Hello,
I Moved into a new house about a year ago. Recently I noticed that the crawl space under part of the house gets damp around the edge.
The crawl space is about 2 feet high and about 20 feet by 20 feet. It has 3 edges that are exterior and one that is against the other part of the house. When I went in to the crawl space I noticed that it is quite damp around the edges and dry in the middle of the floor. There is no insulation of any kind in the floor or above the foundation. The house is located in New Hampshire for climate.
My question is what is the best way to dry out the space and keep it dry. I would prefer to fix the problem and not have to run a dehumidifer.
Replies
Unless the soil is muddy/boggy wet, this is not an abnormal situation. The floor of the crawl should probably be covered with plastic, to reduce the amount of moisture getting into the house, but likely nothing else is needed.
As to insulation, yeah, there should probably be some in the floor.
Londor
Do you have gutters on the house?
do downspouts enter the ground to a drain tile or dump out on the surface?
Does the ground around the foundation slope down and away?
was there a period of rain before you checked the crawl?
There was no rain and the house has no gutters. My worry is that the wood part is wet as well and not just the concrete.
What do you mean by "the wood
What do you mean by "the wood part"?
And is this crawl enclosed (and presumably open to the basement), or is it vented to the outside?
the wood part refering to the joists and plywood. It is vented to the outside only. Not open to the rest of the basement.
Any wood should be well above ground level and should not get wet. If it's getting wet you need to investigate why. It may be you have leaks in the roof or siding. Or, in colder weather, the moisture can be due to condensation from moisture in the inside air.
What is above this crawlspace? Is it a regular room or a "sunroom" or what? Why is its foundation separate from the rest of the house?
And why is there (apparently) no insulation?
Normal rooms and no water coming from above. Ive only noticed the moisture in the cold months but have not checked in warmer months. The floor is about 2 feet above the dirt. I assume it was an addition to answer why its seperate. And no idea why no insulation. Looking for tips and advice to fix or what could be causing it.
Give us a description:
You have soil.
There is a foundation wall. Is this poured concrete, concrete block ("CMU") or something else? How tall is the wall? (How far above soil level is the wood resting atop the wall?)
On top of the wall there should be a treated wood "sill plate".
On top of the sills plate should rest the ends of your floor joists.
How could the wood be getting wet? Some moisture will "wick" up through the concrete, but that should only (at worst) get the bottom of the sill plate wet. (And the sill plate, if made, as it should be, of treated wood, should be able to stand being a bit damp.) The joists should not get wet. So where do you think the water could be coming from?
I was thinking it may be condensation from the cold air outside and warmer air in the crawl space. My other guess is vapor coming up from soil. It is build as you describe. PT sill plate doubled up then joists on top. Wall is about 16" to the bottom of the joists. I dont see any standing water or any leaks. Nothing above it is wet at all. Seeing it only on the edges made me think condensation.
Yes, given the layout you could have moisture rising out of the soil and condensing on the cold rim joist. This would be aggrevated by the lack of insulation. You also could easily have moist air from the house descending into the crawl and condensing.
The first step would be to cover the soil with plastic, ideally securing/sealing to the sidewalls using caulk as an adhesive. Next would be to get some insulation into the floor, so that the crawl is kept cooler and less apt to cause soil moisture to evaporate.
If the problem is moist air descending, though, you have a bigger task ahead. First make sure that the room above (if heated by forced air) has adequate "cold air" returns, so that there isn't pressure in the room forcing air out.