Suspended timber floor construction

Hi, I am new to the forum and just planning out my new build timber framed studio in my garden. I will be posting further details soon by my initial concern is my proposed floor construction. I live in East Lothian Scotland. The village where i live is peppered with shallow mine workings which are un -recorded. The local council insist on taking precautions when building regardless of what or were you are building as none of these mines are recorded. This usually means heavy foundations regardless of the size of building. I am planning to build the SAE Garage studio 2 plan. I will be recording drums in the live room and other instruments will be di`d from the control room. I do not mix at very high volumes. My drummer is very loud !! Closest neighbours are 11 metres away over the street. My proposed solution for the floor would be a timber joisted floor supported of perimeter edge beams which in turn would be built of masonry piers built of six pad founds. This would keep the concrete / excavations to a minimum. I am concerned that by using a timber floor there will not be enough mass to stop sound (LF) form going through the floor. I was curious if filling the void between the joists with sand would help the mass of the floor. (or and alternative to sand !) This detail is common in the old Edinburgh tenemants where separating floors were filled with ash deafening. I Would appreciate some initial advice regarding the feasibilty of the timber floor for this purpose or if i am asking for trouble by using this method then its back to the drawing board !! I attach a draft detail of the proposed wall / floor construction. I look forward to your advice. Regards CF.

what is the upper floor actually sitting on? are the sleepers sitting on the floor joists or is there some sort of rubber isolation pads?

Hi Glenn, I was thinking of using Proctor Dynamic batten which is readily available from builders merchants locally. Its used in timber frame apartment construction here and is a timber batten with a bonded resiliant strip which would sit on top of the structural deck of chipboard / plywood which would in turn be fixed to the main joists. http://www.proctorgroup.com/index.asp?lm=13 CF

looks nice. according to their spec, a respectable 30db below 125hz on platform floor.