceil-ing‘s underside from the formation of condensate in the case of cold rain.

Areas on which roof sealing is to be installed have to be clean and free of foreign substances. Concrete pave-ments or sloping concrete must be sufficiently solid and dry on the surface. The dimensional tolerance according to German DIN 18202 and the “Guidelines for Flat Roof Constructions” must be met.

Inverted flat roofs with Styrodur® C do not need an incline. Although small amounts of water will retain on the flat roof after a rainfall, this does not affect the func-tionality of the inverted flat roof as long as they do not permanently flood the insulation boards.

4.2 Roof Sealing

For inverted roof constructions with an incline of more than two percent all conventional sealing materials are suitable:

Bitumen roof sheeting Polymer modified bitumen sheets Plastic sheeting High polymer plastic sheeting

Inverted flat roofs with an incline of less than two per-cent are special constructions and need specific provi-sions to avoid risks from standing water. That is why in the case of bituminous sealing there needs to be either two layers of polymer modified bitumen sheets or two layers of bitumen roof sheeting. If the roof sealing is made from plastic sheeting the membranes need to be accordingly thick. In any case we suggest a look into the processing specifications of the manufacturer or the Guidelines for Flat Roof Constructions.

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Attention: Tar-bitumen roof sheeting or any solvent-based seal-ing is not suited for the construction of inverted flat roofs using Styrodur® C.

4.3 Roof Drainage

Because the membrane is installed underneath the insulation layer, the drainage has to take place above and below the insulation boards. That is why you need a roof intake with two drainage levels (Fig. 9). The requirements for a professional installation of those intakes should be researched in advance in order to avoid that the Styrodur® C boards are constantly under water due to the intakes having been installed at too high a level.

For inverted flat roof construction you need either of the roof intakes per m2 specified in Index 4, depending on the utilization.

Index 4: Diameter of roof intake depending on the utilization and the expanse of the flat roof.

Diameter of Expansion (m²) of: roof intake

Ø in mm Flat roof < 15 ° Kiesdach Green roof

70 70 112 187

100 187 300 499

125 337 540 899

Substructure n Roof Sealing n Roof Drainage

Gravel seeping layerGeotextile

Styrodur® C

Roof sealing

Reinforced concrete pavementRoof outlet

Fig. 9: Roof intake with two drainage levels for the drainage of the surfaces on top of and below the insulation layer.

4. Applications

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4.4 Thermal Insulation Layer

In order to avoid cold bridges, inverted flat roof con-structions require Styrodur® C boards with all-around rabbet edges. The boards are conjoined in one layer slotted tight with transverse joints (avoid butt joints). In the case of parapet walls or above-grade masonry with bituminous insulation, the Styrodur® C boards are to be aligned with the insulation block which will allow for an installation of the boards that is completely free of cold bridges. Because the insulation boards lie only loosely on top of the roof sealing they do not affect each other in the case of thermal expansions.

It has proven necessary to install the insulation layer as a single layer. If installed in two layers, a film of water can emerge between the insulation boards that can work as a vapor barrier. Thus the water vapor diffusion would be stopped which could lead to concentration of moisture inside the insulation material.

In special cases the Styrodur® C boards can be glued pointwise with the sealing e. g. in bituminous sealing with blown bitumen B25/85 or cold bitumen adhesive.

The thermal insulation layer with Styrodur® C boards is accessible for persons and vehicles alike. For transports on the insulated surface use carts with pneumatic tires. Solvents or solvent-based materials will damage the Styrodur® C boards.

Styrodur® C boards can be stored outside for several weeks with no extra protection against the elements because neither rain, snow nor frost can damage Styrodur® C. If the Styrodur® C boards are stored over

extended periods of time, they should be covered with light-colored plastic foil to protect them against the sunlight. Do not use dark or transparent cover because those can lead to high temperatures underneath.

4.5 Protective Layer

As mentioned above, the thermal insulation layer within an inverted flat roof construction lies always on top of the roof sealing. Therefore the insulation material is exposed to the elements throughout the year. The polymer chains of the closed-cell rigid foam can not permanently sustain ultraviolet rays which is why it is necessary to always install a protective layer on top of the insulation. Said protective layer fulfills the following functions:

Protecting the insulation boards from direct UV-rays Protecting the interconnected roof layers from the

effects of wind suction Protecting the roof from flying sparks and radiating

heat (solid roof covering) Protecting the insulation boards from floating

Generally the protective layer is composed of gravel. However, it can just as well be the top layer depending on the use of the roof e. g. as a green roof, roof terrace or parking deck. Therefore the material of the protective layer depends on the use of the roof.

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Fig. 10: Roof intake.

Note:If Styrodur® C is installed below roof membranes, sheeting or protective coating, the boards could tend to deform during the summer when exposed to high temperatures. Therefore it is vital to install the protective layer immediately according to the “Guidelines of Flat Roof Constructions”.

Fig. 11: Inverted roof with gravel.

Thermal Insulation Layer n Protective Layer

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5. Applications

5.1 Inverted Gravel Roof

In this case a layer of gravel (washed, round gravel Ø 16/32) functions as the protective layer of the inverted flat roof. The layer of gravel corresponds with the thick-ness of the insulation layer. If necessary the gravel can be covered with a sealer, however the sealer must not form a film on the Styrodur® C boards. If the insulation boards are thicker than 50 mm, and a supplementary polymer fleece is installed it might be enough to reduce the gravel layer to 50 mm, even with insulation boards that are much thicker (Index 5).

