I have a problem with air leakage under the base boards of our new home. I know there will be some temperature difference but how about an 8° to 10° difference? It seems to be all throughout the home. The home is built on a slab.
I have pulled back the carpet in areas and one concern I had was it looked as if the sill plate was bowed and not tight to the slab. I could stick a pocket knife blade between the sill plate and the concrete. The contractor has done a blower test on the house and assures me that we are at the standard for air leakage.
One of the closets can be as low as 49° to 55° on a cold day. This is not normal. At one point they pulled the carpet back in this problem area and you could see daylight from the garage under the base board. They applied caulk in one corner of the closet but still there is a big temperature difference. Any suggestions would be great!
Best Answer
If the concrete slab is not perfect, and none are, there is always the possibility that there may be a space between the bottom of the lower plate and the slab surface. In the case of a poorly prepared slab this could be more prominent.
Back in the day that I helped build houses we would unroll a narrow strip (about the same width as the lower plate) of this pink colored foam material. The closed cell material was about 1/4 inch thick and would fill the gaps between the lower plate and the concrete slab. It was compressible so that in areas where the plate was a good fit and/or securely fastened to the slab via the anchor bolt it would be squeezed tight.