Crawl Space Questions (with pics) - DIY Chatroom

burnt03 · 11-02-2009, 10:06 PM

Have a crawl space, accessed through a cold room in the basement. Go down a couple of stairs and the access hatch is to the right, back under the door (if that makes sense). The floor of the cold room is wooden slats over sand.

In the second pic, the drywall was removed because of small patch of mold (might still be able to see a bit on the plastic there). The bottom of the drywall was buried in about 2" of sand and the wood frame seems to be built onto the sfc of the sand (no concrete underneath). Behind that cut portion is more crawlspace.

Third pic shows a heat register off of the main ducting that was covered over and the general condition of the crawl space. Does the presence of the heat register sort of indicate that the space should be heated/cooled (the vents outside are covered up). Concrete foundation walls have white rigid insulation attached.

So, now to the questions!

1) Any suggestions on what I can do with the cold room to be able to sort of seal it from the crawlspace and still use it as a storage room? From what I understand, wood contacting directly with soil is a bad thing and invites pests/rot/etc

2) Should I be uncovering that heat register in the crawl space?

3) The vapor barrier on the floor is not taped together or taped onto the foundation walls. Should it be?

Thanks in advance!!

GBR in WA · 11-02-2009, 10:57 PM

Is there 12" between the ground and the bottom of any beam, as per code?
Or, 18" to the bottom of the floor joists?
Pic. #1 - should be a weatherstripped door with a sealing threshold. Preferably insulated as well. Is the idea of a cold room with slats in the floor for storing your own food, potatoes, carrots, etc.?

Pic. #2-- interior finish should be more than fire-taped drywall, which will mold, if needed as a "cold" room.

Pic. #3--- Yes the vapor barrier should be taped to the concrete wall and foam board added where missing. Also tape the seams of the board. That duct patch is terrible, duct tape as shown has a four year life. (Not counting the cardboard ? patch). I doubt it is for heating the crawl, more like a mistake and ran a duct above instead. (It looks a lot bigger hole than needed?)

The foam board should be blue to stop moisture, not white. http://www.energysavers.gov/your_hom.../mytopic=11620 And it may need to be covered, per code: http://www2.iccsafe.org/cs/committee...E_06_64_07.pdf Because of these characteristics, foams used for construction require a covering as a fire barrier. One half-inch thick (1.27 cm) gypsum wallboard is one of the most common fire barriers. Some building codes, however, do not require an additional fire barrier for certain metal-faced, laminated foam products. Check with your local building code/fire officials and insurers for specific information on what is permitted in your area.
Be safe, Gary

burnt03 · 11-03-2009, 12:23 AM

Thanks for the reply Gary, lots of new stuff to think about!

In answer to your questions...

- I'm not positive on the measurements, but I'm pretty sure they're within the limits (would have to go in again to doublecheck)

- In using the name "cold room", it was more just to put a label on it. It's basically the room that enters into the crawl space, something we'd like to use as additional storage (xmas stuff, etc). What could I use instead of the drywall for wall coverings? Wouldn't it be the same as is I were to put up the 1/2" gypsum over the insulation in the crawl space?

- If I would have taken off that beauty duct patch, there is an actual heat register cover sealed into the side of it. Looking at the picture again, it does look as though they made a mis-cut, but I don't think that's the case (all the other stubs came off the top of the main duct as well)

Am I wrong in thinking that I shouldn't have the wood sitting directly on the ground? Is there another way to insulate the room from the crawlspace or should I just open it up like it looks like it was originally and replace the door with an insulated one?

GBR in WA · 11-03-2009, 11:01 PM

Your local building department would know more as to their interpretation of the code. If the door to that room is not insulated, the warm moist heated air may condense on the warm side. An HVAC guy would know who is familiar with conditioned crawl spaces. You can research this, as much is available on the web: http://www.buildingscience.com/docum...ance-and-codes http://energyvanguard.com/index.php/...ation-solution
What wood is sitting on the ground? Any wood in contact with earth should be treated and rated on the wood to state such. If you remove the patch, the supply air has to return somehow back to the furnace. (and it may be too much volume, cutting off registers down the end of the plenum. This should be part of the complete system designed and figured mathematically by the installer or a qualified HVAC guy.

Be safe, Gary

Ron6519 · 11-04-2009, 08:44 PM

I'd remove the wood sitting on the sand. I'd excavate the sand out of there so a concrete floor could be put down. Then put the wall back in onto a PT plate. Seal the duct with metal tape. There is no need to heat a crawl space. Follow the advice about the vapor barrier and foundation insulation.
Depending on where you live, I would install insulation into the joist bays in the crawl space.
Ron