Joists in crawlspace wet/moldy

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Old 06-24-13, 01:36 PM
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Joists in crawlspace wet/moldy

Hello,

We noticed today that a couple of joists in the crawlspace near the foundation wall are wet. There is a white substance on the joists which could be mold? I will try to get some pictures soon (its 93 degrees and raining right now). I did not go into the crawlspace to check out the rest of the joists due to not having the proper mask on hand. The crawlspace is under an addition that has foam insulation boards and vinyl siding. I was in the crawlspace a month ago and did not notice this but I'm not sure if it was wet back then too. The crawlspace is unvented and connects to my basement. The floors have fiberglass insulation and there is foam board insulation on most of the crawlspace walls.

The crawlspace walls are block with stucco. The floor is cement. I do not believe there is any burst water pipes to cause this. I do know that the gutter is clogged and I am trying to have someone come out soon to remove the debris.

1) Do you think the clogged gutter could cause water to somehow get into the crawlspace and make the joist wet, or is it a more long term issue?

2) Any other thoughts on what could cause this?

3) What can I do in the short term to dry the wood out asap so it doesn't rot?

4) What should I do in the long term to figure out the cause?

Thanks all.
 
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Old 06-24-13, 01:43 PM
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The first step would be to dry it out with a good dehumidifier. Outside air will be warm and humid so creating a vent might not solve the immediate moisture issue. Then address the source which may be related to the gutter or may simply be moisture vapor passing right through the concrete.

Covering the crawl space floor with a vapor barrier and sealing it to the walls would help to eliminate the moisture.

Bud
 
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Old 06-24-13, 02:07 PM
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Can I get a regular dehumidifier from home depot? Would the mold make the dehumidifier unsafe to use for other purposes later? Thanks.
 
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Old 06-24-13, 03:07 PM
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Nothing that couldn't be cleaned up. For use at low temperatures (not low now) they make special units, but my guess is an above the bottom unit from a big box should be fine. Be sure to drain the water to the outside.

The mold can be easily washed off for use elsewhere.

93 and raining sure makes for happy mold. Pick up a humidity/temp meter as well to track your progress.
 
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Old 06-24-13, 03:22 PM
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You also mentioned that you have fiberglass insulation between the joists. Does it have a foil or kraft (paper) face? And if so, is this face on the top or bottom of the insulation. While probably not a root cause, given that the space is insulated, and there is presumably some heat in the winter, if only residual from the basement, the vapor barrier should be installed on the warm side of the insulation, so could have some affect if installed with the face on the bottom.
 
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Old 06-24-13, 05:59 PM
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I am not sure if the fiberglass is faced. Its not faced towards the crawlspace. It could be faced towards the warm side (the rooms above).

I will try to find a decent dehumidifier and run a hose to the outside through the hatch door. I'll drill a hole and put the hose through the hole and caulk the hose.

I will also try to investigate the source of the water more and try to get some pictures. Thanks all.
 
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Old 06-24-13, 07:51 PM
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Going to also treat those floor joist and subflooring. If fungus sets in it can destroy the wood.
It get's treated with a product like Timbor or Bora-Care.
Any exterminating company can do it for you.
 
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Old 06-25-13, 03:41 PM
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I went in today and did some looking around. The crawlspace does not smell humid/musty. There are about 5 joists which are wet all around the same location next to the foundation wall on the side with the clogged gutter (I am having someone over to clean them asap).

I think 3 of the 5 joists do not have mold (yet) but two of them seem to have some mold. You can see the water droplets on the joists. The joists appear to be in good condition. I felt one and it felt damp.

1) Do you guys agree that a clogged gutter could cause this?
2) Should I be worried enough to look under the siding?
3) Do I still need the dehumidifier or will it dry out after the gutter is cleaned? I have a dehumidifier running in the basement that is attached to this crawlspace.

Thanks all. Pictures attached.
 
