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ALTERNATE ROOFING MATERIALS
TO R.C.C
• Stone slab roofing
• Jack arch roofing
• Madras roofing
• Deck roofing
● Alternate building materials are those which can be used economically by replacing the
conventional building materials.● These materials are historically appropriate,cost
effective,easy to install,and functional in wildland fire environments.
● Eventually in stone slab roofing different forms of mortar were used to hold the stones together,
cement being the most commonplace now.
INTRODUCTION
STONE SLAB ROOFING
• Where particular geology made it easy to split stones into large slabs or where such flat stones were produced by nature, they formed a natural building material.
• Traditionally, stone slabs provided excellent insulation and unique looks. Stone slab roofs are also solid and virtually stormproof.
• Nowadays, a stone slab roof might be seen as part of the restoration of a heritage building, or as a decorative feature - although rarely as the main roof.
Stone roofs
• Stone roofs are not much used at the present time, except for covering small vestibules, porches, turrets, towers, and monumental buildings.
• They may be flat or pitched. Large slabs are used for flat roofs, and small ones for pitched roofs.
Methods of Construction: CONTEMPORARY METHOD
• It is a flat roofing system with stone slabs resting over steel or slender rcc section beams.
• The slabs are laid over the terracing for insulation and to provide a slope for rain water drainage.
METHODS OF CONSTRUCTION : TRADITIONAL METHOD
• In this system stone slabs are placed over wooden planks which are supported on wooden beams.
• This keeps the building cool and is mainly suitable for hot and dry climate.
• There is no need of centering and shuttering.
METHODS OF CONSTRUCTION
TYPES OF STONE SLAB ROOFING
Ex at Karnak,Egypt
A structure with stone
walls, supporting flat
roof made of stone
slabs of large
boulders.
Corbelled
roof
Flat roof
Gabled
roof
Advantages and Disadvantages
• Good insulation • Beautiful appearance• They are solid and also storm proof• Water proof roofing• Durability
• Very heavy• Labour incentive• An obsolete cladding material • Not suitable to withstand loading from
furniture, etc of modern residential buildings.
JACK ARCH ROOFING
INTRODUCTION• A jack arch is classically defined as a structural element in masonry
construction that provides support at openings in the masonry.
• Alternate names are FLAT ARCH and STRAIGHT ARCH.
• Unlike regular arches, jack arches are not semicircular in form.
• Instead they are flat in profile and are used under same circumstances as lintels.
MATERIALS
• This type of roof may be built with materials such as brick, steel, concrete, and clay-gypsum mortar.
• The roofing technique in auroville is that of jack arch roof with terra cotta hollow blocks and pre cast concrete beams.
ADVANTAGES
• It can be constructed from relatively small pieces of material that can be handled by individuals .
• Arches are typically sawn from an appropriately sized fired clay lintel.
• There is considerable scope for in corporation of decorative patterns and elements into jack arches.
CONSTRUCTION DETAILS
JACK ARCH AT AUROVILLE
MADRAS TERRACE ROOFING
INTRODUCTION
o This is the traditional roofing found in south India.
o It involves the use of wood,“aachikal”(a locally available material which is a small brick)and lime plaster.
o These are commonly used for small spans.
o Wooden beams are used to cover the span, over this wooden beams are laid at intervals of less than 45 cms from each other.
o The gaps between is filled with bricks on edge with lime plaster. Upon this “ aachikal brick “is laid on edge across in diagonal fashion plastered with lime.
CONSTRUCTION DETAILS• STEPS IN CONSTRUCTION
o Teak wood joist are placed on rolled steel joists.
o Sufficient slope is provided.
o Terrace bricks of size 15x75x25mm to be laid diagonally.
o Brick bat concrete of thickness 75mm to be laid.
o Rammed and allow to set for 3 days.
o Flat tiles are then laid over this concrete.
o Surface of this roof is finished with 3 coats of plaster.
Construction Process
ADVANTAGES
• It is easy for construction and maintenance.
• Flat roofs possess good insulation properties.
• It provides better light,ventilation and architectural
appearance to the building.
• Upper floor can be easily constructed.
• Fire resistant.
DISADVANTAGES
• Madras roofs are not suitable for long span ,with out the
introduction of columns and beams.
• Initial cost is less than a pitched roof
• Not suitable for places of heavy snowfall.
• Construction speed is slower than pitched roof
DECK ROOFING
DECK ROOFING
• A flat open portion top of a roof such as a terrace or a sun deck
TYPES OF DECK ROOFING
• Depending upon materials used there are four types of deck roofing.
1.Steel deck roofing.
2.Wood deck roofing.
3.Concrete deck roofing.
4.Cement deck roofing.
STEEL DECK ROOFING
• Materials used in steel deck roofs are light- gauge , cold-rolled sections , welded or screwed to bar joists.
WOOD DECK ROOFING
• Materials used are sawed lumber, asphalt , ply wood or OSB (oriented strand board).
CONCRETE DECK ROOFING• There are four types of concrete deck roofs
1.Structural concrete deck.2.Structural composite concrete deck.3.Precast concrete deck.4.Lightweight insulating concrete deck.
• Concrete roof decks are commonly topside insulatedusing adhered insulation panels or cast-in-placelightweight insulating panels.
USES
• The primary use of steel roof is to support vertical loads and the weather resisting system , such as insulation , roofing and waterproofing materials.
• Deck roofing can be used in garden landscaping , to extend living areas of houses.
Source● http://www.ruralhousingnetwork.in/technology/56adb59c336c497dc92b53d6
● https://www.google.co.in
Thank you!