Garage conversions

[splott parker]

Don’t forget to check finished floor level to u/s of existing joists. You’re going to need insulation on the existing concrete floor, 100mm at least (although some authorities regs are now 150mm, ridiculous depth really), u/f heating snake clipped to the insulation. 50mm sand/cement screed or liquid screed over the lot. That’s at least 150mm higher than your existing slab. I presume you’ve got bare joists at the moment so insulation (100mm at least) should be fitted between them, this would create a ‘cold’ roof. Given that it’s a flat roof and not pitched you can’t get above the joists to insulate over the top so you should really be using an insulated plasterboard on the ceiling to complete uninterrupted ceiling insulation, this would most probably result in your ceiling finish being 50mm below u/s of existing joists. Doing it this way, which is normal practice now, would result in your storey height being 200mm (8 inches)less than it is now.

[splott parker]

Just got to add as well that many garage slabs are laid with a gradient which is a bugger, if you don’t want to take it up you have to use the highest point as your sub floor datum which could result in even less head room. Windows are often a pain as well, normal, non kitchen or bathroom, cill heights are 900mm with a 1200mm window given you the conventional 2100 head, u/s of lintel, high, sometimes hard to achieve in an existing garage. Bit of planning before striking a blow is required.