Creating timber frame floating floor

[Markyboy1972]

Guys,

I'm looking to add a timber frame floor to my integral garage to eliminate the step down from house, through internal door, into garage. The difference in level is approx. 90mm. The current garage floor concrete slab is surrounded by breeze block walls.

I intend to put a dpm onto the slab then create a timber frame with joists at 400mm centres. Frame will sit on floor with some attachment to the breeze block wall. I'll then add insulation and 18mm chipboard which will be screwed.

Am I missing anything and does this all sound good? Do I need an additional Dpm on top of joists before adding chipboard?

Any help appreciated as I'm not convinced about the strength of the combi insulation glued to back of chipboard that you can buy.

Many thanks
Mark

[Dbear]

I'm assuming you want to convert it to a room, otherwise the drop in levels is for a reason.
Don't connect the floor to the wall, the sound transmission from wall-floor and visa versa may drive you mad.
Use a decent dpm under the joists (treated), use some sort of expansion material where the joists touch walls, and between the wall and flooring. Personally i'd use seperate insulation, maybe double it up due to it being a garage conversion.
Does this help ?
Or did you do the job back in Nov (O:

[Dbear]

I'll just reiterate...... It's not a floating floor if you have fixings to the wall or floor.

[andy01]

to comply with robust details, the 90mm void is not big enough to comply with regs. you will need air bricks to ventilate the void. however there are lots of ways to solve problems so maybe this is ok

i think changing the use of a garge requires planning permission due to loss of parking space

i think it also requires building regs as now a habitable space hence needs proper ventilation and insultion etc