A polymer fleece that is resistant to decay and capa-ble of capillary diffusion that is installed between the insulation layer and the gravel can protect the sealing from damages caused by penetrating small parts of the gravel. At the same time, the weight of the gravel pre-vents the Styrodur® C boards from any shifting or tilting that might be caused by water or wind. By no means install a polymer membrane or polythene sheet because they function as a vapor barrier, which would cause the insulation layer to take in the water accumulating under-neath.

After each rainfall, small amounts of water remain on the roof sealing which must have the chance to evaporate. It usually does so through the grooves of the boards by diffusing through the insulation material. That is why there always has to be a layer capable of diffusion on the of the insulation layer.

Protection measures against the effects of wind suction have to be taken according to DIN 1055-4:2005-03 or DIBt Approval No. Z-23.4-222 (see Index 6). Geographically exposed constructions might need a much higher load than indicated in Index 6. Examples would be constructions built on ridges or hillsides that are exposed to strong winds or constructions in inner cities, surrounded by even higher buildings that can cause extreme strong winds or turbulences.

Roofs that are accessed regularly (e. g. for chimney or ventilation inspections) should be equipped with walk-on pavement slabs.

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Index 6: Protecting the roof from the effects of wind suction.

Heigt of Fringe according to DIN 1055-4 b/8 Remaining surfaceat eave above least 1,00 m (b = width of fl at roof) railing

0 – 8 m ≥ 1.0 kN/m2 ≥ 60 mm ≥ 0.5 kN/m2 ≥ 50 mm gravel layer gravel layer

> 8 – 20 m ≥ 1.6 kN/m2 ≥ 90 mm ≥ 0.6 kN/m2 ≥ 50 mm gravel layer or slabs (350 x 350 x 60 mm) gravel layer

on fi ne gravel or support

> 20 – 100 m ≥ 2.0 kN/m2 ≥ 120 mm ≥ 0.8 kN/m2 ≥ 50 mm gravel layer or slabs (500 x 500 x 80 mm) gravel layer

on fi ne gravel or support

Inverted Gravel Roof

Fig. 14: Structure of inverted roof with gravel.

in mm without fl eece with fl eece

30 – 50 50 50

60 60 50

80 80 50

100 100 50

120 120 50

Thickness of insulation layer

Layer of gravel (in mm)

Index 5: Protecting the Styrodur® C boards against fl oating.

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5.2 Duo Roofs

The duo roof is one option of inverted flat roofs, that should be taken into consideration if the requirements concerning the thermal transmission coefficient are especially high and the required thickness cannot be met with one layer of insulation. In this version one layer of Styrodur® C thermal insulation is installed below and on top of the roof sealing.

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Fig. 14: Installation of Styrodur® C boards on duo roof.

Fig. 16: Installation of Styrodur® C on top of roof sealing.Fig. 15: Parapet insulation with Styrodur® C.

Duo Roofs

Fig. 13: Structure of duo roof.

A barrier on top of the reinforced concrete pavement is not necessary. Depending on the climatic conditions in some cases there is not even the need for a vapor barrier.

Compared to standard inverted roofs, the duo roof has the advantage of requiring a thinner insulation layer because according to DIN 4108-2 there is no cold bridge addition.

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5.3 Plus Roofs

The plus roof construction is the perfect choice to reconstruct an old, insufficiently insulated warm roof so as to meet today’s thermal insulation requirements. In order to reconstruct an existing warm roof with gravel into a plus roof with Styrodur® C, the following steps are necessary:

The existing layer of gravel is removed in sections and stored upon the roof, considering the given static requirements.

Next, the existing sealing is examined for permeable spots and repaired if necessary.

The same is done for above-grade masonry, skylights, ventilation plugs and roof gutters.

Circuit points need to be 15 cm above the top edge of the gravel for rising parts and at least 10 cm for roof gutters.

Now the Styrodur® C boards are installed and cove red with a geotextile and the gravel is put back on top. Follow the described technique in sections until the complete roof is reconstructed.

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sFig. 19: Gravel roof.

Fig. 18: Reconstructed inverted roof in form of a plus roof construction.

Fig. 17: Left – new plus roof; Right – old warm roof construction.

If the reinforced concrete pavement provides the necessary load-bearing capacity, a reconstructed warm roof can just as well be made into a green roof but it is vital to check whether the roof sealing is strong enough to withhold the formation of roots; if necessary apply a second layer.

Plus Roofs

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5.4 Green Roofs

As long as there is a professionally reconstructed inverted roof i. e. with a layer open for diffusion above the thermal insulation – it is possible to build a green roof with water areas, pathways and little plazas.

The inverted green roof construction holds many advan-tages compared to a warm roof. The thermal insulation protects the roof sealing – with root barrier – against thermal strains at any time. Especially during construc-tion, the insulation package prevents the sealing as well as the root barrier course from damages caused by mechanical strains. Moreover, once the green roof is in use, the thick thermal insulation lies like a protective hand on top of the roof sealing whenever rakes or other garden appliances come into use.

During the construction period of a green roof there is a clear separation between the trades. The roofer is in

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– 10 °C 0 °C + 10 °C + 20 °C + 40 °C

– 10 °C Outside temperature + 35 °C

+ 20 °C Indoor temperature

Temperature profi le

+ 30 °C

Fig. 22: Strain of a green roof.

Fig. 20: Green Roof.

Green Roofs

charge of the sealing and thermal insulation while the roof gardener takes care of the substratum and the greening.

Obviously, the extruded foam insulation boards of an inverted roof construction must not be permanently covered by rainwater. Therefore it needs the following considerations when planning the water storage for an inverted green roof: To comply with the requirements of construction physics and the principles of inverted flat roofs, a layer open to diffusion must be placed between the water storage level and the thermal insulation boards i. e. made from Styropor® C compact boards (Fig. 23).

