Upgrading existing timber floor for one hour fire resistance
Remove floor boards and install a continuous run of 25mmø 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 19 mm flooring grade t & g chipboard or square edged softwood boards plus a layer of 3 mm hardboard above or below the boards.

Tested solution to meet thermal, acoustic and fire regulations.