Concrete/Joists , Joists/Concrete

[midgeybin]

Undecided as to best course of action in building studio floors.Which gives the best low end isolation.I suspect A ,but by how much.
A 6 inch reinforced slab on 6x2 joists on pucks.Rockwool to joists
B 6 inch reinforced slab on sub soil with 6x2 joists above on pucks supporting floating timber floor

[rod gervais]

Undecided as to best course of action in building studio floors.Which gives the best low end isolation.I suspect A ,but by how much.
A 6 inch reinforced slab on 6x2 joists on pucks.Rockwool to joists
B 6 inch reinforced slab on sub soil with 6x2 joists above on pucks supporting floating timber floor

You forgot "C"

C 5" slab on grade with isolation joints.

If you have the option of isolation the slab - why would you want to bother with wood at all?

Rod

[midgeybin]

Thanks for the reply Rod.Just got planning permission for Studios in City centre. Its in a basement with 15 foot ceiling hieght. My initial planning application was for a 6 inch slab floating on a resilient layer ,Rockwool or similar,with timber stud walls built on the slab,and ceiling joists on the walls.As attachment.However I have been reading Knightflys posts and he seems to favour an air gap below the slab ie joists on pucks with Rockwool infill to control low end kick drum etc.I have 6 rooms planned in all each on its own seperate floor.Rooms are 2 feet apart.So flanking through the ground into adjoining rooms is a concern.I have concerns though with floating a concrete slab on joists, it would be very difficult to calculate puck spacings and thickness given the extra weight of the walls and ceiling. One option I am considering is to pour the 6 inch slab and build walls as per usual then pour a 4 inch granolithic layer on top of the concrete with resilient layer between.The quality of the drawing is not great but it gives some idea of my propsed construction. So my query is should I go for joists to float the slab or continuous resilient layer.

[knightfly]

Is the MAIN slab ((1) in your pic) already there, or is that to be poured as well? Steve

[midgeybin]

Hi Knightfly.The Grey slabs in the pic are new 6 inch pours.A new slab for each room.The brown area along the bottom is existing subsoil.