Hello there, I bave a problem with some big gaps at the bottom of some existing plaster board. Think of a loft with boards on the floor and as the plaster comes down to meet the floor it's been left open. All the gaps are about 45 inches long and 3 or 4 inches wide apart from one which is the same length but about 7 or 8 inches wide in some places. The guy wants plaster board in there but I have nothing to attach it to. It's pretty much just an awkward hole that the fella wants bodging unfortunately. Any ideas?? Thanks