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biglurr54 01-13-2012 08:55 AM

Air Barrier in crawl space
I have a serious draft issue in my crawl space. The crawl space is open to an attached heated basement and has pipes for the heaters in the space. It is heated but it is extremely drafty because the walls are dry laid rocks. The floor above the crawl space is old wide pine so the cold air comes through the cracks in the floor and makes the living room freezing. I was going to staple an air barrier to the bottom of the floor joists from the crawl space to stop the drafts this winter. In the spring I will be digging down around the foundation to replace sills and add polystyrene foam to insulate the walls. Will this idea work for the winter with no major issues?

Windows on Wash 01-13-2012 09:14 AM


It may stop the air movement but it will still be cold if there is no insulation.

I would encourage you to move up your insulation plans if you can swing it.

biglurr54 01-13-2012 09:36 AM

The ground is frozen so I won't be digging that out until if freezes. Luckly I have an out door wood boiler so getting heat in the place isn't an issue. But waking up at 2 in the morning every morning to load more wood is starting to get old. I dont want to add insulation because then i run the rick of freezing the pipes. i just want to stop the air movement from the crawl space to the living space. it feels like a fan is on in the living room by any of the cracks in the floor. It is on the top priority in the spring when the ground softens up.

Gary in WA 01-13-2012 09:26 PM

Staple up some housewrap, then when it's affordable later, add insulation and re-staple.


joecaption 01-13-2012 09:48 PM

How does adding R-19 fiberglass insulation up in the floor joist have anything to do with freezing pipes and frozen ground?
Do that and the room will be warm. Put the paper toward the floor, place insulation hangers at least every 24"
What's the plans for that floor inside.

biglurr54 01-14-2012 12:12 AM

If I insulate the floor then the crawl space won't get any h

Bob Mariani 01-15-2012 08:50 AM

The most economical way to deal with crawlspaces is to insulated the rim joists and the walls to R-19. Insulating the floors is not needed. The cold only moves in a few feet from the foundation walls. The delta T (change in temperature) between the living space and the crawlspace is less than 10 degrees. Insulation is used to retard heat flow, not stop it. The floor of the crawspace must be covered with poly either under the concrete rat slab of over a dirt floor. Using tyvek as suggested over the joist is a good idea to stop the air flow into the crawlspace. Another way is to add a small exhaust fan which will depressurize the crawlspace preventing unconditioned air moving via convection into the living space. More on crawlspaces here

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