Loft boarded out over full-depth insulation

A raised loft deck with the legs screwed down onto the joist tops, so the insulation underneath stays at full depth.

Loft boarded out over full-depth insulation

The legs are screwed down onto the top face of the ceiling joists, with the mineral wool left lying uncompressed in the bays between them. Nothing bears on the insulation at any point.


Boarding straight onto the joists is quicker, and it is what most people find when they look in their loft. It also crushes the wool flat and costs you the insulation performance you paid for.


The hatch was cut in and trimmed, and the deck runs the length of the roof space with the boards staggered and screwed down.