Crawl space moisture

ProbablyBroke

ProbablyBroke

does not torque to spec
Joined
Nov 7, 2012
Location
Reidsville
i am a first time home buyer and currently under contract on a single story, brick exterior, stick built house from 1977. The original owner is a little old lady whose husband has been gone for 6 years, but she has managed to keep the place up pretty well on her own. I had a home inspection done 2/27 and aside from some small nit picky things, this is the only issue I'm concerned with.

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The house sits on a rather gradual hill, and I don't think there are adequate drains and gutter spouts to divert the water away from the house. The vapor barrier is pretty new. I'm sure that the house has settled some in the 43 years as you can find an uneven spot in the floor along the girder. I would imagine that any damage has already been done if it were an issue. Judging by the photos, does this look like an issue that could be solved by French drains and some better water diversion or am I getting myself in over my head?

Any advice or experience is appreciated. I'm already overthinking the situation as it is.
 
Paging @Mac5005 and @moldman05 for the expert opinion.

In my non-expert experience, yes you will do well to improve drainage away from the foundation and maybe monitor the moisture in the crawl. Doesn't require overthinking, just some shoveling. ;)

Congrats on the house!
 
Outside pics of the problem areas would help.

I would say route the gutter downspouts down and away from the house as much as possible. May need a French drain depending on surface water runoff and how it flows during storms.

@Mac5005 knows all about crawl spaces and moisture.
 
The broadside of the house with vinyl sunroom is facing up hill.

Moisture reading was 05.3 on a wooden joist in the crawl space. (I'm regurgitating what I was told)

I'll have to ask about how old the ductwork is.

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It’s obvious the foundation walls have been damp or wet. Is there signs of standing water on soils adjacent to walls ? Picture shows gutters but I can’t tell what happens at termination of downspouts. It doesn’t do any good to have gutters if the water is dumped at the edge of foundation . If the crawlspace has a moisture problem there would be mold growth on wood floor joists and sills. Look carefully above A/C ducts , near center of house and near front door.
Another factor to consider is the temperature the house is kept during the summer. Older occupants tend to keep their house warmer than younger ones . The colder the crawlspace becomes the more the opportunity for condensation and moisture problems. This is made worse by old insulation and leaky duct systems if located in crawl space.
 
That's very similar to my house orientation and the issues in my crawlspace when we bought our house. The previous owner said that the yard settled over 25 years and lost the slope away from the foundation. We had mudlines halfway up the piers but they must have been from a long time ago.

We got the crawlspace encapsulated but haven't fixed the drainage problems at the back of the house, and then the guy behind me clearcut and graded out the natural diversions so we drain his property too. Need to get that fixed as part of the grading for my garage project, as it backs up against the house in heavy rains. My other neighbor just put in french drains about a month ago and that seems to have helped his out a lot. Our crawlspace is regulated to about 50% humidity year round, which has solved all of the insulation sagging and joist moisture issues that were a concern.

Anyway, there should be very straightforward solutions to the things you're worried about, if that makes you more confident. Get the drainage sorted out around the house, and get the crawlspace encapsulated, and you should be in much better shape. You can brick-up those vents after that too, because you aren't going to need them anymore.
If you are going to be doing any HVAC, electrical, plumbing, whatever, it's really nice to have the crawlspace encapsulated because it doesn't feel like a muddy wet crawlspace anymore. Well, except that you're still crawling around under the house, but it's clean and warm enough.

I'm no crawlspace expert, I just want to make you worry less because it doesn't really seem that bad under there. :D
 
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In the bottom left pic of the first post, I was kinda wondering about the circular patterns on the hollows of the block... Is that condensation forming on the inside, against the colder part of the blocks (that have cold air pockets), or outside water leeching thru?

I've had water problems in the basement of my mom's house. Turns out about 80 large (24"+) pines (on a half acre lot) had been cut off and stumps ground down on the lot 15-20 years previous. Stumps had rotted and what should have remained surface water was getting down and then finding it's way to the basement. Some of the old stump holes had started collapsing is how I figured that out. Dug out and packed them with clay fill and that stopped it. That lot being clear and open like that, they may have cut a mess of trees at some point and you have the same issue that's not helping the situation. Our local county GIS system allows you to look at old aerial photo layers in rough 10 year increments. You might want to look back and see if they did a massive tree cutting in the past couple of decades..

Are those downspouts piped? Or is the water getting trapped by those planting areas?

