Water Management in Commercial Window Systems

Ritz-Carlton HotelSt. Louis, MO

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Course Learning ObjectivesAt the end of this course you will be able to:

• Discuss the ways water penetrates a building envelope.

• Explain the basic concepts of water leakage.• Describe good practices for preventing water

leakage.• Explain how the basic principles of protecting

walls against water leakage also apply to windows.• Describe how various wall types – punched, ribbon

and window walls – can be detailed to minimize water leakage.

• Discuss various strategies for ensuring that specified performance is achieved.

Water Management in Commercial Window Systems

Module 1• Why talk about this?• How does water

penetrate the building envelope?

Ritz-Carlton HotelSt. Louis, MO

Why talk about this?• DPIC Study

– 3700 claims– Top reasons for

lawsuits against architects

• Roof problems (10%)

• Wall problems (9%)

• HVAC (7%)

• Floors (6%)

Source: Architectural Record, August 2000

Percentage of Lawsuits due to Building Envelope Failure

Purposes of Installation Systems

• What purposes should a window installation system fulfill?

Purvine HallOregon Institute of Technology

Purposes of Installation Systems• Secure attachment• Limit air & water

infiltration• Limit structural

deflection• Allow for expansion &

contraction

Purvine HallOregon Institute of Technology

Principles of Water Leakage

• What three conditions must exist simultaneously in order for walls to leak?

Speculative Office BuildingChicago, IL

Principles of Water Leakage• Rain water is on the

wall• Openings exist thru

which water can pass• Forces are present to

drive or draw the water inward

Outdoor Test FacilitySouth Florida

Preventing Water Leakage• What are some

design principles you use to minimize water leakage in the buildings you design?

Buckner Wellness CenterMarshall, MO

Preventing Water Leakage• Barrier wall

– thin wall system– relies on a perfect seal– intended performance is

seldom obtained– seal affected by man &

nature– reliance on single seal

major cause of water leakage

Preventing Water Leakage• Cavity wall

– exterior wall & back-up wall

– 2 lines of defense against water infiltration

– interior seal protected from the elements

– eliminate pressure differential

Preventing Water Leakage

• Rain Screen Principle– Goal is to eliminate

pressure differential– Essential elements

• exterior rain screen• interior barrier which

prevents passage of air & vapor, protected from water

• confined air space, open to outdoors, drained to outside

AirSpace

Air/VaporSeal

RainScreen

Preventing Water Leakage

• Examples of Rain Screen principle in practice – Brick cavity wall– Aluminum curtain wall– Casement design Casement

Rain Screen

Air Space

Air / Vapor Seal