Why Buildings Leak UVA

8/11/2019 Why Buildings Leak UVA

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Rex A. Cyphers, P.E.

ssoc ate



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Overview• Flashing

• Weather Resistive Barrier Continuity• Sealant Reliant Designs

• Fenestration Systems

• Material Considerations

• Masonry Compatibility

• Mocku s and ualit Assurance



What are ou tr in to avoid?















Ke Elements of Good FlashinRedundancy

Keep in mind thateveryone has a bad day

Your building should be

mind



Flashin RedundancTypical Section at WallBase

Improved Detail with



Flashin Redundanc

Flexible Flashing

Two –Piece Metal

Flashing with Upturned

Back Leg

Clean & Dry Substrate

Flashing Installation

Hemmed Drip Edge



Flashin Redundanc



Ke Elements of Good Flashin

End Dams

.

Without end dams, that path is lateral.






Drip Edges

,

but they are more attractive than mold and efflorescence.




ap er

requires the use of

drip edges formasonry flashings



Ke Elements of Good FlashinMissing Drip Edges




Free Drainage

from the cavity.

,

and weeps wherever possible.










Construction Durability and Sequencing

have to endure during construction as well as what

materials have to be installed first to properly shingleor attach flashings.




and Sequencing



Key Elements of Good Flashing

Construction Durability

and Se uencin







Construction Durability

and Se uencin





Sill Flashing Details

Sill details often include a

pan flashing system tocapture water from thew n ow sys em an recit to either the exterior or

into the cavity.



• Multiple lines ofdefense in case oneproduct fails.

• Products deteriorateover time.

• Products are notalways installed asrequired by themanufacturer and Deterioration of Wood Framing

Due to No Backup Flashing Pan



Beware of blind seals on

flashing panning system.Whenever possible, use

cli s amb fasteners orother methods of sealinganchors to prevent waterleakage through pan.



Jamb Flashin Details• Often amb flashin s are not considered in barrier wall

applications. This often leads to leakage andcondensation issues. Jamb flashings:

epara e e cav y space rom w n ow sys ems,

curtain wall systems, doors, and potentially precast

concrete or l imestone surrounds;

• Prevent lateral flow of air and water penetrating through

permeable claddings by creating a barrier; and

• Can be designed to serve as cavity air barrier tocompartmentalize claddings between window stacks.



Section 1405.3 Flashing

Flashing shall be

of exterior door and

window assemblies,

terminations of exterior

wall assemblies, exterior

wall intersections withroofs, chimneys,…….



Missin Jamb Flashin



Wh Buildin s Leak

Roof-to-Wall Interface Conditions

The intersection between a roof and a cavity wall is

critically important because often even a minor leak

.



Roof-to-Wall Interface



A single defect leads to water in the building.



Wh Buildin s Leak

Air, Water and Vapor Barrier Mistakes

Most air, water, and vapor barrier mistakes are made

around penetrations and openings.



Weather Barrier Continuit



Weather Barrier Continuit• Transition flashings

–barrier continuous at openings in

exterior wall.

• Recommend requiring enlarged Critical Detail

details at jambs of followinglocations:

– Storefronts,

Potential for

Air and Water – Curtain Walls,

– Windows,

– Doors.

Travel



Weather Barrier Continuit• Product Selection

Considerations

– Overall Effectiveness,

– Compatibility with interfacingmaterials,

Termination Bar

Air Barrier

– Redundancy of design,

– Constructability,

– Life expectancy of building,

Flexible Flashing

– Cost.

Multiple Products may beneeded to keep air/water/vapor

. . e e n

Sealant

arr er con nuous.



Mechanical Pi in Penetrations•Holes often created in airbarrier where i es ductwork, and electricalconduit penetrate exteriorwalls

•Sealants or tapes canoften be used around

•Larger penetrationstypically require transition

as ngs•Method used to sealenetrations de endent

upon air barrier material





Structural Members• Structural elements often

interru t exterior walls (Steel beams, columns,

and angles)

• required to transitionweather barrier materials

prevent air and waterleakage around

• Flashings must becompatible with the



Structural Members

Transition Flashing

Needed

Transition Flashing

Needed



Reasons Wh Buildin s LeakSealant Reliant

ea an s o no asforever. If a design

relies solel on asingle line ofsealant, it will leak

.



Sealant Reliant Desi ns



Sealant Reliant Desi nsTypical Sealant Reliant Designs:

arr er recas oncre e ng e y e



Sealant Reliant Desi ns



Two Sta e SealantsTwo sta e sealants rovide a method of incorporating

redundancy into an otherwise“ sin le line of defense”approach to barrier walls.