We got rain coming on Tuesday, you may also, might be worth a ride by there and see exactly where the water is flowing, are the gutters overflowing at a low point, etc.

On the last pic of the exterior shots, is that mud staining on the lower foundation (especially left of the hose reel)? As in rain splash? Is that white rock fill new? There might be more water coming off that corner at the roof valley than the gutters can handle, especially since there is not a downspout right there near the corner. It looks like there is a corner splash guard on the gutter to keep the water from overshooting the gutter, but it has a long way to go to get to a downspout.
 
One thing is to get rid of the scalloped edging surrounding the white rock.
It traps water so the house might as well be sitting in a pool when it rains.
If the downspouts dump into it ..... there's your damaging water source.
 
From the pictures,

The efflorescence (white mineral deposits) on the concrete block is indicative of increased moisture in the foundation. Not a huge issue, as this can happen with block wicking the moisture up from surrounding soil.

The brown water Mark is a sign of standing water with some depth. This is a concern.

First try to get gutter/downspout water away from foundation. As well make sure the ground slopes away and can divert water away from the foundation freely.

If this doesn’t work, then an exterior French drain can get the water elsewhere, but requires disturbing the exterior landscape.

Third would be an interior French drain, either partial or full perimeter which may require one or more sump pumps, if it’s impractical to get continuous slope to daylight to evacuate the water.

All of this is somewhat separate from crawlspace wood moisture issues.

It takes a long time for liquid moisture on crawlspace floor to evaporate and then be absorbed by the wood floor structure. This is due to very little heat to aid evaporation.

However, liquid moisture (water) on the ground is a problem as it can undermine the foundation, and create structural issues.

I’m skeptical of a wood moisture content reading of 5%.

The goal when converting to a closed crawlspace with a mechanical way to remove moisture is to have the wood moisture content at 9-11%. 5% is super dry. >19% is a concern, >21-23% is a major concern as wood destroying mold growth (rot) is likely. 30% is saturated.

I don’t know if I have ever seen a vented or closed crawlspace with wood moisture readings that low.

Typically vented crawlspaces this time of year will have wood moisture content % in the 13-19% range, and 19-30% during the cooling season.

Pic of wood floor joists etc and other wood moisture content readings would be beneficial without seeing this first hand.

Be sure to check in the center of the house, the worst spots will be the coldest areas during the cooling season, farthest away from perimeter walls, or shaded from front and rear porches. This is also typically above/near/between the main ducts.

During the heating season, the humidity is typically low, and some drying of the wood floor system is possible.

Pictures of the wood joists can illustrate the mold growth present and give a better idea of wood moisture content throughout the year. What I mean by that, you could get some low wood moisture % this time of year, but the mold growth and wood rot would indicate a moisture problem during the cooling season.
 
I knew I could count on you guys. I'm planning to stop by the property in the next day or so to get a better idea of what I'm up against as well as take some better pictures of what could be addressed. At this point, I could still walk away from the house if it were reason enough to run. We are in the due diligence period and I'm hoping to use this as a point of negotiation, but only if I can avoid shooting myself in the foot with repair cost after closing. I have a good friend who is a drainage and irrigation guy in Charlotte, but I don't know that he's the one to assess the situation under the house. Most any exterior drainage work, we would do ourselves. The presence of red mud sediment on top of the vapor barrier in the below picture is cause for my concern. I included a picture of the mold found in the crawl space during the inspection. It's said to be pretty sparse and light, but I'll get a better idea of how ide spread when I get under there this week.

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If you determine there needs to be work done under the house, like french drains or encapsulation, know to budget 5-10k, for sure. I'm going thru this right now.
 
Yep the biggest problem I see Is the water intrusion/sediment movement.

The black specs that look like black pepper are of no real concern. That’s indicative of 17-19% moisture content. That fungal growth is surface only. That mold feeds only on the sap on the surface of the wood.

The mold to be concerned with is fluffy colonies of any color on surface. Can be white/green/yellow/pink/black/brown etc or brown mold that is feeding on the wood itself. This brown mold is wood “rot”.

I see the picture of the 5.3%. I question the depth of the probes in that board for that reading, and/or location of that probe. My hesitation is probably because I look for the highest MC in the worst areas, not the lowest.

Wood MC below 9% can lead to shrinkage and cracking of interior trim as well as leads to squeaks and pops where the sub floor meets the floor joists. This is because the crawlspace would be effectively drier than the interior conditioned space.

