Damp proofing

Do crawlspace foundations need damp proofing or drainage systems?

I've had crawlspaces with sump pumps in them; I've not seen other drainage systems.

Juan Jimenez wrote:Do crawlspace foundations need damp proofing or drainage systems?

Generally not. There are companies out there that specialize in making crawl spaces so clean you can eat off the floor, and they're pretty cool for sure, but probably 90% of crawl space moisture issues have to do with:

1. Surface drainage issues.
2. Improper ventilation.

This message was edited 1 time. Last update was at 12/18/2014 06:12 PM EST

Should they? IMO Yes. Is it required by code? I honestly don't know.

Moisture control should always start from the outside and damp proofing, though a very poor method, is one partial way of addressing that. Anything below grade can collect water and masonry will wick water through to the interior of the crawlspace without some sort of barrier. You can accomplish the same thing using vapor barriers at the interior.

I look at interior and exterior systems as being complementary not mutually exclusive. The main goal is to keep water out if at all possible. If for whatever reason water gets in, the interior system will either collect it or at least prevent it from causing problems.

Living in the land of "wet" we see many with some sort of additional drainage systems, but requiring is not required. See many foundations seeping moisture under the stem wall on top of the footers, could have been sealed to slow it down!

With our rainfall, and areas of hard pack clay soils, we find moisture in most crawl spaces during the fall and winter months as the water tables rise. Sometimes it is simply coming up from the ground and has nothing to do with exterior drainage. This is always costly as they have to put an interior drainage system in the confined space. I wish they would make it a builder requirement to install some sort of drainage system in these spaces, at least in the Northwest. It would be nice to not have to get wet!

Thanks guys. I didn't think it was required, but the code is vague. I even went on a code inspector forum and they debated about it. I just listed it as a recommendation.

It's interesting how Cameron and I live in virtually the same place when it comes to drainage issues and foundation types (and soil types and Radon levels and just about everything else), yet we have different views on it.

Both of us agree it's not necessary or code, but he says it's a good idea.

Cameron- I think they're cool, but just cool. If they're necessary, which I believe is rare, great, but otherwise a wasted expense that is usually sold dishonestly in my opinion.

Do you feel the same?

I have yet to see a crawlspace that has a treatment done to it. Have run into some flooded ones recently that could have benefited from some damp proofing. Needed a boat instead of a krawlgear.

Nathan wrote:It's interesting how Cameron and I live in virtually the same place when it comes to drainage issues and foundation types (and soil types and Radon levels and just about everything else), yet we have different views on it.

Both of us agree it's not necessary or code, but he says it's a good idea.

Cameron- I think they're cool, but just cool. If they're necessary, which I believe is rare, great, but otherwise a wasted expense that is usually sold dishonestly in my opinion.

Do you feel the same?

What do you mean by they're? Encapsulation?

I mean any of these crawl space systems, waterproofing, etc.

Oh good. As you know I have a company that encapsulates crawls. What we do is not dishonest. What we do is help people with their crawlspace issues.

So if you have mold in your crawlspace, where else might it show up?
If you have a wet crawlspace due to the water table, how do you fix it?
When the humidity in the south gets to 90%, how do you keep your crawlspace dry?

A wasted expense is new windows for energy efficiency, solar panels on an inefficient home, installing a 95% furnace and leaving the ductwork from 1988....the list goes on.

bbrinke wrote:Oh good. As you know I have a company that encapsulates crawls. What we do is not dishonest. What we do is help people with their crawlspace issues.

So if you have mold in your crawlspace, where else might it show up?
If you have a wet crawlspace due to the water table, how do you fix it?
When the humidity in the south gets to 90%, how do you keep your crawlspace dry?

A wasted expense is new windows for energy efficiency, solar panels on an inefficient home, installing a 95% furnace and leaving the ductwork from 1988....the list goes on.

I'm sure you sell it honestly, it's also probably a great recommendation more often in your neck of the woods at lower elevations and higher humidity levels than in my neck of the woods or Cameron's.

What I see very frequently here is a high water table being blamed for water issues when it is a surface water issue... "Here's your $8000 solution for bad grading and missing downspouts".

You're an expert, say your piece about how it works in your area. Give us a link to that company as well!

This message was edited 1 time. Last update was at 12/19/2014 07:15 PM EST

Nathan wrote:It's interesting how Cameron and I live in virtually the same place when it comes to drainage issues and foundation types (and soil types and Radon levels and just about everything else), yet we have different views on it.

Both of us agree it's not necessary or code, but he says it's a good idea.

Cameron- I think they're cool, but just cool. If they're necessary, which I believe is rare, great, but otherwise a wasted expense that is usually sold dishonestly in my opinion.

Do you feel the same?

It depends on what you and I are referring to. Based on your exchange with Brad, we're not referring to the same thing. Damp proofing is just a moisture barrier coating on the exterior of the foundation walls. Based on Juan mentioning that, I assumed the drainage system he was referring to was a footing tile. At a minimum I think those should be present but an interior encapsulation or drainage system, while cool I agree, is well beyond what is needed to maintain a dry crawlspace.

I have two very dry crawlspaces because I maintain exterior drainage and both are covered with a simple plastic vapor barrier and ventilated well.

So I take it you don't have these crawl space systems guys going door to door in your neighborhood trying to sell $10,000 crawl space renovations?

I think we were talking about two different things.

Nathan wrote:So I take it you don't have these crawl space systems guys going door to door in your neighborhood trying to sell $10,000 crawl space renovations?

I think we were talking about two different things.

We're on the same page now. I still don't know what Juan was referring to in his OP.

Juan, what did you mean by "damp-proofing"? On the interior of the crawlspace walls?