Detailing of joint continuity andterminations is crit ical and mustincorporate a method ofweep ng space e weensealants.



Maintaining continuity and providing drainage of

screen sea an s ecomes cu w e a on

of intersecting cladding joints or expansion joints.

Wh B ildi L k



Wh Buildin s Leak

Compatibility and Adhesion Issues

Review all materials which ma come into contact with one

another to verify that they will function as intended over the

life of the building.



Material Considerations

a er a pro ems are an ncreas ng ren w regar

to building envelopes because of the rapidly changingtrends in waterproofing and the constant arrival of new.

Three primary considerations for evaluating materials

used for building envelopes are:• Adhesion

• Compatibility

• Exposure




Adhesion:

• Adhesion must be adequate for all materials used.

• Field adhesion testing should be performed at the-

used on the building.

• Always determine cleaning and priming requirements.• Manufacturers should always be consulted in regard to

adhesion to substrates/products.

M t i l C id ti




Compatibility:

• Some materials are not chemically compatible with

each other which can jeopardize performance.

• ,degradation, or reactivity.

• Some materials flash off VOC’s or solvents.

M t i l C id ti




Compatibility

M t i l C id ti




M t i l C id ti




Exposure:

Many weather barriers and flashings are not meant for

prolonged exposure to the environment.

with regard to sequencing and protecting the work.

• Exposure to sunlight and heat• Dust and dirt accumulation

• Water damage

• Embrittlement

Reasons Wh Buildin s Leak




Window Leakage Problems

n ows an enestrat ons are comp ex assem es o

extrusions, gaskets and seals. Careful coordination ofthe s stem, the substrate, anchors and closures is

necessary to prevent leaks.

S ecif in Windows



S ecif in Windows

• AAMA 101 “North American Fenestration, ,

Skylights” specifies the following performancerequirements:

• Design pressure, Structural test pressure, waterpenetration resistance, life cycle testing and air

leaka e rates.• Requirements are based on the windows

performance class and performance grade.

• Performance classes: R, LC, CW and AW

S ecif in Windows



S ecif in Windows

• 2006 International Energy Conservation Code,

• Prescriptive requirements for a window’s U-factorand SHGC (except in northern climates);

• Mandatory requirements for air leakage rates

• National Fenestration Ratin Council testslabels, and certifies windows for energy relatedperformance requirements such as U-factor,

, ,

resistance• An additional ro ect s ecific LEED or buildin

energy model requirements should be

considered as well

S ecif in Windows



S ecif in Windows

• Typically, fenestration meeting performance

recommended for 50-100 year institutionalbuildings.

• No water penetration when tested at 12 psf,

• Maximum air leakage rate of 0.1 cfm/ft2 when. ,

• U-factor of less than 0.30 BTU/(ft2 hr °F)

• .

factor is less than 0.25 (very small overhang oreave)

• Condensation resistance factor no less than 53

Window Leakage From



Window may be underdesigned for expected

.

Standards for Construction



Standards for Construction

ASTM E2112

an ar rac ce or

Installation of ExteriorWindows, Doors,

The standard assumes that the basic designof the building’s water-shedding system isadequate, that is, that either (1) there is a high

probability that the outermost buildingsurface will dependably prevent all water

,incorporates an effective concealed barrier

that will dependably prevent further intrusionof incidental water that breaches the

outermost surface.”

Window Leakage From



Leakage occurringfrom open seams in

from missing internalseals can discharge

sealants are placedtoo far forward on theassembl .

Window Leakage From



Deficiencies in window joinery can lead to water

.

Extrusion Ca s and Closures



Extrusion Ca s and Closures

Window perimeter sealants and jamb flashings cannot.





Section and Detail Conflicts

Sometimes two adjoining section details can look

adequate until you project them together into three.

Transitional Conditions




What happens when sections transition




a s t o a Co d t o s

Unless WRB is put in alignment in

o e or zon a an ver ca

planes, leakage may ensue.







Storefront vs. Curtain Wall



Storefront vs. Curtain Wall

Location of perimeter sealants can prevent waterpene ra on o e n er or ue o a e ec n a w n ow.

Storefront Curtain Wall



• By design, brick veneercavity walls will allow water

• Excessive water

penetration can lead tolong term problems such

,efflorescence, decreasedthermal performance anddamage to flashings, wallties and other materialsw n e cav y

• Both material propertiesand installation proceduresinfluence the amount of

Masonr Com atibilit



• Bond between mortar and brick influenced by

brick.