Fig. 21: Vital cityscape created with green roofs on Styrodur® C.

SubstratumFleece filterSeeping layerGeotextileStyrodur® CRoot barrier course Roof sealingReinforced concrete pavement

17

Due to the “egg carton” shape of these boards (e. g. Zinco WD 65) the rainwater will retain on the surface while the excess water is drained through the cavities onto the rear side.

Another alternative is the vegetated accessible roof terrace (Fig. 24). Part of this construction is a fleece, which is positioned between thermal insulation layer and drainage course. This layer drains the excess rainwater while the cavities inside the gravel course function as a sealing capable of diffusion for the extruded foam boards. On top of the gravel drainage course the construction types may vary. Part of the roof could be covered with a ponding system made from welded membranes. Other parts could be made into a terrace with bedding sand and fleece or fleece and a substratum for greening the roof.

The planner always has to take into consideration that the roof must be able to bear the load of the substratum in wet conditions as well as the possible weight gain of the plants (Index 7). The thermal insulation boards used for inverted rooms must bear a long-term compressive stress of 130, 180, or 250 kPa depending on the materials used which corresponds with load effects of between 13, 18 and 25 tons per square meter.

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Fig. 24: Vegetated accessible roof terrace with irrigation system from ponds on an inverted roof construction with a full gravel drainage course.

Fig. 23: Styropor® compact boards for the drainage and reten-tion of water on a green inverted flat roof with Styrodur® C.

Index 7: Surface load caused by vegetation in wet and leafy conditions.

Type of vegetation

Surface load kg/m2 kN/m2

Lawn 5.0 0.05

Small bushes and groves 10.0 0.10

Bushes up to 1.50 m 20.0 0.20

Bushes up to 3 m 30.0 0.30

Tall bushes up to 6 m 40.0 0.40

Small trees up to 10 m 60.0 0.60

Trees up to 15 m 150.0 1.50

Green Roof

18

Extensive Green Roofs

Extensive green roofs only need little or no maintenance except maybe one or two inspections a year.

Natural processes mostly cover irrigation and fertiliza-tion.

The plants only need additional irrigation during the growing periods. For the most part, extensive greening consists of draught tolerant plants that are compatible with extreme conditions and regenerate quickly e. g. expansive small plants (15 cm height). The substratum should be approx. between 6 and 16 cm.

The substratum of an extensive green roof is drained by the drainage course underneath it. A fleece filter should be positioned in between the two layers. Several green roof contractors offer a substratum that functions as fertilization for the plants and also drains the roof of any excess rainwater. In many cases those substratum layers consist of expanded clay or shale. Generally the planner has to take into account the condition of the various plants as well as their appearance.

Intensive Greening

Intensive greening can be divided into simple and high maintenance greening. Simple intensive greening requires a medium amount of maintenance due to rather uncomplicated requirements of the plants concerning the construction of the layers as well as irrigation and fertilization (Grass, bushes or groves up to 1.5 m).

High maintenance intensive greening, however, is to be planned thoroughly and needs the constant care of a gardener. It needs irrigation, fertilization, mowing and weeding. Generally the substratum is between 10 and 60 cm, depending on the use of the roof. The height of the plants should be between one and three meters. The possibilities of utilization and design of such roofs are practically boundless.

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Vegetation (sedum, moss, herbage)

Substratum (low in nutrients, draining)

Geotextile approx. 14 g/m2

Styrodur® C

Root barrier course

Roof sealing

Reinforced concrete pavement

Fig. 25: Profile of an extensive green roof.

Fig. 26: Installation of Styrodur® C boards under extensive roof greening.

Fig. 27: Extensive greening with drought resistant plants.

Green Roofs

19

Most suitable are plants from the extensive and low-maintenance intensive greening, ornamental lawns, high-maintenance bushes between three and six meters of height as well as small and tall trees. In order to permanently maintain a green roof – whether exten-sive or intensive – certain points have to be taken into account for every layer.

Root Barrier Course and Roof Sealing

On green roofs the roots of the plants advance as far as the sealing, following the water. To protect the sealing from damages caused by penetrating roots, one should only use sealing membranes resistant to roots. The Pro-

fessional Association for Constructional Greening (FBB) provides a list of all membranes and sheets that are tested to have such properties. An updated version of the list can be found on www.fbb.de.

In the construction of inverted green roofs, the extruded polystyrene rigid foam boards must never be installed above the root barrier course. They would function as a wrong-sided vapor barrier and cause the accumulation of water within the insulation material.

Filter- and Seeping Layer = Drainage

The vegetation on a green roof should be capable of storing great amounts of water in order to survive pos-sible periods of draught. However, excessive water must be disposed of through the seeping layer into the draining pipe or roof outlet. Therefore the seeping layer becomes part of the drainage layer. Small parts of the substratum could damage the seeping layer, so to pro-tect it a fleece filter has to be installed in between the two. The most common choice is synthetic fleece from polypropylene or polyester fiber with a mass per unit area of approx. 140 g/m2. Fiberglass fleece is not suit-able because the alkalinity of the ground and water will damage it.

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Fig. 28: Intensive green roof.

Vegetation (grass, bushes, trees)

Substratum

Fleece Filter

Seepage layer (washed gravel 8/16, Entangled Polymeric Filament Mats, EPS drainage elements)

Geotextile approx. 140 g/m2

Styrodur® C

Root barrier course

Roof sealing

Reinforced concrete pavement

Fig. 29: Profile of intensive green roof.

Green Roofs

20

The Task of the Seeping Layer in Inverted Flat Roofs

The drainage layer absorbs excess water, which cannot be retained by the vegetation and leads it along the roof pitch into a drainage pipe or roof outlet (Fig. 30).

