Our Gas dryer has finally moved on and it is time for a new one. The washer is really not far behind and we have decided to replace both. Our laundry is on the 2nd floor of a house built in 1998. I have read a number of conflicting comments about damage to the house from the vibrations from the washer (one even mentioned plaster falling on lower levels). I would like to have some ideas to be able to use front loaders. The manual for the model I am considering states to reinforce "weak wooden floors" I really don't know what that means. I don't currently worry about falling through my floor, does that mean it is not weak? My plans were to screw down 1/4" handi board then thinset 12x12 glazed tiles. Adding more plywood would not be convienient based on existing floor height.