insulating the exterior foundation
schlich
| Posted in Energy, Heating & Insulation on
i am digging out my basement not because i want to but have too and i am insulating the foundation with rigid foam i am having problems finding material to cover the foam that’s above ground level that looks nice. i thought about using stucco but i will not stand up to a weed eater got any ideas
i live in montana so it has to stand up to cold -40 cold
Replies
First Law of thermodynamics, or heat transfer.
The First Law of Thermodynamics is a version of the Law of Conservation of Energy which shows that heat always moves to cold.
Insulating the outside of a cold space is a waste of time and money.
You will acheive more by insulating your floor, if you want to keep your heat out of your basement.
Laying sheets of closed cell insulation, like polystyrene, blueboard etc over your current floor and then covering that with a new fully floating floor, will stop heat loss through the floor. To make the best of the new floor, make sure it does not touch any other part of your home, that will cause your heat to conduct out of the floor into say, the frame or base boards.
"Insulating the outside of a
"Insulating the outside of a cold space is a waste of time and money."
And what does that (bogus) claim have to do with the laws of thermodynamics? Explain it to me.
Yes, the floor should be insulated too (and I'm sure the OP is covering that aspect), but, on a square-foot basis, wall insulation is more effective since the walls are exposed to more extreme temperatures.
And whether insulation is on the inside or the outside of a wall makes little difference. Nor would allowing a "floating" floor to touch the walls substantially (if at all) reduce insulation effectiveness.
Heat - understanding it.
You really don't understand?
When you heat a solid object, like a wall, the heat spreads in all directions, through, down and up, etc. Placing the insulation on the warm side, slows the movement of heat into the wall and keeps the room warmer, fix 10 inch thick closed cell insulation to the inside of the wall and you stop all measurable heat from entering the wall. On the other hand, placing the insulation on the cold outside of the wall, means the heat from the room is absorbed by the wall, is spread throughout the wall and passes into the ground and the frame, being lost in many other directions, some heat will not pass through the wall into the cold air, it will simply get lost in other directions. Put simply, if you want to save the most heat/money, insulate on the room side of a wall.
If insulation needed to be perfectly uniform across the entire structure there would be no point in insulating any house, as there is no way to effectively insulatate windows.
Foam on the outside is relatively cheap and easy to install and reliable, and (as in the OP's case) often fits well with waterproofing schemes, etc. Whereas insulation on the inside is often hit-and miss and takes away interior space..
Insulating the outside of a basement wall may not be the waste of money you think. If the basement is heated, it's not a waste. If the heated space is above the basement, insulating the walls may be better than insulating the floor. Insulating the floor results in the basement being very cold ... increasing heat loss through the floor. Insulating the wall keeps the basement at a higher temp (since the ground temp is around 55 degF) and the heat loss to that is much lower. In cold climates, I'd rather connect my house to the [relatively warm] ground temp than the -20 OA temp. Maybe in addition you insulate the floor, but insulating the walls isn't the slam dunk 'waste of time and money' you think it is.
There are lots of other things to consider the original poster didn't mention ... like is the basement finished/occupied? Is it dry or is it dirt? He may not have the option of putting in a couple inches of insulation on top of the floor and floating a floor above that. Assuming he can is a leap of faith.
Avoid weedeating, landscape differently?
We've found 16 oz. copper to be far more satisfactory than stucco, several choices for appearance. However, the automotive clear coat I used to arrest patina development would not be a good choice with your weedeater. Eye of the beholder about "looks nice". No weedeater lives here so I don't know how copper would stand up, but easy enough to test.
I used colored flashing metal. I had it bent to fit the profile I needed ... in my case up the insulation, 45 to the wall and up vertical under the siding. You can get a variety of colors. Your local sheet metal guy can give you the profile you want.
As a side note, it's not good to have e.g. grass/lawn up against the house. Provide some kind of planting area/no grass area against the house. If you finished it with e.g. stucco, sprinkler overspray will destroy the stucco over time. It will destroy lots of finishes over time ... including concrete and masonry.
here is more info
ok i hope this helps answer some of the questions first off i am digging a basement on my house due to a cracked foundation and the cost of fixing the foundation was just as much as putting in a basement .
the walls i am putting in are cinderblock with the cores filled with concrete. 2" foam not only is the foam being used as insulation but as water break because all i can get here for foundation waterproofing is roofing tar. the ground is always moist its decomposed granite and sand.
when i get ready to do the floor it getting a radon system a sump pump and a layer of foam.
If you actively use the basement for anything (actively heated or not), installing insulation is a reasonable thing to do. In the case of the poster, there is minimal labor cost in doing so. If there is any future chance of full basement use, insulation is a very reasonable idea.
As another mentioned, sheet metal is a good choice. I used it on my shop which has exterior foam on the buried concrete foundation. Also mentioned is to keep grass back away. This will prove to be a good choice over the long term.
Are you installing a foundation drain system? You should.