How to insulate garage floors
In most cases, the garage floor will be a solid concrete slab. To insulate this, you may need to create a step-up from other internal spaces (assuming the existing floor height is the same as those in the rest of the house). If you choose to retain the slab then a damp proof membrane should first be laid. The only alternative is to dig the slab out which can be fairly costly and time consuming.
The installation process is then fairly straight forward. Eco-Versal
boards should be cut to size and loose laid with 20 mm upstands around the perimeter. A separation layer is then placed above this followed by the floor screed.