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Water damage in crawl space, need help

JeffPackard's picture

We discovered a few months ago that the floor in two opposite corners of our house had water damage. I went under the house and found that the rim joists were rotted out to go with the flooring damage due to water damage. We've been trying to fix the problem (on a budget) and I need some help. We never have standing water under the house unless we get a horrific downpour, and those are rare. Given that I'm wondering if the water source could be outside ground water as I would think it would settle at floor level and rise if the crawl flooded to reach the joists and flooring. Since that isn't happening, I'm then wondering if the source is more of a high humidity issue (the vapor barrier the builder put down sucked and had to be pull out when I did repair work to the joists), or could it be just from hydrostatic pressure? Any thoughts would be helpful, thanks. 

How far are the rim joist (post #215223, reply #1 of 10)

How far are the rim joist from the ground? Unless it's right on it I'd say you have a leak above the rim joist leaking down and over into the wood.

Florida Licensed Building Contractor, 50 years experience in commercial remodeling, new homes, home remodeling and repairs and all types building maintenance.

It's a 4 block crawl. Not (post #215223, reply #3 of 10)

It's a 4 block crawl. Not even close to the ground. The exterior grade had been up to and partially covering the first row of brick but we've since dug that down. Still need to regrade but trying to figure out the moisture first. 

If you've got the floor (post #215223, reply #6 of 10)

If you've got the floor rotting as well as the rim joists the water has to be coming from above. No amount of water vapor in your crawl space would cause that. It's possible that  your outside grade being so high could have done it but only if the 2 opposite corners were both graded high. I would still look for a leak above the floor. Have you taken the corner trim off to look there? Is there a water table over the rim joist? Is there flashing over the water table and is the top of the flashing behind the water barrier? Oftimes the exterior won't show anything that looks like a leak. In those cases I've found a high pressure nozzle on the hose will show up leaks you can't find otherwise. 

 

Pictures would be a big help.

Florida Licensed Building Contractor, 50 years experience in commercial remodeling, new homes, home remodeling and repairs and all types building maintenance.

florida, (post #215223, reply #7 of 10)

I have repaired more than a few houses where the crawl space humidity rotted joist and flooring. Not enough ventilation and dew point was occuring on the subfloor because of AC.

KK

So have I. I was shown a (post #215223, reply #10 of 10)

So have I. I was shown a crawl space once where the mold dripped from the joist to the floor and the floor was as green as my lawn. But, I've never seena crawl space where only 2 oposing corners were wet  enough to rot the floor above.

Florida Licensed Building Contractor, 50 years experience in commercial remodeling, new homes, home remodeling and repairs and all types building maintenance.

It could be any number of (post #215223, reply #2 of 10)

It could be any number of things. 

Very often the soil outside the house is simply too high, such that it contacts the rim joist.  Unless the joist is made of treated lumber with a ground-contact rating it should never be allowed to come in contact with soil.

The moisture level in the crawl can be too high, due to lack of ventillation and lack of an adequate vapor barrier on the floor.  This will cause untreated lumber to rot.

Often untreated rim joists are set atop a stone or concrete foundation wall, with no provision for a moisture barrier between them.  Moisture wicks up through the stone/concrete and into the wood.

Normally if you have a one-off event of wood being wet by rising water, and the water recedes in a few hours, there will be no damage aside from staining and perhaps some warping.  But if the situation occurs again and again, or the moisture does not clear out rapidly, you can have more serious damage.


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It's a 4 block crawl. Not (post #215223, reply #4 of 10)

It's a 4 block crawl. Not even close to the ground. The exterior grade had been up to and partially covering the first row of brick but we've since dug that down. Still need to regrade but trying to figure out the moisture first. 

Jeff (post #215223, reply #5 of 10)

Is this house full brick or partial with siding above?  Any window ?

do you have a picture of the area you can post here?

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Need pictures (post #215223, reply #8 of 10)

As mentioned above, this could be caused by a number of factors (we clean water damaged homes all the time) so you will need to provide some pictures at the very least. Might be best to find a contractor in your area to take a look at it, things like this are best resolved sooner rather than later as the damage can quickly spread.