Flashing Considerations • Temperamental : Just like kids, the adhesives used in self-adhesive flashings have their own personalities and unique behaviors. If you don’t pay attention they can misbehave and create all sorts of headaches. • Cold Weather Application : Many adhesives lose their grab as the installation temperature decreases. The use of a primer can improve adhesion in the cold. Pay attention to manufacturer specifications and be sure the primer you choose is compatible with the adhesive on the flashing. Always test before installing if they are not part of a proven system. • Heat build-up: If you have ever gotten into a closed car that has been sitting in the sun on a 100+ degree day, you already understand the concept of heat build-up. There have been reports of cars reaching temperatures as high as 160° F. Wall assemblies are closed spaces, too, where the interior space can get much hotter than the ambient air temperature. A black wall with southern exposure in a heat-prone area like Phoenix can get just as hot — or hotter — as the inside of that car. Some adhesives like asphalt can’t take that kind of heat, while high-performance adhesives like butyl and acrylic are better suited for high temperatures. • Material Compatibility: Some combinations of building materials do not play nicely with each other and are incompatible. Check the manufacturer’s product information for any installation guidance or limitations. Make sure that the flashing is compatible with all the materials that it will contact. • Seal the Deal : No matter what type of flashing you choose, you’ll need to use a sealant (also known as caulk) with it. This holds true even if the flashing is self-adhesive. Why? Sealant can fill in small voids in the substrate surface, ensuring a complete seal under the window flange without gaps. An elastomeric sealant will keep the window sealed during expansion and contraction due to temperature changes. While it may not be required by all code bodies, it is a definite best practice around windows. The other best practice required by nearly all manufacturers is the use of a J-roller to press the flashing down. This practice eliminates air gaps and ensures a tight bond between the flashing adhesive and the substrate. Many adhesives are also pressure sensitive and require rolling to activate the adhesive. Those short few minutes you take to J-roll that flashing can save you hours of call-back time.
8
Made with FlippingBook Digital Publishing Software