Working in Rehoboth Beach, Del., Patty McDaniel of Boardwalk Builders is never far from the salt spray of the ocean. Her crews contend with heavy moisture and wind-driven rain year round.
“I have a very fast feedback cycle,” McDaniel says. “If I make a mistake, I usually know about it after the first good rain.”
Though not every remodeler works in such an unforgiving climate, everyone can learn something from the best practices of those who do.
FIRST LINE OF DEFENSE It's important to understand that siding is just the first line of defense. Proper flashing at seams and penetrations and a well-installed moisture barrier are essential components, without which the installation is almost certain to fail. Eventually, experts say, water will find its way past siding, no matter the material, and through seams around windows, doors, and penetrations such as vents.
“The siding's job is to look good,” McDaniel says. “It's the flashing and the weather barrier's job to keep water out.”
Because the layers between the siding and the sheathing must be properly installed to secure a house from moisture, best practice requires that old siding always be stripped, even when working with vinyl designed to be installed directly over wood. Gino Streano of Lifetime Remodeling Systems in Portland, Ore., says he would never risk relying on another contractor's flashing and moisture-barrier installation, especially given the poor quality of construction he finds in more recently built houses.
“New construction in the '80s is about when it starts,” he says. “For whatever reason, installation just hit the toilet. I would say 95% of the time, if not more, the siding has been improperly installed — whether it's gaps caulked over, over-nailing, nailing too close to the corner of the siding, improper flashing, or even not using flashing on windows and doors.”
New siding applied over existing also stands proud of window and door trim, creating a difficult joint to protect, McDonald says. Once the old siding is off, the flashing and moisture barrier go on, and it's at this stage that many installers make crucial mistakes. The first essential, Streano says, is to never tear off more old siding than can be replaced the same day. Leaving a portion of wall exposed to the elements can sabotage a job before it's finished.
The most important rule — one that is often ignored — is to lap every piece of the moisture-protection system, starting from the bottom up.
“You have to think like water — following the logic of the path of water and the way it's going to get in through what you're building,” says Joseph McKinstry of McKinstry Construction in Seattle.
Each overlap should be several inches long. In climates where heavy wind and rain are common, experts recommend overlaps of about 6 inches at horizontal joints and 8 inches to 12 inches at vertical joints.
MOVING WATER “You're always thinking of shedding water,” says Marty Schirber, of Castle Building and Remodeling in Minneapolis, Minn. “You're always thinking of moving the water away from the building.”
Though the logic seems simple enough, plenty of installers get it wrong.
“That's my main rule,” McDaniel says. “Everything goes on lap-shingle style. I've never seen anyone put shingles on backward but I've seen people make all kinds of mistakes putting on weather barriers.”
Proper lapping is also essential when flashing around rooflines, doors, and windows, vulnerable areas where leaks most commonly occur.