New construction, roof sheathing on with ridge vent openings, but not shingles, water resistant flooring down. Roofers delayed. Rain storm brings water onto floor and into crawl space and now have mold in crawl space. Already decided to temporarily cover ridge vent openings in future? Need suggestions about how to seal seams in flooring for next house so it doesn’t happen again.
Thanks
Hover's smartphone app offers an easier way to get precise 3D scans.
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.
Start Free Trial NowGet instant access to the latest developments in green building, research, and reports from the field.
Start Free Trial Now
Replies
Tarps?
Even if they leak a little they ought to help keep crawlspace from becoming a pond.
I'd avoid trying to seal subfloor seams though, that may cause problems later.
Montana,
We always felt the ridge vent cut and let the roofers cut it out. If there is going to be a delay for the roofers we double felt with 30#, ie 18" lap. Might be a few drips but no real leaks.
KK
Keep Vapor Barrier Rolled Up
My son and I encountered the very same wet crawl space problem. For us it was the super wet spring of 2014, when we were building a craftsman-style 1.5 story bungalow. We layed foundation block and followed with crawl space vapor barrier, lapping it 6" up the inside wall. We glued/fastened 4" of foam boards to the inside of this wall. We kept the vapor barrier ROLLED UP. We reasoned that this method would allow rain water to seep through the crawlspace gravel into the ground. That worked for a while. We kept a large fan running in the crawl space, with the access hatch left open, so that there was some movement of damp air from the cspace into the open house.
However, the complexity of field framing the habitable attic meant that we were without a roof for 2+ weeks. I tried sealing all attic subfloor joints with caulk, but that did not work well. Next I tried mesh tape and thinset. That worked somewhat better.
The long and short of it is that keeping the crawl space vapor barrier folded up until the building was fully enclosed, helped alleviate a potentially serious mold problem. To be absolutely sure no problem would develop in the future, we did a chemical swipe/cleaning from within the crawl space. We have had no complaints from the client....knock, knock.
Here's another suggestion: try rolling liquid vapor barrier material (a paste-like mterial used as water proofer in tile applications) onto all subfloor joints. The stuff is expensive at roughly $50/gal. Your OSB subfloor is factory-treated for moisture resistance, so you only need to treat subfloor joints. Keep two large squeegees handy and make sure that you have provided a few exist holes (exterior doors for instance) through which you channel the water.
lapping cs vapor barrier and nailing it down
I want to talk about securing crawl space vapor barrier. Ours came in 8 mil thickness and was 8' wide. It was laid on an 8" bed of pea gravel. We overlapped joints 4". We used 12" aluminum spikes and large-head plastic washers to tightly nail down overlapping sheets. Then we wiped off and taped all joints. I recommend waiting with this task until all subcontract work is done. Anyone wish to comment?