Underside of flooring in crawl

[Bill H]

i recently did an inspection on a home that had been added to, the crawl space under the 4 bedrooms are separated into 2 different crawl spaces including different access panels, there is no water lines or waste/drain lines in the area, all electric runs through attic. my problem is i noticed alot of condensation on the subfloor, i mean water drops. this house is a foreclosed house that has been empty about 9 months, all i can figure is there is no vapor barrier and the vents were all closed. any idea of anything else?

[kurt]

It's not finished.

There should be a vapor barrier (as you know), no vents, insulation around the perimeter, and a heating/cooling source so the crawl is conditioned the same as the habitable space.

There may be any number of other things to consider, but it sounds like your basic POS crawl to me.

[caryseidner]

And don't forget to cover the dirt floor with a vapor barrier and ballast, or concrete.

I was in an unfinished, uninsulated, vented crawl last week. It looked like a greenhouse with all of the condensation that was in there.

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[hausdok]

A 1000 square feet of uncovered soil evaporates about 11 gallons of water into the air every 24 hours. The home is vacant and cold. That moisture has to condense someplace. Get a tight barrier placed. Stake it in place with sod stakes and seal it to the wall and at the perimeter with latex mastic and then either insulate the walls and turn that into conditioned space or insulate the floors and open up the vents.

ONE TEAM - ONE FIGHT!!!

Mike

[RickSab]

Am I missing something? It sounds like an attic crawl in the original post.

[hausdok]

I think he meant to say "under the 4 bedrooms" 'cuz he talks about moisture on the subfloor.

OT - OF!!!

M.

[Erby]

Mike, do you know the source of the "1000 square feet of uncovered soil evaporates about 11 gallons into the air every 24 hours".

I know I've seen it before but couldn't locate it recently while searching for it?

[hausdok]

Jeez Erby!

You must think I'm someone with a memory left. Off the top of my head I cannot. I distinctly recall that when I first got into this business I'd read it was either 7 or 9 gallons and that's what I'd written for a couple of years; then I read something somewhere else that caused me to revise my estimate. I want to say that it was either at Home Energy Mag's website or it was Dr. Joe L's website. If I were to go over to the storage, dig down to that bottom box of files, I might be able to find the reference cited in one of those old files, but I'm not likely to do that tonight.

ONE TEAM - ONE FIGHT!!!

Mike

[hausdok]

Hi Erby

Okay, I think I know where I found it. It must have been in some of the pest control information that I had to read back in 1996 when I was studying for my pest inspector's license here in Washington State. I say that because I just googled "11 gallons of water for every 1,000 square feet of uncovered soil in a crawlspace" and kept ending up on pest management sites.

I found some interesting links: The google tag for the 6th link below specifically states: "A poorly vented crawl can produce over 12 gallons of water per day per 1000 square feet! When your crawl space has been properly vented ..." but I just about wore mmyself out trying to find that in the actual document - it's about 113 pages long. There's a whole pest management education at these 6th and 7th links though!

http://www.engext.ksu.edu/moisture/mf2141.pdf

http://extension.oregonstate.edu/catalo ... ec1437.pdf

http://www.earthcrafthouse.com/document ... 120903.pdf

http://www.state.mn.us/mn/externalDocs/ ... isture.pdf

http://www.houseinvestigations.com/down ... 0pages.pdf

http://www.stephentvedten.com/36_Wood_D ... nsects.pdf

http://www.stephentvedten.com/

ONE TEAM - ONE FIGHT!!!

Mike