Insulate an existing slab?

[timgr]

Pretty sure the answer is no ... and I can't imagine any easy way to do it.

However, is there any way to keep from losing as much heat through the concrete floor of my garage, now sitting on bare earth?

 

[5wndwcpe]

From all that I have heard, you lose most of your heat outward rather than downward. In other words, sideways through the block, as opposed to down through the slab. You could excavate around the foundation and insulate it from the outside, but I'm not sure if you would realize a large enough gain to warrant the time and expense.

 

[Steve in Mi]

Pretty sure the answer is no ... and I can't imagine any easy way to do it.

However, is there any way to keep from losing as much heat through the concrete floor of my garage, now sitting on bare earth?

Yes there are ways to insulate an existing slab. None as low cost as initially insulating but it can be done. One method is to skirt the perimeter of the slab with rigid foam and protective outer jacket to some point near grade, then, angle downward and out away from the slab enough so as not to disturb the ground compaction under the slab itself and provide a shelf of rigid foam. Once you are sufficiently away (again to avoid disturbing ground compaction) trench down to a depth equal to the local frost depth to install a vertical perimeter wall of rigid foam about the slab.

Your intensions for use/heating, the other insulation in the total insulation system and soil condition will all play a role in costs and decision making. Sometimes, for a given owner, personal comfort (warm floor) will be weighted more than a particular payback period.

Another method perhaps worth consideration in raising the building a block or so high, applying poly and rigid foam on the present floor and about the perimeter then pouring a new floor on top.

 

[timgr]

Thanks for the suggestions, but I don't think either excavation or elevation are practical in this case. The floor is already about a foot above grade, and the building is sitting near or on ledge. I doubt very much I could excavate enough around the building to make a difference.

I'll get some rubber mats to stand on if my feet get too cold.