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Old 06-25-13, 04:51 PM
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Judging by the large wet spot on the concrete along the ground (which tells me water is trapped behind the parged cement), and the water trails coming from the siding, I would suggest that there may be an overflowing gutter there, and a lot of water is pouring down around the window, where it gets behind the vinyl siding. If there is no WRB flashing the wall and/or the parged concrete, you may be getting water in the crawlspace from that... much of it would go behind the parged concrete and get trapped (or wet your interior floor, rim joist, crawlspace), rather than flowing out over the face of the concrete.

You could change the small 2x3 outlet and downspout to a larger 3x4 outlet and downspout that will carry away twice the water (twice as fast) and this might help the overflowing gutter problem.

You could also unzip the siding below the window and see if it's wet there, and if so, look whether there is a WRB and if not, how much damage has it done to the sheathing or siding behind.
 
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Old 06-25-13, 05:03 PM
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The gutter is growing tree saplings lol. Its definitely clogged. Hope to have it remedied soon.

Now the question is... is it normal for a clogged gutter to cause such havoc?

There is foam board behind the siding. Not sure on the flashing. I have never removed a piece of siding before.

What are your thoughts on the joists? Can I let them dry out on their own after the gutter is fixed or should I setup the dehumidifier? Can I clean the joists with concrobium?
 
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Old 06-25-13, 09:30 PM
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It appears the moisture is wicking through the concrete to the sill plate/joists because of the big temperature difference; BSI-009: New Light In Crawlspaces — Building Science Information

1. Fix the gutter

2. Foamboard/canned foam the rims (to air-seal--- unless the rim is covered with thick enough foamboard on exterior to prevent condensation for your location) then replace the fiberglass there.

Gary
 
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Old 06-25-13, 09:33 PM
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Thanks, I will read that article. What should I do to deal with the mold? From the pictures does it look like I can clean it with concrobium? Should I still purchase a dehumidifier and run or will cleaning the gutter be enough?
 
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Old 06-25-13, 09:54 PM
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Now the question is... is it normal for a clogged gutter to cause such havoc?
Yes. And you don't have much overhang to keep it from running right down the siding... or behind the siding, as the case may be. Take a 5 gallon bucket and a long handled 4" putty knife with you when you clean them out. It will be better than tossing the debris in the lawn.
 
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Old 06-26-13, 08:33 AM
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I had someone clean out all of the gutters today.

Lets talk next steps.

1) Do you guys still suggest I buy/run a dehumidifier or can I wait for it to air dry now that the water problem should be solved? (Trying to save money by not buying a dehumidifier if I can but I am willing to do it if its the best thing to do).

2) I have a gallon of Concrobium. I am planning to cut the fiberglass bats that were exposed to the moisture and trash them. Will this be sufficient to clean up the mold that you see on the joists in the pictures above? Concrobium also claims to prevent mold growth and seems to have good reviews.
 
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Old 06-26-13, 09:58 PM
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That looks like a 12" overhang on the gutter side, so there shouldn't be water getting behind the siding there. I'd add to the roof to extend it on the gable ends at the next opportunity.

I expect the water is getting in below grade. Cleaning the gutters out should help get the water away and start to resolve that. Longer runouts on the downspouts would help. Sloping the ground away from the house in every direction should help. Digging up the ground next to the foundation to seal the foundation and install a drain is an expensive last step.
 
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Old 06-29-13, 10:30 PM
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I think the soffits are only about half a foot deep.

The gutters were cleaned. I removed the fiberglass which was wet in some parts. No mold on it but thought I'd play it safe. I cleaned the mold off with Concrobium. I sprayed all the joists and plywood in the affect areas, wiped them and sprayed them again. I left the crawlspace hatch open much of the day Friday and much of the day Saturday. I think the joists are dried out for the most part but I will air it out some more to be safe.

I will post again when I am ready to encapsulate the crawl space properly. Thanks for this article Gary. I did not understand all of it but enough to get a general idea on what I need to do. Sounds like I will need to remove all the fiberglass bats, put poly on the floor and walls, put foam board insulation on the walls and seal the sill plate while allowing some room for termite inspections. All of that will come at a later point but I plan to install weather stripping on the crawlspace door sometime soon.

Thanks everyone.
 
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