However, the seeping layer of an inverted flat roof must not only drain the excess rainwater but also guarantee the diffusion capability above the thermal insulation material. The water vapor diffuses through the thermal insulation layer and has to get into the seeping layer in order to precipitate there. In certain climatic conditions this condensate can benefit the substratum and the plants of a green roof. If the substratum cannot retain any more water, the condensate flows towards the roof outlet or settles again on the roof sealing only to once again enter the diffusion cycle. The drainage layer has to bear the strain caused by the weight of the substra-tum, various other constructions and the utilization e. g. in case of an accessible green roof. Yet it should be as light as possible in order to protect the substructure from unnecessary strain. Moreover, it has to be resistant to frost and decay. The following materials are suitable as a seeping layer:

Seeping layer from concrete drainage stones Drainage stones are only suitable for rather thick sub-stratum layers. They are generally not that suitable for roof greening because they could cause constructional damages. The constant fall of water washes the lime out of the concrete stone, which could settle as lime hydrate inside the roof outlets and pipes and cause sintering and even clogging.

Seeping Layer from Granular Materials (e. g. Gravel, Expanded Clay or Lava) Especially in the case of extensive greening with a very thin substratum, gravel seeping layers are many times the only choice to reach the mandatory superimposed load of 100 kg/m2. However, for intensive greening with very thick substratum layers seeping layers made from expanded clay or lava are more suitable due to their comparably light weight.

Seeping layers from foam plastics e. g. EPS draining boards or entangled polymeric filament mats (e. g. from polypropylene) are especially light.

In a technical sense, those seeping layers can be con-sidered drainage layers as well. The entangled poly-meric filament mat has a tight fleece on both surfaces, which makes it a drainage system in form of a mat. EPS drainage boards usually need no fleece layer because their foam structure is already tight. Therefore they already meet the requirements for both seeping and filter layers.

When using plastic drainage elements please consider that the constant strain from vegetation as well as utilization can cause reduction or compression of the material. Therefore when using deformable draining elements in order to prove the possible water drainage, one has to assume the thickness of the material after it has been in use for 50 years. Example: Under a strain of 10 kN/m2, one should only calculate 60 – 80 % of the original height of installation (Fig. 31). Manufacturers usually provide the corresponding figures for pre-fabricated drainage elements.

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Substratum

Fleece filter

Seeping layer

Geotextile approx. 140 g/m2

Styrodur® C

Root barrier course

Roof sealing

Reinforcedconcrete pavement

Fig. 30: Layers of an inverted green roof with drainage layer for plane water absorption and the alternative of drainage pipe.

100

80

60

40

20

0

Green Roofs

Fig. 31: Creep behavior of various drainage elements in the course of 50 years. Thickness against strain.

Concrete filter stones Grated matsSlotted PS drainage boards

EPS drainage boards Entangled Polymeric Filament Mats

0 10 20 30 40 50 Strain (kN/m2)

Thickness (%)

21

Fig. 34: Roof outlet with inspection shaft on an inverted green roof with an expanded clay seeping layer.

Roof Drainage and Roof Outlets

The drainage layer has to cover the whole surface of the roof up to any adjacent buildings or above grade masonry. If there are roof outlets with a diameter of 100 mm or more, parts of the area (up to 150 m2) can be defined as a drainage unit. The roof must have a slope of at least 3 %.

If the roof outlets are too far apart there is a risk of excess water accumulating in the drainage layer. For such cases drainage pipes should be installed. In order to guarantee a proper installation, all roof outlets should be at least one meter away from above grade masonry. On an inverted roof all roof outlets must have at least two drainage levels. Both the water from above the roof sealing and the excess water from the drainage layer must be able to flow into the outlet. The same goes for rainwater falling on frozen soil.

The number of necessary roof outlets is determined in the DIN EN 12056-3 norm and DIN 1986. Irrespective of the roof’s size at least two outlets must be installed. Drainage layers made of gravel lead directly towards the two roof outlets (Figs. 32 and 33). On the substratum, a separation barrier made of gravel, which is laid around the outlet, keeps the plants from overgrowing and mak-ing it impossible to inspect the shaft.

In cases of intensive greening with higher substratum layer it is necessary to install an outlet with an inspec-tion shaft.

Such inspection shafts made from concrete or plastic components are easily connected to drainage pipes making them readily accessible for inspection or clean-ing (Fig. 34).

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Fig. 32: Roof outlet of an inverted green roof with a gravel seeping layer.

SubstratumFleece filterGravel seeping layerGeotextile approx. 140 g/m2

Styrodur® C

Root barrier courseRoof sealingReinforced

concretepavementRoof outlet

SubstratumFleece FilterGravelEPS seeping layer Styrodur® CRootbarrier course

Roof sealingReinforced concretepavement

Roof outlet

Fig 33: Roof outlet on an inverted green roof with EPS drainage boards.

SubstratumInspection shaftFleece FilterExpanded clay seeping layerStyrodur® CRoot barrier courseRoof sealingReinforced concretepavement

Roof outlet

Green Roofs

22

Fig. 35: Inverted green roof adjoining above grade masonry with fascia gutter.

Protection against Wind Suction and Erosion

The vegetation of extensive and intensive roof green-ing functions as the gravel layer required for all inverted roofs i. e. it protects all underlying layers from the effects of wind suction. Many times the vegetation alone won’t be enough to protect the edges and corners from these forces so an additional layer of gravel or concrete slabs or a combination of a superimposed load and a mechanical fixation will be necessary.

