Ron Van
Well-Known Member
The subject of crawlspace vents confuses me because there are several companies now that are selling crawlspace encapsulation where they seal the crawlspace.
Sagging floor repair estimate
- Thread starter shan2themax
- Start date
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My guess is that that is because of the installation of a dehumidifier. As I understand it, a main purpose for the vents would be to allow air circulation to keep the space dry. If a dehumidifier is installed, then the vents would actually bring in humidity. That said, a dehumidifier requires periodic maintenance: it needs to be flushed at least every few months to prevent algae accumulation in the water tank/discharge line.
tomtheelder2020
Well-Known Member
At first blush, this seems like a good alternative to vents as a means of keeping wood in the sub-floor dry. It wouldn't make sense where I live (below freezing occurs only a few days a year) but in Ohio freezing air blowing under the floors would be a killer on utility bills. I have two concerns about this system I would like to have someone more knowledgeable address: 1) might humidity from warm interior air condense on the upper side of the encapsulation materials, wetting the wood? and 2) soil under the encapsulation material would become moist, allowing root growth under the house - could that cause problems?
I'm not "someone more knowledgeable" nor am I advocating for the approach, but perhaps my (different but related) personal experience can add to the discussion.
1. I have a dehumidifier in my basement with the floors above temperature controlled with an HVAC system. Perhaps it is NJ weather, or simply because of the drying effect from the HVAC system, but we never had any condensation on the floor above the basement.
2. Even with humidity on the ground, how can plants sprout with sunlight? That said, perhaps you were talking about nearby trees with roots growing to capture the humidity under the house? I can understand that concern but I don't know if it applies to Shan's situation.
tomtheelder2020
Well-Known Member
If there is no vapor barrier between your 1st floor and basement, moisture could migrate instead of condensing on a surface.
Yes, I am wondering if root growth could cause problems. Roots will go where the moisture is. Could roots the size I see raising sidewalks grow under the foundation? Could roots damage the moisture barrier?
I'm finding hard to see how _unmanaged_ moisture would be present, let alone migrate. In the basement, the dehumidifier keeps the air dry if any moisture finds its way in, and the HVAC has a drying effect on the floors above. In fact, during the fall and winter months my wife has to keep humidifiers on in the upper floors so that her skin problems don't flare up because of how dry it is.
Of course, the humidity conditions in Ohio may be different. Still, IMHO it is a matter of controlling the humidity anywhere that it needs to be kept in check.
Got the loan for the sag repair, estimated install of April 10th. Although I am on the list for an earlier install in the event that someone cancels and I can move up the list. I also am doing the bactronix spray to kill mold. I wasn't going to, I was just going to do it myself.... however, I have got to quit kidding myself with some things..... this is one of them. That is supposed to happen on April 7. They will take down all the insulation that is left before spraying.... there isn't much left at all.
Slowly slowly checking things off.
Slowly slowly checking things off.
Ron Van
Well-Known Member
You’re checking off a big one! The foundation and the roof are the two biggies but they both have to be right.
Ron Van
Well-Known Member
You’re getting er done!