I’m not saying you need to do anything to raise the wood MC. Just elaborating on why 9-11% is ideal. That moisture content is similar to what the wood MC will be inside the conditioned space of the house.
 
Is there a certain amount of infiltration that is expected or acceptable ? I understand the premise of "the drier the better, to the point that the wood doesn't shrink" . By the end of the week, I intend to present a list of repairs to the seller and realtor that I feel need to be addressed before closing. I think I am unrealistic to expect them to take on the cost of an encapsulation, but in the wake of my grandfathers recent mold remediation on a home of similar age, I'm paranoid that I'm inheriting someone else's moisture issues. I imagine the most reasonable thing to do is consult an expert to go onsite. The home inspector didn't seem particularly concerned with the amount of moisture, but it's his payday, not his savings and mortgage.
 
That crawl space actually seems to look pretty good compared to others I’ve seen.

Scott is the expert. I’d listen to him.

But by looking at the pics, I’d think some piping to move gutter drains away from the house will likely solve 99% of your issues.

I didn’t see any cracking in the pics. No “bad” mold appears to be present. And your lay if land doesn’t appear to have excessive surfface water run off towards the house.

the tank under the house is reasonably new and could be because the last one ruptured and flooded the crawl space, thus causing the water lines you are seeing. I’d be willing to bet the water lines from what looks like flooding and the effolorescense on the CMU are unrelated.

I am no expert and haven’t seen it in person, but by the pics, that would be my guess.
 
Is this piping system change from brass to pex to whatever the valve material is, to galvanized, and then to copper? Is there a dielectric Union there? Can’t tell from the pic and the piping looks reasonably new. If there isn’t one, it won’t be long before the crawl space floods again.

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ProbablyBroke said:
Is there a certain amount of infiltration that is expected or acceptable ? I understand the premise of "the drier the better, to the point that the wood doesn't shrink" . By the end of the week, I intend to present a list of repairs to the seller and realtor that I feel need to be addressed before closing. I think I am unrealistic to expect them to take on the cost of an encapsulation, but in the wake of my grandfathers recent mold remediation on a home of similar age, I'm paranoid that I'm inheriting someone else's moisture issues. I imagine the most reasonable thing to do is consult an expert to go onsite. The home inspector didn't seem particularly concerned with the amount of moisture, but it's his payday, not his savings and mortgage.
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Evidence of standing water is not acceptable. Evidence of washing of soil is not acceptable.

Water intrusion is completely separate issue from crawlspace moisture issue(s).

Crawlspace moisture is from humid air entering the foundation vents, and moisture in that air condensing on joists, ducts, and other substances below the dew point in the crawlspace. This leads to moisture contents going above 23% and growing the mold that is wood rot.

Water intrusion whether surface or subsurface can undermine the foundation and cause settling and other foundation structural issues.

Pm me the dimensions of the house. I’ll shoot you back some rough prices. Not a quote but to give you and idea of what we would charge for different things.

If the water Mark is from a leak, or from water intrusion shouldn’t be too difficult to determine.

Most inspectors won’t give you an honest accurate opinion because they are hiding from liability and don’t want to beheld accountable for what they say, or don’t.

Find someone that works in each discipline to determine causes and resolutions.
 
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ProbablyBroke said:
@rockcity can you elaborate on what would burst or leak? I'm not familiar with building code or plumbing .
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The galvanized union does not appear to be dielectric. Which means it is not protected from galvanic corrosion when it is connected to the copper pipe. Most dielectric galvanized unions have copper on one side and steel on the other with an insulating material between them. The one I pictured does not appear to be this type. It may be fine, but maybe not.

galvanic corrosion, in this case, happens when two dissimilar metals (copper and steel) are piped together without the proper insulation between them. Galvanic corrosion then occurs, thus shortening the lifespan of the fittings, sometimes drastically depending on conditions and circumstances.

most AHJs require some type of protection against this (dielectric unions, brass nipple, jumpers, etc)

this tank replacement was likely performed without a permit, so there was no inspector to inspect.


The piping may be ok. It’s hard to tell. It just looks very suspect. I’d ask the home inspector about it, he should be able to pick up on things like this.
 
rockcity said:
Is this piping system change from brass to pex to whatever the valve material is, to galvanized, and then to copper? Is there a dielectric Union there? Can’t tell from the pic and the piping looks reasonably new. If there isn’t one, it won’t be long before the crawl space floods again.

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I’m hoping that’s a grey plastic union to join copper to Pex
 
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