Searching for Clues to Wet Sheathing
Buster found a deal, a 6-year-old beach house in Washington state. He picked it up in an online auction and has plans to turn it into a retirement home something in the next 10 years.
More on sheathing
It sounds ideal, except for a “very sad surprise.” When Buster went to replace some brick molding around a door, it looked as if the Tyvek housewrap beneath the siding had been installed incorrectly, or was faulty, leaving the OSB sheathing saturated.
In doing a little sleuthing in the area, Buster has discovered there are apparently other houses with much the same problem. And in speaking with contractors along the coast, Buster says he’s been told the housewrap is the problem.
“They ALL say Tyvek is crap since it does not ‘breathe,’ holding moisture in,” he writes. “Now, my dilemma: What do I do now? Does anyone know of a suit against this product? Is the contractor liable at all?”
Hold the phone, Buster, it’s not the Tyvek
“I think you’ll find that the installation techniques used for the Tyvek, the windows/doors/other penetrations to be at fault,” Calvin writes.
What’s happened is that water has found its way behind the housewrap, and in a wet climate it’s tough for building assemblies to dry out when the water infiltration–the real source of the problem–hasn’t been addressed, Calvin says.
As to legal remedies, not a good plan. “I don’t know of any class action suits but would be surprised if the pay out would even come close to solving your problem,” Calvin adds. “I would think you’d have to provide product failure (remove all the siding and show the proper housewrap install was done) beyond any doubt and then what would they give you? Another roll?”
A more successful route might be seeing what the builder will do.
No luck there, says Buster. The contractor has folded.
Calvin is right, says evujevich, it’s not the Tyvek at all.
“It can’t be Tyvek’s fault,” writes evujevich, “seeing how there’s millions and millions of homes out there using the product. There are hundreds of building products out there, and it is up to the contractors to figure out how to apply them in their region.”
Understanding the working characteristics of Tyvek might help, DanH suggests.
“There exists **NO** material that is a ‘one way valve’ in that it will pass moisture one direction and not the other,” he writes. “Tyvek is pretty good in that water VAPOR will pass through it relatively easily, while LIQUID water will not, but to the extent that either passes through, it does so equally well in both directions.
“In this case liquid water somehow got behind the Tyvek, and since liquid water does not pass through Tyvek easily it stayed there. The Tyvek did ‘attempt’ to dry things out by letting vapor through, but there was too much water to deal with this way.
“What this says is that some installation defect ‘channeled’ water behind the Tyvek,” DanH adds. “It’s not a failure of the Tyvek to ‘breathe.’
Correct, adds Hokuto. “The real problem is likely the application of HardiePlank directly against the WRB (Tyvek) in a climate where you’re guaranteed to get large amounts of water behind the cladding. Water gets behind the siding, but has no way to get out. The water (or something else) may have also added surfactants that destroyed the Tyvek’s ability to shed water.”
“Tyvek does breathe,” says PaulCP, “but it will also let water in like every other product you don’t install correctly! I hate it when people blame the product for the installation.”
Try a rain screen to let wall dry out
To be fair, Buster’s new home is in a challenging environment, a place where “rain rarely falls vertically,” as he puts it.
And given those circumstances, evujevich suggests he consider a rain screen. Start by pulling the siding off the house, then install pressure-treated 2x2s over the studs and reinstall the HardiePlank siding. Because rain screens separate siding from the sheathing and housewrap, water driven through siding can exit freely, and the back side of the siding can dry readily because of added air circulation.
“Reasoning?” evujevich writes. “Called a controlled rainscreen. Install a J channel underneath…which will collect the moisture that penetrates past the hardyboard.. this way the moisture can run off, plus the walls will breathe even more, alowing the tyvek to do ITS job, and that’s to dryout.
“Problem was entrapment,” evujevich adds. “Depending on the size of the house, this would be a fun weekend job if you ask me… Besides this would be a perfect opportunity to tuck tape any seams, windows, or around the door for that matter.”
Hokuto says that in addition to a rain screen, Buster consider back-priming all of the trim after it’s been removed–even if it had been backprimed the first time.
“IMHO, the best (read: ideal) solution, as several of us have hinted,would naturally be to remove the siding/trim, check out the entire Tyvek installation, let the OSB dry out, install more Tyvek and seal it properly with Tyvek tape (over edges of Tyvek-Tyvek laps) and butyl rubber tape (over Tyvek-nailing fin joints),” Hokuto says.
“Then do a rain screen installation of new siding. Cost a lot? Definitely. But unless you’re able to sort out where the water problem is, and how extensive, you’ll just be delaying the inevitable, and at greater cost later.”