A healthy building envelope works as a fully-integrated system of building components and barrier materials to protect your home from water penetration. Proper construction techniques are essential, especially at key transition points where two or more building envelope components are joined together. Your siding is particularly vulnerable to water penetration at three critical areas: siding to roof transitions; above roof siding transitions and windows.
Water and wind are the enemies of your building envelope. Whether it’s wind-driven rain, water trapped on the roof by an ice dam, or condensation behind vinyl siding, if there is a way to infiltrate your roofing or siding, water will find it. Even the tiniest gap or hairline joint will do.
“Flashing” is a term that describes the materials and techniques used to prevent water from penetrating gaps and joints at transition points. Typical flashing materials include sheet metal and a variety of water-proof and breathable membranes. Critical roofing flashing points include seams or transitions where the roof deck meets above-roof siding, gaps around skylights and vents, and within 6 feet of the roof’s edge. With siding, flashing around windows, doors, and decks prevents water penetration from causing rot, interior leaking, and mold. Flashing is your building envelope’s last line of defense against water penetration.
Proper installation requires experience and attention to detail. Not all flashing materials and techniques are correct for all applications. And most leaks can be attributed to flashing that has failed or was not installed properly to begin with.