For determining the wind load one must consider the German DIN 1055-4 or DIN V ENV 1991-2-4 norms, as well as the required superimposed load for the protec-tion against the effects of wind suction according to DIBt approval no. Z-23.4-222. A protective barrier made of gravel along the parapet will additionally provide fire protection and protect the edge of the roof from over-growing plants. Index 8 indicates the thickness and superimposed loads required for various forms of veg-etation. The figures may vary depending on the object. During the installation and growing phase, the effects of wind and rain can cause erosion of the various layers of the green roof, which can be avoided by means of a stable vegetation layer and higher load assumption.

Additionally, broken stone can improve the stability of a fine-textured vegetation. The easiest way to minimize the dangers of erosion is to choose plants and vegeta-tion suitable for green roofing e. g. quick to expand across the surface of the roof. In those areas that are especially “severely exposed” to the wind, hydro-seed-ing and pre-cultivated vegetation mats can lower the risks of erosion.

If a green roof is bordering on above grade fascias, gutters should be installed at the base of the building. Those gutters provide a straight and quick flow of the rainwater accumulating at the fascias without addition-ally soaking the green roof construction. Also, fascia gutters in front of windows and garden doors can addi-tionally dispose of excess water before it can penetrate through the grooves (Fig. 35).

Vegetation

Selecting and combining the plants for the vegetation of a green roof is a very difficult and complex task, which should be left to a specialist e. g. a landscape or garden architect or a gardener specialized on green roofs.

The intended purpose as well as the type and form of vegetation have to be planned ahead just as thoroughly as the aforementioned constructional requirements. In addition one has to preconceive how to secure the long-term functionality of the green roof as well as the expected expenses for building and maintaining it.

As soon as constructor and planner have settled these basic conditions they have to choose the right physical, chemical and biological properties and care for the right material and dimension of the vegetation necessary for the plants to grow. The substratum has to be root per-meable and solid while being able to storage enough seeping water and incorporate enough air for the veg-etation.

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Foundation slabs

Substratum

Fleece Filter

Seeping layer

Geotextile approx. 140 g/m2

Styrodur® C

Roof sealing

Reinforced concrete pavement

Masonry

Elastic sealing

Fixing profile

Fascia gutter

Gravel 16/32

Gravel 8/16

Green Roofs

23

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*for a 2 – 3 % slope; for more than 3 %, the depth can be reduced to 3 cm.

Fire Protection

The ARGEBAU (The Conference of the Ministers and Senators of the Federal States Responsible for Building, Housing and Settlement) has come up with fire protection requirements as an amendment to already existing building regulations. According to these requirements, intensive greening constitutes “hard roofing”.

Extensive greening is considered as sufficiently resistant if the mineral vegetation layer is at least 3 cm, if the type of vegetation constitutes only little fire load and if the plants are at least 50 cm apart from all roof penetrations and above grade masonry. There needs to be protective space consisting of either reinforced concrete slabs or 16/32 mm coarse gravel (Fig. 36).

Fig. 36: Gravel shoulder along the edges and permeations of the roof.

Index 8: Required depth of layers and distributed loads for various types of vegetation.

Types of vegetation Depth of Total depth of Load assumption vegetation layer greening construction in cm in cm With 2 cm With 4 cm kg/m2 kN/m2 drainage mat ballast layer*

Extensive greening, low maintenance, no additional irrigation

Moss/sedum greening 2 – 5 4 – 7 6 – 9 10 0.10

Sedum/moss/haulm greening 5 – 8 7 – 10 9 – 12 10 0.10

Sedum/grass/haulm greening 8 – 12 10 – 14 12 – 16 10 0.10

Grass/haulm greening (dry grass) ≥ 15 ≥ 17 ≥ 19 10 0.10

Simple extensive greening, medium maintenance, periodic irrigation

Grass/haulm greening (grass roof, poor grassland) ≥ 8 ≥ 10 ≥ 12 15 0.15

Wild shrub/grove greening ≥ 8 ≥ 10 ≥ 12 10 0.10

Grove/shrub greening ≥ 10 ≥ 12 ≥ 14 15 0.15

Grove greening ≥ 15 ≥ 17 ≥ 19 20 0.20

Complex intensive greening, Depth of Total depth high maintenance, drainage layer of construction regular irrigation in cm in cm

Lawn ≥ 8 ≥ 2 ≥ 10 5 0.05

Small shrubs/grove greening ≥ 8 ≥ 2 ≥ 10 10 0.10

Medium shrubs/grove greening ≥ 15 ≥ 10 ≥ 25 20 0.20

Tall shrubs/grove greening ≥ 25 ≥ 10 ≥ 35 30 0.30

Shrub greening ≥ 35 ≥ 15 ≥ 50 40 0.40

Tree greening ≥ 65 ≥ 35 ≥ 100 ≥ 60 ≥ 0.60

Green Roofs

24

5.5 Roof Terrace

The roof sealing and thermal insulation of a roof terrace are installed in the same way as on an inverted gravel or green roof. The top layer is either a solid, walk-on pave-ment made from washed-out concrete, pre-constructed ceramic slabs, paving stones or grid construction, laid either on crushed stones or paving slab supports. That way there is an extra layer – capable of diffusion – between the thermal insulation and the pavement,

which guarantees the diffusion of the water vapor through the insulation material.

If the cover is to be laid on top of crushed stones, the Styrodur® C insulation boards are to be protected by a protective fleece so that no particles or chippings can get between the groves or underneath the slabs.

The geotextile is made either from polypropylene or polyester fiber. Best suitable for inverted flat roofs are stable fleece filters capable of diffusion with a mass per unit area of approx. 140 g/m2.

