heat crawl space to warm room above

Reply

  #1  
Old 08-05-10, 04:47 AM
Member
Thread Starter
Join Date: Feb 2006
Posts: 7
Upvotes: 0
Received 0 Votes on 0 Posts
heat crawl space to warm room above

my family room has an unheated garage on one wall, the great outdoors on two other walls, an unheated crawlspace underneath and the cieling is the underside of the roof. it's sunken to boot so in the winter it can be a bit chilly when sitting on the couch. i'm considering new floor and the possibility of underfloor heat. i don't want it to be the main source of heat, just a way to make it a bit warmer. the crawlspace is about 3' high and mostly below grade. i thought about insulating the walls and floor of the crawlspace and heating it with the hope that the heat will rise up through the floor and warm the family room a few degrees. anyone heard of anyone trying this? does it make sense? thanks
 
Sponsored Links
  #2  
Old 08-05-10, 05:36 AM
Member
Join Date: Oct 2008
Location: New England
Posts: 10,392
Received 20 Votes on 18 Posts
Heat doesn't like to go down, and being sunken, the cold will collect. Insulation the perimeter of the crawl space with rigid foam board and covering the dirt floow to eliminate any moisture would help.

What type of heating system do you have, hot air or hot water?

Here is what a finished crawl space can look like:
Photograph 5
BSI-009: New Light In Crawlspaces — Building Science Information

Bud
 
  #3  
Old 08-05-10, 10:42 AM
Member
Thread Starter
Join Date: Feb 2006
Posts: 7
Upvotes: 0
Received 0 Votes on 0 Posts
thanks. the crawlspace floor in concrete. would insulating the floor help? heating system is hot air.
 
  #4  
Old 08-05-10, 12:34 PM
Member
Join Date: Oct 2008
Location: New England
Posts: 10,392
Received 20 Votes on 18 Posts
We don't know if they used a vapor barrier when they poured the floor, but just having the concrete helps to reduce the moisture. The primary heat loss is through the exposed concrete and the first foot or two of concrete below that. Heat that is lost to the floor doesn't have a quick escape and essentially builds up a plume of warm soil below, which then acts like insulation.

The rim joist, the wood just above the foundation should be air sealed and insulated as well. Basically seal it to the foundation and any seams. If you are in a termite state, check to see what needs to be accessible.

If you have any moisture/water issues down there, they will need to be corrected, drainage away from the house. But once buttoned up, just add a bit of heat and those floors will improve a lot.

If you had hot water, a zone could have been added between the floor joists. With forced hot air, just add a supplu and return to that space. Check on local codes to see if you would need to cover the rigid foam with sheetrock, it would be heated, but not exactly living space.

If your question was, insulating the floor above the crawl space, insulation will do very little, as there is no heat source. That sunken area will collect the cold like a magnet. Putting a heat source in or under the floor will warm the floor and the room above. There are electric radiant heat installations where you could build a new layer of flooring with the heat built in, and that would then require insulation in the cavities below.

Bud
 
  #5  
Old 08-05-10, 06:04 PM
Member
Join Date: Mar 2009
Location: WA
Posts: 1,167
Upvotes: 0
Received 0 Votes on 0 Posts
It sounds like you have a vented crawl space now, check with your local B.D. before you close it off. If in a very cold area, you could melt the perma-frost and feel your house settle. You need an exhaust for air changes, per code. Depends on the amount of supply ducts below. May need to cover the foam board.
http://www.advancedenergy.org/buildi...l%20Spaces.pdf
http://www2.iccsafe.org/cs/committee...E_06_64_07.pdf
http://www.eere.energy.gov/buildings...s/db/35379.pdf

Be safe, Gary
 
  #6  
Old 08-05-10, 06:37 PM
airman.1994's Avatar
Member
Join Date: Dec 2005
Location: VA
Posts: 5,756
Upvotes: 0
Received 3 Votes on 3 Posts
This can be done! You will need to hepa vacuum the crawl to remove all dirt plus insulate like stated above
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: