I’m having part of my basement slab poured next week. A couple of details that I’m undecided / unclear on.
1. Architect specified rigid foam insulation under the slab 2′ wide all the way around the perimeter. What is this for? Why not the whole floor?
2. I live in NC. Do I have to worry about termites getting up into the foam? Can I get foam that has termite protection in it or is it something I get sprayed before the pour?
MERC
Replies
The ground outside will be cold in the Winter. I am assuming that the space above the slab (and the slab) will be warm in the Winter. The idea behind only 2 feet of foam is that by that distance, the warmth from the inside will have warmed the ground beneath the slab to "fight back" the cold.
Does that make any sense at all? Someone else will explain this better, I am sure.
No clue on the termites
My basement floor is around 6-7' below grade. I wonder just how cold gets that far down. I can't imagine it gets that cold. On the other hand I did pour an ICF wall so I guess I shouldn't bail out now on the insulation.
MERC
Keep in mind that I am just passing on what I was told in a seminar held for a home builders association about 10 years ago.
The insulation around the perimeter... 2' in... will provide maximum return on the investment.
That was their words, not mine. I would be interested in the level of comfort that might be realized with its intallation though.
As a builder I do feel it is my job to provide the best value per dollar to my clients. I can sell a customer a patio door that has an upcharge on the type of glass that is in it that can top $200 . They would never see the results of that investment on a savings in heating cost, but they will notice a difference in comfort level when the temperaturers are at their extreems (both hot and cold). I think this applies to your basement floor situation as well.
Scott T.
>> I would be interested in the level of comfort that might be realized ...
Good point. Presumably comfort is one of the reasons we're willing to pay money to insulate and heat our homes. We could save a lot of money if we just set the thermostat at 40F to keep the pipes from freezing.