Polythene sheets are not capable of capillary diffusion therefore they are not suitable. On top of the geotextile is an approx. 3 cm thick layer of frost resistant grit or fine gravel (3 – 8 mm) on top of which the pavement is laid (Figs. 38 and 39).

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Fig. 37: Fire compartment of an inverted roof with extensive greening.

Fig. 38: Roof terrace.

In all buildings including town houses, the building’s partition walls, firewalls or those who are approved to substitute firewalls have to be no more than 40 m apart from each other and at least 30 cm above the substra-tum (Fig. 37).

Roof Terrace

Concrete Slabs

Crushed stones

Geotextileapprox. 140 g/m2

Styrodur® C

Roof sealing

Reinforced concrete pavement

Fig. 39: Profile of inverted roof terrace with concrete slabs bedded in crushed stones.

Substratum

Fleece Filter

Styrodur® C

Root barrier course

Roof sealing

Reinforced concretepavement

Parapet plate

Insulation wedge

Flame retardantinsulation layer

Masonry

Skylight

Masonry

Window

Gravel

Substratum

25

5.6 Parking Decks

The roofs of public buildings, warehouses and big department stores are increasingly used as parking decks. To minimize the heat loss from the heated areas below the parking deck, they are insulated with Styrodur® C boards following the principles of inverted roof constructions. Due to their high compressive strength Styrodur® C boards can handle the strain of parking and moving cars if the following constructional guidelines are followed. The construction of the driving surface can be handled in different ways following the principles of inverted flat roofs.

Fig. 42 shows the structure of a conventional parking deck with thermal insulation. In these constructions the roofing near the grooves of the concrete slabs can be very easily damaged due to the dynamic load of the moving wheels. In an inverted roof construction, the roof sealing is protected from such dynamic loads by the thermal insulation layer.

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An alternative construction is the use of a plastic pav-ing slab support that is weatherproof and resistant to decay. The paving slab support is located at the inter-sections of the slab’s grooves. Spacers guarantee a regular pattern of the grooves. Excess water will be lead underneath the slabs unto the thermal insulation.

The surface water draining through the open grooves causes a certain self-purification process between the thermal insulation boards and the pavement. Never-theless, at least once a year one should lift a few of the slabs and rid the spaces between them from any accu-mulated dirt.

Option 1: Large-Sized Concrete Slabs on Pavement Slab Support

Reinforced pre-fabricated concrete slabs (1500 x 2000 x 80 mm) are laid on top of the Styrodur® C boards, which are covered by a polyester fleece (open to capil-lary diffusion). However, around their edges, the boards are approx. 100 mm thick, leading to a 20 mm high void between the concrete slabs and the thermal insula-tion boards which enables the atmospheric moisture to diffuse (Fig. 43). In order to keep the concrete slabs from shifting under the traffic load the edges should be equipped with rubber cushions that transmit the hori-zontal forces between the slabs.

The sealing of a warm roof is especially strained at the grooves of the driving surface.

The insulation layer on top protects the sealing of an inverted roof.

Fig. 42: Parking deck in the form of a conventional warm roof construction and inverted flat roof. The roof sealing of the warm roof construction could be damaged, whereas it lies safely protected in the inverted roof construction.

Fig. 41: Parking deck.

Reinforced concrete slabsAir fi lmGeotextileapprox. 140 g/m2

Styrodur® CRoof sealingReinforcedconcrete pavement

Fig. 43: Parking deck with large-sized reinforced concrete slabs on paving slab support.

Parking Decks

Fig. 40: Inverted roof terrace with Styrodur® C. Laying of the concrete slabs into the bedding.

26

Because, the weight of the cars is only transmitted onto the thermal insulation boards via the edges of the concrete slabs (point load) it is necessary to install Styrodur® 5000 CS insulation boards with high com-pressive strength. Since leveling is not possible when installing these large-size boards it is very important that the reinforced concrete pavement including the sealing does not show any swelling and the thermal insulation boards can be laid onto the full surface.

Option 2: Small-Size Concrete Slabs on Paving Slab Support

The surface of a parking deck can just as well be constructed of small-sized concrete slabs (600 x 600 x 80 mm) laying on paving slab support system in order to guarantee the voids between the top surface of the insulation boards and the driving surface required by construction physics (Fig. 44 and 45). The slab support can be made e. g. from special plastic rings or rubber plates.

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Thanks to the plastic or rubber slab support adjusted to the covering, the height of the concrete slabs can be altered during construction as well as during operation. Similar to Option 1, tile spacers or rubber plates around the edges protect the concrete slabs from shifting.

The pre-constructed concrete slabs (following strict production guidelines) are weatherproof and resistant to road salt. High quality concrete and system solutions with certificated and tested cone-like spreading elements guarantee a horizontally braced driving sur-face, which is weatherproof and can be installed in the shortest of times (Fig. 46).

Fig. 45: Concrete slabs laid on Styrodur® C using paving slab support.

Concrete Slabs

Air film

Paving slab support

Styrodur® C

Roof sealing

Reinforced concrete pavement

Fig. 44: Parking deck with stilted small-sized concrete slabs.

Fig. 46: Parking deck with concrete slabs; inverted roof construction with Styrodur® C.

Parking Decks

27

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Option 3: Parking Deck with Composite Paving

Except for the polyester fleece, this structure is identical with the aforementioned constructions. For the bedding layer of the composite paving we suggest frost resistant grain selected grit (grain size 2/5 mm). After the com-paction process the bedding layer should be approx. 5 cm deep. The necessary slope of > 2.5 % should be pre-determined by the reinforced concrete pavement.

All further layers are equal in depth running parallel to the reinforced concrete pavement.

