Monday, April 14, 2014

Crawlspace Challenges

Ok, it's mid-April. We still do not have the construction loan. I don't know how that is possible, but that's the reality.

So we've been working on the house doing whatever we can do. My current focus is air sealing the penetrations in the crawlspace area. This is my job because I like it and I am physically the most flexible in terms of crawling around under the house. In addition I value air sealing more than anyone else involved in this project.

Sealing drain pipes:

Prosoco Joint and Seam Filler around one of the drains. I love this stuff. 

Sealing around duct work:

Air sealing around duct work isn't easy. It's hard to get into some of these spaces. I will foam the really tight areas.
Sometimes I use the Siga Wigluv and sometimes I use the Pro Clima Tescon Vana tape. I primed the Advantech subfloor with a primer first to make the tapes stick better.

Oops! Forgot this one:
Also need to tape the gap in the insulation barrier as well. 

What kind of tape is this? Looks like duck tape.

I think the tape they used to seal the duct joints and to tape the insulation to the ducts is a form of Duck Tape called HVAC duct sealing tape. Regular DUCK tape is notorius for not adhering well over time. All of my ducts are taped with this stuff. I am hoping that the DUCK brand HVAC duct tape is much more adherent that the other duck tape. I am a little skeptical that this will work to keep my ducts from leaking.

The most reliable product for this application is duct mastic which retains flexibility over time and will adhere for many, many years. The reason it is not used as much is because it is seriously messy. The tapes I've used have been field tested in Europe for years and have found to be reliable.

So my crawlspace dilemma is - cut off all the insulation on the ducts and reseal the joints with either mastic or the european tapes or reinforce the tapes on the the exterior of the insulation and hope for the best.

The truth is that I am tired. I've spend quite a number of hours under the house already and I just don't think I can make myself re-tape all the duct joints. In addition, I have already planned to encase the ducts in polyiso foam boxes to nailed and taped to the underside of floor to further insulate them from exterior temperatures. I think that this second layer of reinforcing insulation will ensure that the conditioned air will get to its intended location in the house.

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