How do can I insulate an existing basement floor from 1906?
Old house; basement is only 21% of total under house footage. 79% is crawl space. Basement Never painted. Walls go up 4 ft to a 2ft wide ledge and then the old stone foundation. 1 side is an exterior wall; 3 sides are crawl space beyond the stone.
A lot of heat is lost through uninsulated basement floors, so good idea to fix that. We can help, but a couple of questions first – what is your climate zone, and how much head room do you have? Both those answers would determine how much insulation is best and how much you have room for. But in general, here is a good page to start on –
How much insulation does a basement need?
As for carrying out the work, is there a history of flooding? It would be smart to install a sump pump to avoid basement water damage before you install a new floor.
And as for best technique, see this page here –
Preventing mold when you insulate your basement
Once you’ve laid insulation down, you can lay a wooden ‘sleepers’ and a subfloor, then finished flooring on top, or you can pour a self levelling concrete. If those pages don't answer all your questions feel free to drop us a few more details, includucing whether or not it will be used as living space and we can probably help more.
This is in Springfield, MO. Climate zone 4. Basement head space is 6 ft to bottom of joists. There is a sump hole and pump. No obvious past flood stains.
Your winters aren't too harsh in general, and that 6 feet of head room is right on the cusp of whether or not it can be usable and if you can walk around upright. You could really benefit from at least 2 inches of insulation on the floor, but I don't think I'd go more than 4 inches, so it's really down to head room and how often you want to go there.