How long can subfloor stay wet under LVP? I recently pulled up some flooring in an upstairs room to replace it (the flooring I had pulled up had also only been down about 8 months) and noticed that the subfloor was pretty significantly wet against an exterior wall. There is no plumbing, condensate drains, etc in that area, just a window above it. I figured we had a flashing issue around the window so I left the subfloor exposed so I could get to the root of the problem. We’ve now hard pretty heavy rains including wind driven rains since early this morning and the subfloor is bone dry with no signs of active moisture intrusion. It led me to thinking if the water was from having our home pressure washed but the last time we had that done was back in October. The spot was under LVP so the moisture couldn’t evaporate upwards through it, but it was at the second floor so I would think that it would still eventually dry still. Looking to hopefully learn something here, but also to be able to finish my flooring so any expertise would be appreciated!!
Was there a vapor barrier under the finished floor?
The vinyl product itself will slow or stop moisture transfer, and then add to that the vapor barrier under it.
If moisture gets under the system, it really can’t evaporate.
No vapor barrier, LVP was just on the raw subfloor. Beneath that is just a layer of insulation I’m sure then the drywall for the ceiling below it (which has a very faint stain).
So it definitely couldn’t evaporate upwards but my gut originally thought it would soak through those layers below and eventually dry out, but the more I think about it got me to thinking if that’s actually the case
I had a job with lvl that got moisture under it the day before. It was summer so it was pretty hot. When I pulled up the floor there was mold already growing under the lvp. And it was only one day from where there was a water leak. I had to pull up the entire floor and dry out the sub floor. Took a few days to get dry. Then I had to install new flooring. I did not reuse the brand new lvp due to the mold growth on the foam backing. It will be best to pull up the flooring. Find the water intrusion point and fix that, before installing the new flooring.
That’s where I’m stumped. Lived here 4 years with no signs of moisture issues there, and now there staining on the ceiling below and a wet subfloor
Trying to diagnose between several guesses:
- It’s a flashing issue that’s always been present but having carpet in the past allowed it to air out and dry, concealing the issue. Once I put down LVP in place of the carpet it trapped the moisture and made the issue more evident
- Pressure washing sprayed water at an unusual angle allowing moisture intrusion that got trapped under LVP and never dried out, even after a few months which I’m curious if that’s possible
- Neither of the above and my dog is peeing in the corner or a plant saucer has a hole in it (neither of those are the answer)
Are there any staining on the subfloor indicating the direction of flow?
Did you check for moisture here?
Also has there been rain in the days previous to the storm you mentioned. The storm you mentioned, may not have been from the direction and wind required to drive water in.
Power washing houses is not a thing around here, but someone would have to really concentrate the flow to drive that much water in, not to mention, it seems unlikely to still be wet months later.
I did and all those areas are dry, and when looking under that baseboard the staining on the base plate is just along the bottom of the 2x4 so it looks like it’s coming along the outer edge of the sheathing and gets caught up at that spot, possibly/probably a seem between the sheathing
My hunch would be the window. A more invasive eval is needed. I wouldn’t disrupt the interior finishes just yet though. Since it’s vinyl, I’d probably pull it off around the window. It would have to be from an ouside source, so your answer should lie there. Don’t just focus on the bottom of the window, remember water will take the path of least resistance and gravity.
I will add that I see a lot of issues at the vinyl siding gable transitions. If you don’t see anything around the window, that would be my next area to look.
Thank you! That transition does look like a probable source as well.
Morning Brian. I find it a hard understanding the thread. Lots of basics you overlooked as well as ethics. Did you inspect the property within the last 12 months?.
Subflooring. What material? OSB, Plywood, Planks, what species of planking.
As for flooring “moist at the outer wall assembly.” There appears to be a failure at the outer wall assembly that must be controlled prior doing any repairs. Windows close by? Hydronic baseboard heating?
Prior laying any finished flooring, the sub flooring most meet the manufactures installation instructions, as well as RH in the air. Wood is hydroscopic. Wood/Flooring takes on moisture from the surrounding environment** . Moisture exchange between wood and air depends on the relative humidity and temperature of the air and the current amount of water in the wood.
As for how long can a subfloor remain wet, again, it depends upon the environment.
I’m finding it hard to understand your response as well. Answers to about everything you mentioned can be found in the original post or the photos include. As far as ethics, do you think I’m gutting a clients home for inspection? I didn’t out right state it but I thought it was pretty clear from the post that this is my personal home. It is clearly stated in the OP that there is a window nearby and no possible source of moisture really other than exterior intrusion.
Oh, you ain’t the only one!
Well, ya kinda did, and I understood that from the very first post.
Most of us figured that out quickly, Brian.
That’s what happens when you actually pay attention to what someone says.
Durability of Wood
In normal use the moisture content of wood varies between 8% percent and 25% percent by weight, depending on the relative humidity of the air. The dependability of wood often coincides with moisture, but that does not necessarily mean wood can never get wet. The most basic of fundamentals of wood remains. Wood is hygroscopic, ‘of a substance’ tending to absorb moisture from the air. Wood will gain and/or lose moisture based upon the conditions of the surrounding environment. In brief, wood will expend and contract.
The fundamentals one should refer to with wet wood and water saturation, the damage that can occur from continued or repeated saturation. When measuring moisture content, ranges between 5 – 12% percent would be considered optimal. Up to 17% percent is generally considered moderately moist and acceptable in some building duties. Any reading over 19% percent is considered saturated and my need to be replace when drywall is attached as a preventative measure against future moisture buildup.
Wood moisture content is measurement by how much water there is in the wood as relative to the wood itself. The measurement is expressed as a percentage of MC or Moisture Content. Two important moisture numbers to the equation are expressed in percentages. 19% and 28%. Fiber saturation averages around 28%.
The natural behavior of wood being hygroscopic is responsible for some problems encountered when wood dries.
Read more at the Canadian Wood Council
Buy a moisture meter.
WAFI / WAFM
STOP Plagiarizing without stating your Source!! Providing a link is always preferred!!