I own a 1940's pier and beam house and am trying to tile in one bathroom and the kitchen. My brother's decorator and tile guy say, "All gotta go and put cement board back in". Is this REALLY necessary or is this just 2000's America goverened by lawyers and accountants talking??? Did cement board even exist in the 40's and 50's??? Didnt these old houses have tile "successfully" back then also? Okay - so a grout line cracks 5 years from now - Is repairing that when it happens cheaper than me basically dismantling my entire house now????