Hi Chris, i'm sorry, but i've had to open a new thread for this cos my copper wire phone line & old computer takes ages to load ur thread becos of the pics.
firstly i wonder what profiles were put in for this build & r they still in should be for wall construction?
secondly have u poured the garage floor in with the main slab?
imo the overall profiles should always be to the extemes of the overall width & length. ie runing a builders lines the full length of the house from both outside edges of the garage walls to intersect with a builders line extended from the outside wall of family room to front & back, and a line from the outside wall of bed 1 left & right. measure the diagonal of where these 4 lines intersect.
if this can't be done, or u find the diagonals aren't equal break the house into 3 parts
first part being patio extremes, bed 1 extremes part of family room to width of bed 1 & laundry.
make a square from establishing the exact outside corner of patio, run a bulders line along outside of bathroom wall till it intersects with short external wall of bed 2, a line from exact outside corner of patio along outside corner of bed 1, line from outside wall of bed 1 extended thru till it hits wall between family room & entry. check the diagonal of this area is square.
secondly make a second square by running 4 builders lines to include external walls of bed 2, entry, dining kitchen & bed 3 - this will involve making an extended point outside bed 3 to match width of bed 2. again check diagonal measurements.
third check is for squareness of the family room from the outside extremes of the family room across to a point on outside of bathroom wall and intersection along short external section on bed 2. be careful here, cos i can't till where the line of bed 2 is the same wall line for wall between entry & family room?
basically ur breaking the slab into 3 sections to check diagonals. if u have a fax pm ur number & i'll fax u a copy of what i've tried to outline above.
some one else might have another way of doing it, but i recon this will find if any section is out of square. to me 60 mm is far too much to ignore.
hope this might help - tony