Floor guide

Floor insulation thickness guide

Floor insulation thickness depends on the floor type, the target U-value, and the resistance already provided by the slab or structure.

Floor type

Ground floors, suspended floors, and slab-on-grade floors do not all behave the same way.

The target U-value determines how much resistance the insulation has to supply.

Combine the target with the existing resistance and lambda to estimate thickness.

Open the calculator for a custom floor build-up.

See a floor-specific target-U example.

Read the broader thickness planning guide.