Suitable coating would be pre-cast concrete block, clinker or natural stones. The composite paving should preferably be at least 10 cm deep (Fig. 47). The shape of the stones is very important for the stability of the driving surface. The stones should be interlocking at the edges in order to avoid possible opening of the grooves parallel to the centerline and pitch axis of the composite (Fig. 48). The grooves in between the stones should be filled with paving sand (grain size 0/2 mm). Before the final consolidation the covering should be re-sanded.

Here, natural crushed stone fines have proven most suitable.

Only Styrodur® 5000 CS is suited for parking decks with composite paving for only these insulation boards provide the sufficient compressive strength for the expected traffic loads and the necessary rigidity to avoid excessive sagging. High elastic deformations would cause vertical movements of the surface and compromise the stability of the construction as a whole.

Fig. 49: Composite paving with grooves for a parking deck on top of a gymnasium.

Fig. 48: Stone shapes for stable pavement.

Composite paving

Paving sand

Bedding layer

Geotextile approx. 140 g/m2

Styrodur® C

Roof sealing

Reinforced concrete pavement

Fig. 47: Parking deck construction with composite paving on top of bedding layer.

Fig. 50: Concrete pavement on Styrodur® C boards.

Parking Decks

28

Option 4: Parking Deck with Cast-In-Place Concrete

The construction of parking decks with cast-in-place concrete on an inverted roof is a very recommendable solution for highly frequented parking spaces. This spe-cial construction requires thorough planning and execu-tion.

The principal structure of a parking deck with cast-in-place concrete is schematically illustrated in Fig. 51. A barrier course and the cast-in-place concrete pave-ment are installed on top of the load bearing pavement, the roof sealing, thermal insulation with Styrodur® C.

In the traditional inverted roof construction, precipitable water is leaking into the insulation boards, which cannot happen in the construction with the cast-in-place con-crete. The reduced heat insulation of the inverted roof, caused by the precipitable water below the insulation boards causes economical disadvantages contrary to the construction with cast-in-place concrete where any additional charge would not be justifiable and therefore is not imposed. In this type of construction the pre-cipitable water is drained completely over the driving surface. Therefore it is not necessary to place an extra layer that is capable of capillary diffusion on top of the extruded foam. With no water under the thermal

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Cast-in-place concrete

Geotextile approx.140 g/m2

Styrodur® C

Roof sealing

Reinforced concrete pavement

Fig. 51: Basic outline of a parking deck with cast-in-place concrete on top of an inverted roof construction with Styrodur® C.

Parking Decks

insulation boards there is hardly any water vapor diffusion. The roof sealing below the insulation layer considerably reduces the transport of the water vapor diffusion from the inside of the building. That way, no condensate can form within the insulation layer, which is why there is no need for an extra layer open to capil-lary diffusion.

Certainly, the planner and builder of such a construction have to work very thoroughly in order to guarantee that the water is always completely drained off through the surface of the cast-in-place concrete pavement.

Moreover, there are a few basic instructions for the construction of such a roof and it is most important that they are followed in order to guarantee the long-term successful operation of the parking deck with cast-in-place concrete. These instructions are neither generally valid nor complete, which is why it is vital that each indi-vidual case is treated as such by a specialized engineer.

Roof Construction:

The slope of the load bearing reinforced concrete pavement must be at least 2.5 %.

The roof sealing has to be installed in direct con-tact with the reinforced concrete pavement so that in case of leakage no precipitable water can come underneath the sealing. This makes it easier to find the damage below the driving surface.

The slope of the roof sealing and the cast-in-place concrete pavement have to be at least 2.5 % and going parallel to each other.

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Characteristics of Thermal Insulation in Case of Water Penetrating the Parking Roof Construction

If the water draining top layer – made from cast-in-place concrete with joint sealing – becomes permeable letting the water seep under the Styrodur® insulation, worst that could happen is a calculated moisture absorption of the insulation material. In some parts of the material moisture contents between 10 and 15 Vol.-% is possible during the course of 20 years. This does not limit the static function of the construction. Damages of the insulation material due to frost are impossible; the thermal insulation capability of the material could decline, though.

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Fig. 52: Parking deck with cast-in-place concrete paving.

Parking Decks

Roof Drainage

At the lowest point, roof outlets have to installed (considering sagging roof areas).

Two levels of outlets have to be installed so that in the case of damage both the driving surface and the sealing can be drained without the accumulation of backwater.

The outlets have to be checked and cleaned on a regular basis.

The concrete- or cement mixture has to be com-posed of high quality ingredients in order to keep the drainage system from sintering due to lime hydrate flushing out of the cast-in-place concrete pavement.

Cast-In-Place Concrete Pavement

The minimum depth of the cast-in-place concrete layer has to be 12 cm.

The quality and processing of the concrete have to guarantee resistance against frost, decay and abra-sion on a long-term basis.

The concrete’s surface has to be resistant to abra-sion and slip-proof for driving.

If necessary, the concrete slabs are to be doweled according to the specifications for the bearing structure. The measuring of the reinforcement has to follow the theory of elastic bedding.

Formation of Grooves

The spaces between the grooves should be between 2.5 and 5 m.

The planning and construction of long-term elastic sealed grooves (groove backfill) is to be executed by a specialist.

The durability of a parking deck constructed with cast-in-place concrete pavement depends a great deal on the choice of joint sealing – its installation and quality.

30

Note

The information submitted in this publication is based on our current knowledge and experience and is referring only to our product

and its properties at the time of going into print. It does not imply any warranty or any legally binding assurance about the condition

of our product. Attention must be paid to the demand of specific applications, especially the physical and technological aspects of

construction and building regulations. All mechanical drawings are basic outlines and have to be adapted to each application.

