SUSPENDED TIMBER FLOOR

Timber joist floors, either ground or intermediate, can be addressed in different ways. A timber floor has no thermal mass and some adapting is required to the structure to enable floor heating to be installed and operate successfully.
The best results are obtained by fixing the pipes between battens and infilling with a sand cement mix, the floor panels are then fixed to the battens. This method can be used either on top of the joists, or by fitting battens between the joists it can be lowered so that the floor panels are still fitted onto the joists with no increase in floor structure height.
Another method is to use profiled metal plates as a means of spreading the heat energy under the floor panels, this method does not impose a weight penalty but the energy output is lower than the batten and screed method.

Suspended Timber Joist Floor
Timber joist floors have no thermal mass, for best results with UFH a small amount (25mm thick) of weak sand and cement can be laid between the battens to surround the UFH pipes. The sand and cement should be up flush with the top of the battens to ensure good contact with the underside of the flooring panels. It is essential that a rigid insulation board (not glass wool) be used to insulate hard up the underside of the plywood (see diagram). Using this method the floor is raised by 34mm higher than it would have normally been and adds approximately 25kg/m² in weight.