Floor construction query

[padstar]

I have installed a new suspended floor in our extension and it has worked a treat 8x2's with a large air gap underneath to keep things dry.

I have hit a stumbling block in the new utility room. This was originally a garage. I had the original slab broken out and installed a vapour membrane 100mm insulation and 100mm slab. I then decided to use a bit of the garage to form a utility room. The slab sits 6" below the top of the joists. As this is an insulated slab below with damp membrane can I sit 4x2's flat as bearers to give some air flow and then 4x2's on top foowed by the deck? Building Control will not see this and I know its not perfect but given it is a small room would it work.

The room is 1800 wide so if I sat 3 bearers down the max span of the 4x2 would be 900.

 

[noseall]

I have installed a new suspended floor in our extension and it has worked a treat 8x2's with a large air gap underneath to keep things dry.

I have hit a stumbling block in the new utility room. This was originally a garage. I had the original slab broken out and installed a vapour membrane 100mm insulation and 100mm slab. I then decided to use a bit of the garage to form a utility room. The slab sits 6" below the top of the joists. As this is an insulated slab below with damp membrane can I sit 4x2's flat as bearers to give some air flow and then 4x2's on top foowed by the deck? Building Control will not see this and I know its not perfect but given it is a small room would it work.

The room is 1800 wide so if I sat 3 bearers down the max span of the 4x2 would be 900.

I'd be tempted to plonk 75mm insulation down and screed the rest. Or do you need airflow to vent the other floor?

 

[catlad]

4x2 will be plenty strength wise.

 

[Andydevon]

If it a utility be mindful of washing machines on high spin cycles. If you know where they are to be located then concrete there and bearer for the rest.

 

[padstar]

If it a utility be mindful of washing machines on high spin cycles. If you know where they are to be located then concrete there and bearer for the rest.

As in raise the level with concrete in that location and sit the 4x2 straight on the slab rather than a bearer? If I fixed the bearers to the slab would thay not suffice?