Insulating a concrete slab under 1/2 living room

9 years ago

I don't know where to post this, however Ill start here.
I have discussed this a couple years ago without doing anything. I have a house with a 20 x 32 living room. 10 x 32 is a wood floor with crawl space, the other 1/2 was a porch and has a 4" concrete floor held up with 4 sided 4" block walls, The crawl space under the house is much warmer than under the cement portion which is an enclose room with one opening and one 32 ft wall which is the outside wall 4" block with brick on the outside. There are 32 double 8" block columns holding it up. The ground is dirt covered with plastic. Inside the house there is ceramic tile covered by laminate with pad over it. Its about 5-10 degrees colder than the rest of the house. A friend just put 1/2" pink foam board R3 around his crawl space and said it increased the warmth of his floors greatly. I wondering what to do to warm the above floor or the concrete portion. I could put pink foam on the outside wall, and/or glue it to the bottom of the floor although its covered with roofing paper (tar) and glue may not hold the board up. I'm thinking that all those columns are conducting a lot of cold up to the top and don't know if it would be better to cover the underside or just the outside wall or both. Would it be worth the cost to use 2" instead of 1/2"?
Any ideas?

This post was edited by larrylwill on Mon, Nov 17, 14 at 0:34

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Comments (2)

klem1
9 years ago
It does sound like there might be a problem with the concrete portion of the room but we would also like to know as much detail as possible on how hvac is laid out. I hate chasing rabbits all over then be told one was hidden beneat a bucket from the start. It appears you arn't looking to jump right on this so I'll only get you started with seeing what can be done and how much effect it will have. The nuts and bolts of remediation can come later,depending how much your enthusiasm wanes after stareing down the barrels of realality.
Use quick reading digital thermometer to read A outdoor ambent, B air temp in inclosed space beneath floor C soil temp beneath floor at 2" 6" and 12" below grade (test near center of room and midways between columns,not next to columns nor block walls.) Repeat soil test within 2 inches of 2 or 3 columns near center of room and 2 or 3 locations 2 inches from inside of block wall. Record and average readings for each test set. You can't use a pos device nor curupt readings with breath,body heat,lights and such. The differentials can be much smaller than you are acustomed to in daily life but are meaningful non the less. Try doing this after 3 or more days ( longer the better) of fairly consistant sun.wind,precipt and temps ( day night flux is inevetable as long as there isn't changing weather patterns.) A good thermometer isn't expensive and can be used for many different things for years to come. I try to keep secret the device I used for steak last yesterday was used last week on a boiler system. After you assemble and chart your data, you should have an aah haa moment.
larrylwill
Original Author
9 years ago
Since I have a Flir I can do better than a quick thermometer. I can also check the temp of the walls bottom of the floor and columns. The reason I don't seem in a hurry is this has been going on since we bought in 2007, every winter I think I'm going to fix it but then it get warm outside and I forget about it. Today its 26 out right now at noon. It might be a good day to take those temps. Just checked the inside floor 75 on the insulated part and 68 on the slab part. Heat pump set to 75.

This post was edited by larrylwill on Tue, Nov 18, 14 at 21:13
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