Forensic Engineering Investigation Of Leakage At Flanged Windows In Stucco

Abstract

Water Intrusion And Accumulation In The Exterior Envelope Of Wood Frame Structures With Stucco Siding And Flanged Windows Has Been Recognized As A Major Cause Of Damage Characterized By Deterioration Of Sheathing And Framing. Invasive Inspections Of Hundreds Of Wood Framed Structures Constructed In This Manner Have Clearly Shown That The Overwhelming Cause Of Deterioration Has Resulted From Chronic Water Entry Into The Envelope At Window And Door Locations. Substantial Deterioration Has Been Observed In Sheathing And Framing As Early As The Third Season Following Construction With Extensive Deterioration Observed In Many Structures By The Fifth Or Sixth Year Following Construction Manifesting Primarily At Window And Door Penetration Areas In The Envelope. This Study Was Undertaken To Quantitatively Ascertain The Causes Of The Water Entry At Flanged Windows In Stucco Siding Installations And Compare With Water Entry At Wood Windows In Stucco Siding Utilizing Astm E1105-00 Field Determination Of Water Penetration Of Installed Exterior Windows, Skylights, Doors, And Curtain Walls, By Uniform Or Cyclic Static Air Pressure Difference. Effects Of Sealing/Caulking Of The Perimeter Of The Window At The Stucco/Window Intersection Were Also Studied And Quantified Using The Test Apparatus. This Paper Provides A Description Of The Common Construction Conditions And Presents The Quantitative Results Of The Study Of Causes Of Leakage At Flanged Windows In Stucco And The Effect On Leakage Of Sealing/Caulking Of Perimeter Joint.