Crawl Space - School Me

[jimreed2160]

If you have water intrusion, you should take care of that. Drainage issues and gutter problems should be resolved. But general dampness in the soil depends on your area and the local soil conditions. Just put down a sheet of plastic and check it in a few days. That is a simple redneck test to see how bad your problem might be.

I had a house up the road from you in Hopewell, VA. It was on an incline and the crawl space went from about two feet in one corner to about seven feet in the back. It was ventilated but the joists were damp to the touch. There were no water intrusion issues. I just bought some thick mil plastic and had a vapor barrier in an afternoon. After a few weeks, the musty smell went away and the joists dried out. Worked for me.

A quick search of the radon map says that you are NOT in a radon prone area. I would not worry about that right now.

 

[JoeAverager]

We're in TN. Plastic ground cover. Insulation between the joists. Insulated ductwork under the floor. Foundation vents that I open in spring when the overnight freezes end and close in the winter right about when the overnight freezes start.

No mold, no smell, warm floor.

Friend here had moisture problem, house built in sort of a flat low area. He did the same but added foundation fan vents. He said it dried it out pretty good. These little fans ran 24/7. He sold the house and moved back up north so I don't know the status of the house today except that it is well kept, occupied and still standing.

 

[Mogana]

Hi, i'm new to home renovation service. I started a course few months back which has been a DIY course mainly. And now i'm noticing my crawl space leaking out moisture due to lack of insulation. So, i am thinking of insulating it myself, though i read a couple of tips share by https://pickmythings.com/crawl-space-insulation/ as a clue to crawlspace insulation but still skeptical about it DIY. But if i have to hire a professional i would spend more and that's another big consideration for me. My question, should i do it myself or hiring a professional best?

 

[glentre]

Am I missing something regarding encapsulating a crawl space in the northern states or in Canada where the frost level can go down 2 to 3 ft or more? If the ground outside the crawl space is well below freezing, it must also be below freezing in the crawl space unless that space is heated. Over time, a foundation wall would be the same temperature as the frozen ground around it and that same temperature would be transmitted to the ground in the crawl space I think unless the foundation wall is heavily insulated. The cost to condition the crawl space in the winter in these regions must be significant. In these cases, wouldn't it be better to insulate the floor as if it were an outside wall and not try to climate control the crawl space below? Having proper vents to circulate air would then be all that is needed, would it not?

Glen

 

[850xpeps]

Am I missing something regarding encapsulating a crawl space in the northern states or in Canada where the frost level can go down 2 to 3 ft or more? If the ground outside the crawl space is well below freezing, it must also be below freezing in the crawl space unless that space is heated. Over time, a foundation wall would be the same temperature as the frozen ground around it and that same temperature would be transmitted to the ground in the crawl space I think unless the foundation wall is heavily insulated. The cost to condition the crawl space in the winter in these regions must be significant. In these cases, wouldn't it be better to insulate the floor as if it were an outside wall and not try to climate control the crawl space below? Having proper vents to circulate air would then be all that is needed, would it not?

Glen

Might as well own a house trailer and deal with frozen pipes.

The insulation around the crawl space going out should stop frost from getting under the crawl space. On older homes with just an insulated wall, the frost will still only enter at a 45 degree angle.

The crawl spaces can get more than enough heat from the furnace and ducting, and you can pipe a small supply into it. Wouldn’t add much if any cost to heating as the heat rises anyway.

I would never build an unconditioned crawl space for someone. I would tell them to find someone else.

 

[finn]

We bought a house with no vapor barrier, just fiberglass bats between the joists and vents in the foundation walls.

It was an unmitigated disaster.

As others said, the warm, moist air would enter the crawl through the vents, and condens because the crawl was considerably cooler than the warm outside air.

The previous owner had replaced the fiberglass a few years earlier and increased the ventilation in a misguided effort to ventilate his way out of a bad situation. I think he made things worse.

There was also heat tape and signs of repairs on many of the water pipes in the crawl, indicating a freezing problem in the winter.

The insulation between the joists was completely saturated. It actually dripped water when we pulled it out, despite being only a couple years old, and the mice apparently loved it.

Pulled all that mess out and put down a simple vapor barrier, two inches of blue rigid insulation on the block walls, and spray foamed the rim joist.

Made a world of difference. Floors are warmer, house no longer smells, pipes don’t freeze.

 

[acer66]

I tried to get away with no crawl space vents but I had to put them in because that was code but I put a vapor barrier in which helped greatly since the red clays stays damp for weeks after the rain stopped.

 

[850xpeps]

I tried to get away with no crawl space vents but I had to put them in because that was code but I put a vapor barrier in which helped greatly since the red clays stays damp for weeks after the rain stopped.

Vents wouldn’t be code if it was a conditioned space because it becomes part of the house.

 

[My Old Tools]

So you encapsulate the crawl space, then you add AC/heat down there, then you add a dehumidifier, then you worry about Radon....I think I'll keep mine ventilated.

 

[850xpeps]

So you encapsulate the crawl space, then you add AC/heat down there, then you add a dehumidifier, then you worry about Radon....I think I'll keep mine ventilated.

Any crawl space I’ve built for someone. Hasn’t required a dehumidifier. I put a layer of poly down and then pour 3-4” of lean mix cement to cap it off. Dry and clean. No sand dust or other ****. There hasn’t been a need, as some haven’t, piped in ax/heat and some have. The radiating heat off the ducting will warm it.

If you don’t heat a crawl space, you can’t remove water underneath the house with a sump pump. I’d rather run a dehumidifier, if that’s an issue, then worry about frozen pipes and other ****.

 

[fsae0607]

We lost the "old house smell"

A lot of older homes built in the 50's here in SoCal have ventilated crawl spaces with no insulation. Then again, we have a warm, dry climate.

Call me crazy, but I actually like that old house smell, with a bit of earthiness from the crawl space air.

 

[Jeepster04]

No doubt I would put down a good plastic, seal it to the block, the insulate the block.