I really find this difficult to believe, if true it will have looked awful even before anyone fell through it, plasterboard sheets are 48" wide and usually fixed to studs at 16" centres, with just studs round the circumference they would have moved all over the place when they were skimmed and would literally move in and out as you closed the door. 4" x 2" is certainly the usual standard, not really sure that 6" would acheive much apart from using more wood.I would advise anyone thinking of building with a timber frame, NOT to look at the huge building sites, using this method, a proper timber framed house, which I hope we are talking about, everything is more solid, 6x2 inch timbers, not the 4x2 used en masse, how long they will last ? A friend, who helped a removal firm, at times, help a move to a flat in London, while manoevering the 3 piece in, he tripped, and went straight through the wall, into next door flat, the dividing wall, consisted of a sheet of plasterboard each side, with a 3x2 surround, no insulation, no 'crossing' timbers just a single length of 3x2, between each sheet, and for those that doubt, I have seen the photo's.