Everyone says you need to insulate the foundation. Is it really so?
More than once I came across in construction forums, and here, in the comments, two diametrically opposite opinions regarding the need to additionally insulate the foundation. Some believe that this investment will never pay off. Others believe that insulating the foundation and blind area increases the temperature in the house. I will give my comment on the topic.
Let's start with science. Here is a thermal imaging survey of a strip foundation, which is buried below the level of soil freezing, which is correct, but not always found.
At -10.9 ° С outside the temperature of the "tape" ranges from +2.5 to + 5 ° С. The temperature difference δT reaches 16 degrees between the foundation and the street, and between the house and the street - 30.9 degrees (+ 20 ° C is maintained in the house). Conclusion: as you can see for yourself, the foundation gives off a lot of heat even with a relatively small temperature difference.
Thermal insulation with a 100-mm layer of extruded polystyrene foam (EPS) will more than solve this problem. If in winter the air temperature in your region rarely drops below -20 ° C, such a thickness of insulation is "for your eyes".
And now a subjective observation. An increase in the temperature of the subfloor from the standard + 7 ° C to 14 ° C excludes the so-called "cold leak" to the first floor. Anyone who lives in a house with wooden floors will understand perfectly what I mean.
To achieve such a temperature in the underground, it is not enough just to insulate the basement with foam, here you will need the construction of a simple heat accumulator. How to do it?
You will need sand, the same foam layer and concrete mix.
If possible, pipes can be built into the battery, so the battery keeps heat for 1-1.5 months of winter.
The details of creating a heat storage device are described in the video: