Eric,

Thanks for the email! and thanks for the compliment.

You are right on track, install the insulation first on the walls then drape the DrySpace over it attaching it to the foundation wall. Depending where you live you may be subject to a termite inspection gap (3-4"). This means the foam board will need to be held 5" down from the top of the block wall and the Foundation Seal Tape (1.5" wide) goes above that, 5"- 1.5" gives you 3.5" to the top of the foundation.

The other option you have is what is called a flat-lay. The DrySpace goes on the floor and 12" up the wall, sealed and pinned, then the insulation board goes over the DrySpace lip to the top of the wall (minus 3" if required). I only recommend this if you have NO water issues at all, especially from the foundation walls. This will cause water to get on top of the DrySpace and create a new nightmare.

Hope this helps.

Matt Leech
CrawlSpace Concepts
877.379.7658
crawlspaceinfo.com

I wanted to make another comment- The link that Eric shared with me in his email is worth reading if you are unsure about a conditioned crawl space and closing the vents.

Matt,

Thanks for your helpful reply.

As my ideas about the crawl space evolve I'm thinking that putting down a real floor is the best bet, mostly because I can insulate it and make a useful storage area out of it.

I'm thinking about poured concrete with an Insultarp underneath it. In this case, would you put the Dryspace liner on the wall first, run it under the Insultarp, and then pour the concrete?

The other possibility is a wooden frame floor, put down over the Dryspace liner, similar to this project: http://www.komar.org/projects/crawlspace/ -- The wood-based project seems cheaper and reversible if there are problems.

Your thoughts?

Best wishes,
Eric

Eric,

You can use the Insultarp or our DrySpace under the concrete floor, either will do the job.

The wood frame project does look nice when it was finished. Not very many people would have this as an option. I saw this article some time ago, and what I remember most is the guy wearing a bike helmet in the crawl space. It still makes me laugh...


Matt

What adhesive would you use to attach the styrofoam sheet to the concrete crawl space walls. I have read that most adhesives will not adhere long due to moisture in the cement and the styrofoam will come loose. Should I put firring strips on first with a mechanical fastener then glue to them?

Dear Matt,

I see your advice to insulate the walls prior to installing the DrySpace liner. The question that arises is why this insulation needs to be rigid foam boards, and could not be sprayed foam (I'm not asking about sprayed cellulose) insulation?

I note for your comment that the document Eric references at buildingscience.com shows (in figure 11) sprayed foam insulation on the walls, but with the "continuous 6-mil polyethylene ground cover as continuous vapor barrier turned up at the foundation wall", behind the insulation.

I am an aging DIY'er, and had planned to hire a younger person to insulate my crawl space walls and to close off the crawl space vents, with me doing some of the work, as well as providing supervision. As I began to research at this site and others, I am now strongly considering integrating a 20-mil liner into the project, with 12-mil material on the walls and in very low-traffic areas in order to reduce costs. The job would not be minor - this is a 3500 square-foot ranch with a 200+ foot perimeter and a vapor barrier (over the dirt floor) that is no longer continuous, 44 years after construction. Cable TV lines, ethernet cables and house security system wires crisscross the floor - all will have to be attached to the joists about 3 feet above the dirt floor.

Occasional water penetration during cloudbursts in central Illinois gives me pause, but I have done a great deal on the outside of the house to reduce the frequency and severity of the water intrusion, and also have installed a working sump pump in the crawl space.

Thank you for a very helpful website, and a business that blends well with the efforts of homeowners to tackle projects with their "sweat equity" - although that, too, could raise RH :)

Dave
Champaign, IL

Rich,

Thanks for the comment!

There is a glue that works well in the crawl space and it is make by Loctite. We just added it to our products, but it is not on the site yet. If you would like to buy it just give us a call at the office 877.379.7658. I believe it is $5.90 a tube but don't quote me, Jo will know the real price.

Dave,

Thanks for the comment!

Well there is quite a bit of buzz about using spray foam in a crawl space. I personally don't think it is the right product for under the home due to the inconsistent application and misleading sales practices of the companies that sell this product. It limits home maintenance and stalls if not stops the sale of a home if installed improperly. Of course if those were not issues then I would say the only place it should be used is on a stone foundation or possibly on a block foundation if installed properly. The spray foam is more expensive and the DIY kits mostly do not cover the stated square foot. To me there is a better product for insulating the foundation, rigid. I know the thought of spraying something on the wall sounds easier but that does not make it better.

Let me know if you have any other questions,

Matt

thanx for posting, love it as hell