Weight of tile floor

[Electrician4you]

Originally Posted by kletter1mann

I'm retiling my kitchen floor. It occured to me that the weight of the floor is astounding. The new tiles alone weighted about 900 lbs. The mortar and grout are probably another 400 lbs. And all this is over an existing tile floor laid over a 1 1/2 inch mortar bed. I figure that has to weigh another ton. Seems like a lot of floor loading to me. The joists under the floor span about 12 ft. How close am I to the limit? Should this concern me?

Never tile over existing tile. If tiling on wood floor use hardibacker or wonderboard. Make sure you use the CORRECT fastening screws. Don't be a moron and use the good ol standby ( drywall screws)
Anyone tiling over existing tile should be immediately fired. I don't care if people do it. People do a lot of things wrong.

[James1202]

Originally Posted by eddie1278

You are supposed to have at least 1 1/4" of subfloor for tile. Most homes have existing 3/4 plywood so you need to add another 1/2" to stiffen it up for tile. Also mortar doesn't bond to plywood.

You need to use cement board like Hardibacker or Wonderboard. I prefer to use Hardibacker it's easier to work with.

Unfortunately it sounds like you have to tear everything out and redo it right or else you will have cracked tiles everywhere.

p.s. wait did i read that correct that you installed new tile over old tile?! geez man no no no you are going to have to rip all that out down to the 3/4 ply and do it right. Never tile over tile absolutely not.

eddie1278, you're assuming this is a post-WWII builder's home. Nothing you posted would be expected to pertain to a pre-WWII home or a post-WWII home designed by the owner's architect.