Timber joist - Internal Floor Minimum 100mm Rockwool Flexi is to be fitted between the joists supported by the ceiling. The flexible long edge of the slab allows for the 600 mm wide product to be flexed into the space between timber joists.
Where joists are spaced at 400 mm centres, 1200 mm x 400 mm wide Rockwool Flexi should be used. All material joints must be tightly butted and lay over 12.5mm plasterboard ceiling with a minimum mass of 8.5kg/m2. 18mm t & g chipboard is to be laid on top of the joists as a base floor for the finish floor cover e.g. Carpet.
SoundPro solution To meet Part E2 Rw 40dB Test Report ref. L03 264 & 265 Rockwool SoundPro guidance specification . Standard 18mm t&g flooring grade chipboard, mass per unit area 12.4 Kg/m2 . Timber joists @ 400mm ctrs. . 100mm thick Rockwool Flexi between joists . Single layer of Standard 12.5mm plasterboard ceiling, mass per unit area 8Kg/m2
Fire protection One hour fire resisting floor.
Install a continuous run of 25mmų chicken wire mesh across the whole floor.
Form the mesh so that it follows the profile of the joists and the top face of the ceiling lining. 100 mm Rockwool Flexi to fit tightly between the joists and supported by the mesh. Lay new floor of either (a) 18 mm flooring grade t & g chipboard or (b) square edged softwood boards plus a layer of 3 mm hardboard above or below the boards.