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Research and several publications have shown that the thermal transmission capacities of the extruded foam rises about 2.3 % for 1 Vol.-% increase in moisture content.

With a thermal transmission coefficient of 0.032 W/(m2·K) in a dry state, due to moisture absorption caused by the failure of the joint sealing that thermal transmis-sion coefficient would rise up to between 0.039 and 0.043 W/(m2·K). Presumably, the worse coefficient would be restricted to those areas of the parking deck surrounding the drainage system. Therefore, based on the total energy demand of the building the additional heat loss would be rather small.

The thermal transmission coefficient of alternative insulation material providing the compressive strength needed for such constructions is between 0.040 and 0.055 W/(m2·K).

The functionality of these constructions was proven by practical examples, which are now over 20 years old.

Fig. 53: Pavement slab made from cast-in-place concrete sliced in order to scientifically examine the long-term properties.

30

Parking Decks

31

6. Technical data Styrodur® C

6 T

ech

nic

al d

ata

Sty

rod

ur®

C

Property Unit1)

Codeaccording

to DIN EN 13164

2500 C 2800 C 3035 CS 3035 CN 4000 CS 5000 CSStan-dard

Edge profile

Surface skin embossed skin skin skin skin

Length x width mm 1250 x 600 1250 x 600 1265 x 615 2515 x 6154) 1265 x 615 1265 x 615

Density kg/m3 28 30 33 30 35 45DIN EN 1602

Thermal conductivity lD [W/(m.K)]

Thermal resistance RD [m2.K/W]

lD

RD

lD

RD

lD

RD

lD

RD

lD

RD

lD

RD

DIN EN 13164

Thickness 20 mm30 mm

40 mm 50 mm 60 mm 80 mm 100 mm 120 mm 140 mm 160 mm 180 mm

–––––––––––

0.0320.032 0.0340.0340.034

––––––

0.650.951.251.501.80

––––––

0.0320.0320.0340.0340.0340.0360.0380.038

–––

0.650.951.251.501.802.302.803.20

–––

–0.0320.0340.0340.0340.0360.0380.0380.0380.0380.040

–0.951.251.501.802.302.803.203.654.204.45

–0.0320.0340.0340.0340.036

–––––

–0.951.251.501.802.30

–––––

–0.0320.0340.0340.0340.0360.0380.038

–––

–0.951.251.501.802.302.803.20

–––

––

0.0340.0340.0340.0360.038

––––

––

1.251.501.802.302.80

––––

Compressive stress or compressive strength at 10% deformation kPa CS(10\Y) 150 – 2002) 200 – 3003) 300 250 500 700

DIN EN826

Compressive creep over 50 years at < 2% deformation kPa CC(2/1,5/50) 60 – 802) 80 – 1003) 130 – 180 250

DIN EN1606

Certificated compressivestress under load bearing kPaloor slabsDIBT

– – – 130 – 180 250DIBT Z-23.34- 1325

Adhesive strength on concrete kPa TR 200 – > 200 – – – –

DIN EN 1607

Shear strength kPa SS > 300 > 300 > 300 > 300 > 300 > 300DIN EN 12090

Compressive modulus of elasticity kPa CM 10,000 15,000 20,000 15,000 30,000 40,000

DIN EN 826

Dimensional stability70 °C; 90 % r. h. % DS(TH) ≤ 5 % ≤ 5 % ≤ 5 % ≤ 5 % ≤ 5 % ≤ 5 %

DIN EN1604

Deformation behaviour: load 20 kPa; 80 °C % DLT(1)5 ≤ 5 % ≤ 5 % ≤ 5 % ≤ 5 % ≤ 5 % ≤ 5 %

DIN EN1605

Deformation behaviour:load 40 kPa; 70 °C % DLT(2)5 ≤ 5 % ≤ 5 % ≤ 5 % ≤ 5 % ≤ 5 % ≤ 5 %

DIN EN1605

Linear coefficient of thermal expansionLongitudinal mm/(m.K)Transverse

––

0.080.06

0.080.06

0.080.06

0.080.06

0.080.06

0.080.06

DIN 53752

Reaction to fire Class – E E E E E EDIN EN 13501-1

Long term water absorption % v/vby immersion

WL(T)0.7 0.2 0.3 0.2 0.2 0.2 0.2 DIN EN 12087

Long term water absorptionby diffusion2 % v/v WD(V)3 2 – 4 – 2 – 4 2 – 4 2 – 4 2 – 4

DIN EN12088

Water vapour transmission2) MU 150 – 50 200 – 80 150 – 50 150 – 100 150 – 80 150 – 100 DIN EN 12086

Freeze-thaw-resistance % v/v FT2 ≤ 1 ≤ 1 ≤ 1 ≤ 1 ≤ 1 ≤ 1 DIN EN 12091

Maximum service temperature °C – 75 75 75 75 75 75 –

1) N/mm2 = 1 MPa = 1.000 kPa 2) Dependes on thickness 3) Thickness ≤ 30 mm 4) Thickness 30 and 40 mm: 2510 x 610 mm

BASF SE

Styrenic Polymers Europe67056 LudwigshafenGermany

www.styrodur.com

KTF

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803

BE

- E

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LIS

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May

200

8

Information about Styrodur® C

n Product brochure: Europe’s green insulation

n Applications

Basement insulation

Load Bearing and Floor Insulation

Wall Insulation

Roof Insulation

Ceiling Insulation

Reconstruction ans Refurbishment

n Technical Data

Recommended Applications and Technical Data

Technical Data and Assistance data for dimensioning

n Chemical Resistance

n Styrodur® C-Movie: Europe’s green insulation

n Website: www.styrodur.com

Sty

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