hi whitebeam,,okay heres my situation,,im pretty new to tiling,,only done 6 jobs so far,,iv priced a job for a 17 sq metre bathroom refit walls only and ceramic tiles i was told,,customer turned up today with 1000mm by 300mm 12 mm thick tiles..lath n plaster walls in decent nick but not dead straight as requested,,i was going to spend 2moro prepping my walls and makin good all i could before starting,,i do have concerns about the weight of these tiles but thought it would be okay,if lath n plaster is not suitable what other measures could i advise the customer?cheers