I'd like to insulate my (concrete) garage floor. It's single skinned so I will seal the concrete (1st coat sealant, 2nd coat sealant + SBR). I will then use tanking slurry on the walls (1st coat slurry + SBR, 2nd coat just slurry). I expect a little slurry left over so I will use that to re-coat the floor (3rd coat). I expect that would take care of any moisture coming in. I then want to insulate the floor, but what are my options, assuming it's even worth it? This is the floor plan: My garage is 3.14m x 5.95m so I believe my PA ratio (permiter / area, or ((3.140+5.953)*2)/(3.140*5.953), is 0.97. That means to get a U value of 0.22 I will need 100mm of insulation. I have 250mm from concrete to door level. I can probably push it to 300mm (that being the final floor level). Firstly, is it even worth it? I plan to live here for the next 20+ years and I just want the floor to not be freezing in the winter. I will insulate the walls and roof, and have a heat source in the garage. Should I even bother with the building-regulation level of insulation? Secondly, if it's worth insulating it, what are my options? I believe I need insulation then some sort of structural board on top (I'm leaning towards plasterboard to keep it thin), and cover it with vinyl or some-such material. Any ideas and recommendations welcome.