A GBA reader named Jason is seeking advice for a permanent wood foundation (PWF) that’s been subjected to ponding surface water and is now leaking.
The original dampproofing appears to be an asphaltic material that was sprayed or brushed on when the house was built in British Columbia 40 years ago. Located in climate zone 7A, the structure has a fully developed basement, insulated with R-20 fiberglass batts between the 2×6 studs, protected with what Jason describes as a “light” vapor barrier, and finished with drywall. There’s no sign of mold, but there are indications that water has been seeping through the seams of the sheathing on the outside of the foundation wall.
“The water ingress appears to be from surface water ponding and seeping through the sheathing at both the vertical corner and horizontal sheet joints around the back corner of the home where ponding on frozen ground has been occurring,” Jason writes in this recent Q&A post. “Initial interior inspection with drywall removed in the fall observed dampness over entire sheathing surface below grade, but the insulation wasn’t saturated and there are no signs of mold on the drywall. The vapor barrier was intact.”
He adds that a perimeter drain appears to be working, taking accumulated water in the wall cavities and directing it to a drain sump located in the basement.
In addition to dampproofing and joint repair, he’d also considering installing an underground roof membrane to direct surface water to a swale that also will capture water from multiple downspouts.
How should he proceed? That’s the focus of this Q&A Spotlight.
Get the water away from the house
“You absolutely must get that water away from the house,” says Kbentley57.
If there isn’t enough of a slope on the…
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