New Window Flashing Products Prove Challenging, According to Building Risk Expert Stan Luhr
Leakage claims continue despite widespread use of newer flexible flashing systems designed to eliminate leaks, but building risk expert Stan Luhr of AxisPointe believes more attention should be given to the installation rather than the products to cure complex waterproofing challenges
Salt Lake City, UT (PRWEB) November 14, 2011
Window leakage claims continue to plague homeowners and frustrate builders, despite wide adoption of more expensive self-adhered flashing (SAF) products specifically designed to prevent such leakage, according to nationally recognized forensic expert Stan Luhr.
The problem isn't with the new products' flexibility or adhesive qualities, according to Luhr, CEO of Utah-based AxisPointe, a risk management services provider. Luhr has investigated hundreds of window failures across the country, and claims that installers place too much faith on the products. "It's all in how the products are being installed," says Luhr.
Dozens of SAF products are on the market, including brands from Grace, DuPont, Fortifiber, Protecto Wrap and others. Luhr says the products work well when installed properly, but other factors must be considered when trying to make a building weatherproof, particularly in recessed window designs common in the west.
"A recessed window should be treated like a roof with a window opening very close to the deck surface, and that is why it is problematic for some builders," Luhr said. Luhr's forensic business includes testing windows and solving problems for builders and insurers before they get out of hand. When problems go unresolved, litigation often follows, leading to frustrated homeowners and expensive lawyer battles.
Luhr claims that most leaks occur due to the following reasons, which can be easily corrected during installation:
Improper clearance to window. Recessed windows, particularly in stucco designs, often lack sufficient room to allow the SAF products to terminate vertically, above the finished stucco or brick sill. This results in a 'bathtub effect', trapping water in the system where it finds its way through the slightest hole and into the building. Luhr recommends elevating the rough window sill at least 4-inches above the horizontal shelf to allow sufficient vertical termination of the membrane and clearance to the window sill product. Window offsets less than 6-inches should require the window to be installed after the sill is waterproofed.
Leakage at Flashing Product Lap Joints. SAF products stick together very well, giving a false impression that a seam is entirely waterproof when it isn't. Luhr says that the primary leakage is at the recessed window sill, where multiple pieces are joined together or when wrinkles occur at splices. When products are installed at inside corners and 90-degree joints, small openings can occur which allow water to travel through.
Complex Inside Corners. Many popular SAF products do not flex and stretch around three-dimensional corners, requiring the SAF to be cut and spliced. At inside recessed corners, Luhr insists that a folded corner-not a spliced corner-should be installed. Folded corners are created by folding the product into the dimensional shape which results in a completely waterproof joint.
Outside Corners. SAF products must be cut and spliced to lay flat, creating a pinhole where no protection exists. Luhr says that despite manufacturers suggesting use of a corner piece (often called a "bowtie"), leakage still occurs. Luhr prefers products that can completely cover the outside corner, such as DuPont's FlexWrap™ which stretches and can be installed around corners without cutting.