Thread: Sealed crawl space

New one on me today, my first sealed crawl space outside of the books.
Had foam insulation sprayed on the bottom of the floor as well as the exterior wall.
No vapor barrier on the ground.
Wet ground in areas due to recent heavy rain and improper exterior drainage.

This was an older home that was renovated down to the studs and sealed at the time of the renovation along with creating a sealed attic.
There were two vents on opposite sides of the house to the outside employing a small fan and a damper supposing one is an inlet and the other exhaust. In my view, this is the first problem since this should now be treated as conditioned space with interior air provided to the crawl.
Also the spray on foam was in direct contact with the ground creating excellent termite cover if not food (do they eat any of this stuff?)

Next question, is there any prohibition against discharging "air to air heat exchanger" air from the attic HVAC into the crawl rather than directly outdoors? Since there is a powered air exchanger, my thought is to provide the exhausted stale but semi-conditioned air into the crawl to provide the required positive air exchange into the crawl without incurring an additional energy penalty .
Am I all wet?

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Originally Posted by Jim Luttrall

No vapor barrier on the ground.

Wet ground in areas due to recent heavy rain and improper exterior drainage.

spray on foam was in direct contact with the ground creating excellent termite cover

Three strikes against buying that mess. You've convinced me, anyway.

Am I all wet?

Wet and dirty from the look of it.

Jim,

I've personallly seen termites tunnel up through that stuff straight to the sill plates. I'd tell a buyer to run like hell if I had inspected that crawlspace.

rick

Rick, not a buyer, this is the home owner that just spent his life savings to renovate the whole house and this was part of it.
Any home that preventive treatment around the perimeter of the grade beam would keep the little buggers at bay?

Originally Posted by Jim Luttrall

Rick, not a buyer, this is the home owner that just spent his life savings to renovate the whole house and this was part of it.
Any home that preventive treatment around the perimeter of the grade beam would keep the little buggers at bay?

Only in dreams. I've never seen a perimeter treatment around a pier and beam actually done correctly that would prevent termites from coming up the foundation walls on the crawlspace side.

Originally Posted by Jim Luttrall

Rick, not a buyer, this is the home owner that just spent his life savings to renovate the whole house and this was part of it.
Any home that preventive treatment around the perimeter of the grade beam would keep the little buggers at bay?

Treat the soil inside and outside the foundation with termidor.

Especially the soil on the inside of the foundation. The only preventive treatment you can do right now in this case.

The little suckers do not detect termidor and when they pass thru the treated soil they pretty much pass in on to one another like a virous and kill off the colony

They can offer up to a ten year warranty as long as they pay the 12% of treatment cost once a year for re inspection cost.

Whoever did the work there Jim had no idea what they were doing.

From the opposing fan and damper assembly to the installation of the foam to the HVAC discharging into the crawl.

Nothing about that is correct or makes any sense.

seems to me like he needs to scrape the foam off the wall, clean all the junk, install 10-20mil plastic. eliminate the hvac vent. seal the fan vents and install a dehumidifier!

A sealed crawl is a great idea but requires perfect attention to detail. The very first detail must be bulk water elimination. Grading, drainage, pumping, whatever it takes.
The next step is to seal the crawl space from the earth with an impermiable barrier. Create a swimming pool type liner.
Third is proper perimeter insulation. Minimum R-10 rigid foam leaving a termite inspection gap at the top.
Fourth is to introduce conditioned air into the crawl space. That's done a number of ways. Some like to pull a slight negative pressure with a foundation fan. Some like to do positive pressure with a small fan pulling house air. Some mistakenly cut a hole in the HVAC supply line. That can be a killer!
My guess is that foam on the ground will ultimately be a failure even with a dry crawl space.
When I inspect one I always finish my report with the admonition to be careful and get educated via a couple of good web sites.

JLMathis

Termidor treatment as Ted said. Full perimeter and in the crawl space. Termidor specifically.