Hi everyone first post ,but great web site .I am just after slabbing my concrete selfbuild and was considering puting insulated plasterboard on the inside of the external walls ,there is kingspan in the cavity already is there much benifit in doing this anyone out there have it done any tips on putting on these slabs i heard about ones that are glued on to walls are these good, or are the plastic mushrooms better,considering doing main kitchen/living area 5 windows in this room 1 is 12ft high and patio door will all heat just go out windows (all double glazed low e ptc),sitting room ,main bedroom ,thanks in advance..