dslreports logo
    All Forums Hot Topics Gallery


how-to block ads

Search Topic:
share rss forum feed


Little Rock, AR

spray can of low pressure filler/ for wall insulation

My house is on a slab and at the bottom of the walls I have air leaks. I took off the baseboard and I can see the wall insulation bat but I have air coming in under it.
Is there a good spray insulation in a can that is not high pressure stuff. I know that great stuff will expand and blow the baseboard off lol
I need to fill this gap and would like expansion without cracking the walls.

I hope that makes since

Scotch Plains, NJ
You would probably want to seal up any air leaks from the outside.


Columbus, OH
reply to sparks
There is such a thing as low-expansion foam. Readily available in big box or hardware stores.

LXI 483
O Fallon, MO
reply to sparks
CRC 14077 Minimal Expanding Foam. It's about $8.

If the gaps are small, no foam product will work. You'll probably want caulk.
If someone refers to herself / himself as a "guru", they probably aren't.

Account deleted

New Jersey

1 recommendation

reply to sparks
I did something like that once. The result is that the cold air was trapped in the wall and the pipes froze. The correct solution was to fix the leakage from the outside.


Pierrefonds, QC
And the final volume is always based on what you initially put in.
So you don't want it to be too big? Draw a thin thin line of great stuff. With some practice you'll get the hang of it.

But ya as others have said, there is low expansion foam from Great Stuff (I think it's the one made for windows and doors).

said by Bob4:

I did something like that once. The result is that the cold air was trapped in the wall and the pipes froze. The correct solution was to fix the leakage from the outside.

I think it's more that the inside of your walls stopped being heated by indoor air leaking in.
The problem was more that pipes were installed in exterior walls without insulation.
But your warning applies to OP.

Shelton, CT
reply to sparks
The bathroom fan exhausts some 80cuft of air every minute.
Unless the leak is major fixing it won't make a significant difference.
If the leak is serious, take out the baseboard, fill with foam, trim the excess and replace the baseboard.

Andover, NJ
reply to sparks
Are you saying the sheetrock does not extend down the wall to the floor, covering the 2x4 that is running horizontally along the slab (AKA "bottom/sole plate")? Is this how you are seeing the insulation?

If you can see that far into the wall, you may be able to seal the sheathing to the bottom sole plate from inside. Remove the baseboard, push the wall insulation up out of the way and insert the tube from a can of great stuff all the way in till it makes contact with the corner of the sheathing and the bottom plate, inject foam as you slide the tube along the sheathing. Repeat for each bay.

It will not take too much foam to make this seal, this stuff expands well.

If on the other hand the air is entering under under the bottom of the sole plate and top of the flooring, a tube of flexible calk is the best solution. Remove the baseboard and apply a bead where the subfloor and sole plate meet.
The difference between genius and stupidity is that genius has its limits.

Smyrna, GA
·AT&T Southeast
reply to nunya
This formula for windows and doors is what you should use so that you don't bow window frames when sealing around them. Proably meets the OP's original question.
Great Stuff Windows and Doors.

But Bob4 See Profile makes an excellent point that you should address this from outside.
nohup rm -fr /&

Moncks Corner, SC
I had a problem like this on a newer home with vinyl siding - the builders left out the foam sheeting that goes between the bottom plate and the concrete slab on one side of the house. Air from outside could actually blow sheet rock dust onto the inside wood floor. The builder took off the bottom course of siding and applied RTV to the gap - that seemed to work.


Decatur, GA
reply to sparks
They now make a version of the spray-in foam insulation that doesn't expand very much so it won't blow off the baseboards.


Little Rock, AR
reply to sparks
I looked at the way its done and you are correct.
their is a 1/2 in square bottom of sheetrock to bottom and the baseboard to the plate.
Its not air blowing in its more of a seeping of air. When it is real cold you get next to it in bare feet and you feel cold. Its a brick home built in the 70's so that will tell you its probably R4 insulation in the walls lol
I am thinking of some type of caulk to fill this area but with 100+ feet of outside wall to do would caulk be the best to fill this or ?


Columbus, OH
There is a material called "backer rod". It is expanded plastic in rod form. The whackers that are made for toys are made from this. It is used for things such as caulking of expansion joints for roads to limit the amount of caulk needed.

Sizes from 1/4" up to several inches. Dirt cheap. If you can't find it easily, try a concrete sawing firm.

It is made from polyethylene, so outgassing should not be a problem. The open cell variety is best for irregular gaps as it will take more compression.