• The Initial Rate of Absor tion is the brick’s initialsuction of water from fresh mortar.

• Water retention is the mortar’s ability to hold onto water.

Masonr Com atibilit



• Universit desi n uidelines re uire wood moldbrick, which typically have a higher IRA

Initial Rate of Absorption Range of Brick Portland or Blended Cement: LimeMortar

Mortar CementMortar

Masonry CementMortar

Up to 10 g/min/30 in.2

(Up to 0.0005 g/min/mm2 ) (Type N) (Type N) (Type N)

10 to 30 g/min/30 in.2Type N or S Type N or S Type N or S

(0.0005 to 0.0016 g/min/mm2 )

Above 30 g/min/30 in.2

Type N

(Type S)(Above 0.0016 g/min/mm2 ) __2 __2

Dry when laid

2 .Type N

(Type S)

Type N

(Type S)

Type N

(Type S)(Above 0.0016 g/min/mm2 )

Wetted prior to laying

1 Alternate Types listed in parentheses

2 Not recommended unless verified with testing

Masonr Com atibilit



Mortar Average Compressive

Strength at 28 days, min, psi

Water

Retention, min,

Air Content,

max, %

Type N Cement-

Lime

750 75 14

Cement

Type N Masonry

Cement

750 75 20

Masonr Com atibilit



Low Water Retention

High IRA

Mortar stiffens rapidly

resulting in bond line

separa ons

Masonr Com atibilit



High Water Retention

Low IRA

Little water is absorbed

into brick resulting in

on ne separa on

Masonr Com atibilit



Water Retention

Com atible with IRA

IRA Compatible with

Good Mechanical Bond

Achieved



Brick IRA:

oTested in accordance with

ASTM C 67 and BIA FieldProcedure

20 drops in quarter sizedcircle, if absorbed in

oIf too high preconditioningwill be required

un er secon s, s

over 30 g/min/sq in.

Left figure from:http://www.masonrysociety.org/Masonry%20Lab/Lab%201/Lab-1-IRA.html

Right Figure from BIA Technical Note7B “Water Penetration Resistance – Construction and Workmanship”

Masonr Com atibilit



Mortar Water Retention

• Tested in accordance with ASTM C1506 and C

270•

gradation

• Increased fines will increase water retention,

rovided that the radation is still within ASTM C

144• However, excessive fines can lead to shrinkage

cracks and higher water penetration rates

Masonr Com atibilit



• Installation proceduresa ec wa er pene ra onrates

•Preconditioning should bemonitored

• Head and bed jointsshould be full

• Retempering of mortar isacceptable provided mortaris used within 2.5 hours•Figure from BIA Technical Note 7B“Water Penetration Resistance – Construction and Workmanship”

Masonr Com atibilit





• Once materials andinstallation procedures have

,should be constructed

• ASTM C 1601 testing shouldbe conducted to verify waterpenetration is not excessive

Masonr Com atibilit



Mocku s and Qualit Assurance



•Mockups should includerepresentative samples of all building

.

•Exterior Cladding

•Back-up Wall,•Fenestration

•Roofing,

•Weather Resistive Barrier

•Flashings,

• er ea er es s veComponents.

•Requiring performance testing onmockups sets standard for expectedworkmanshi and allows time tocorrect problems before componentsare installed in building.

•QA testing ensures expectedperformance is met on components

Wh is A Testin Im ortant?



• It is ALWAYS easier to fix awaterproofing problem

on a building.

find out about a problembefore the cladding goeson a building.

• It is ALWAYS better tohave the Contractor f indhis own roblem beforethe Univeristy does.




Masonry and Flashing

• ASTM C 1601 – Determines how much

masonry veneers

• ASTM C 1715 – Evaluatesperformance of masonryflashing systems

• –

Evaluates performance offlashing laps




Fenestration Testing

– .Specification for Field

Testing of Windows and

• ASTM E1105 – Evaluateswater penetration

• ASTM E783 – Determinesair leaka e throu hwindows

• AAMA 501.2 – Evaluates

resistance of curtain wallsand storefronts



• ASTM C 1193, AppendixX1 – Field test to adhesion

Mockups and Quality Assurance



-

• Pond Testing

• Interface Testin

• Hose Testing

uestions ?



Whitlock Dalrymple Poston & Associates, PC

335 Greenbrier Drive

Suite 205

ar ottesv e,

434-245-6117

www.w pa.com

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Why Buildings Leak UVA