Hello!
I am converting my single garage. The garage floor slab slopes down from the back to the garage door. At the highest point of the garage floor (at the back) it is 100mm below the main house floor level and the overall slope is 100mm over about 6m.
I would be grateful on some advice on the floor build up for the garage conversion?
Initially I thought about trying to level the floor and then having PIR insulation and chipboard deck above. But I don’t know what you’d use to level the floor - anything you’d use would need to be basically 0mm thick at the high end and 100mm thick at the low end to ensure there is enough depth for insulation and flooring above without having a step up into the garage conversion.
So my next thought is timber joists laid perpendicular to the fall on dpm. If I was to do this, you’d start with around 80mm deep at the high end and they’d get deeper as you go along. I assume you’d try fully fill the voids between the joists with insulation so the insulation would get thicker as you go across? My concern would be because of the slope of the floor there would still be air gaps below insulation which is a bit of a concern condensation wise although I would have a VCL over the insulation.
Another option would be to support joists on packers/legs so you would have a suspended floor with a void beneath which would slope to nothing. You could have an air brick where Infilling the existing garage door to ventilate the void but I don’t know if this would be enough as you are meant to have ventilation on 2 opposite sides.
Another more expensive option would be to break out the floor and start again.
I know this is a commonly covered issue but any help would be greatly appreciated! Thanks!
I am converting my single garage. The garage floor slab slopes down from the back to the garage door. At the highest point of the garage floor (at the back) it is 100mm below the main house floor level and the overall slope is 100mm over about 6m.
I would be grateful on some advice on the floor build up for the garage conversion?
Initially I thought about trying to level the floor and then having PIR insulation and chipboard deck above. But I don’t know what you’d use to level the floor - anything you’d use would need to be basically 0mm thick at the high end and 100mm thick at the low end to ensure there is enough depth for insulation and flooring above without having a step up into the garage conversion.
So my next thought is timber joists laid perpendicular to the fall on dpm. If I was to do this, you’d start with around 80mm deep at the high end and they’d get deeper as you go along. I assume you’d try fully fill the voids between the joists with insulation so the insulation would get thicker as you go across? My concern would be because of the slope of the floor there would still be air gaps below insulation which is a bit of a concern condensation wise although I would have a VCL over the insulation.
Another option would be to support joists on packers/legs so you would have a suspended floor with a void beneath which would slope to nothing. You could have an air brick where Infilling the existing garage door to ventilate the void but I don’t know if this would be enough as you are meant to have ventilation on 2 opposite sides.
Another more expensive option would be to break out the floor and start again.
I know this is a commonly covered issue but any help would be greatly appreciated! Thanks!
