u value cavity wall.
Posted: Sat Sep 29, 2007 7:49 pm
Lifted ground floor roof and built on top.Existing cavity walls 265mm now need to achieve u value of 0.3(up to 300mm cavity now) .Building inspector has suggested using Gyproc Thermaline plus (this is 35mm thick with plasterboard)only trouble is @£30 a sheet its expensive :cry: . I need at least 10 sheets!does anyone know of an alternative :idea: peferbly cheaper :?: would be using 12.5mm board on walls.