Insulation in floor

Ivor the Engine

When I had a new floor laid in my basement I had 100mm of Celotex put in, which I thought improved the general heat loss and kept the floor warmer.

Had a builder look at the kitchen last night, which has a thin concrete pad on top of soil.  I suggested digging out and doing much the same thing I'd had done in the basement, but he tells me this would not improve the ambient temperature of the floor, nor protect from heat loss as the earth has a constant temperature.

Is this true?

Trollslayer

The ground temperature doesn't vary much but it is colder than you want for a room so youwould gain a bit but I don't know if it is worth the bother.
He has a point that it varies an awful lot less than the air temperature, hence well buried pipes are extremely unlikely to freeze.

IronGiant

Probably "not worth it" rather than "won't do anything." We laid vinyl tiles and a nylon fibre underlay backed carpet on a cold garage floor and it's just as warm as any other floor in the house.  Can you upgrade the flooring if it feels cold underfoot?

Ivor the Engine

​Its going to be a galley kitchen so two thirds of the floor would not be stood on.  We'll also have a fan blowing warm air across the floor, plus no gaps, so I'm thinking that it'll probably be OK.

Just a bit disappointed that my 'bolt and braces' approach looks needless.