need to get access to a roof space above an extension, the only way to get to it is via the loft hatch then through a very small hole in the wall through to the new extension. not sure who they got to wire up the electrics but they must of been bloody thin. Im wanting to know how much of the internal wall i can open up, it is thermalite block through to a brick wall. the hole now is about 15 x 15 inch roughly (to small for me anyway, and im not exactly a big fella.