Expert: Dan Griffin - 7/20/2010

Question
can you tell me a rule of thumb calculating if I'm putting to much tile in a room?

Answer
ty, I'm not sure what you are asking.

If you are asking about storing or stocking tile in a room:
I would avoid stocking a concenetrated load at mid span.  Most rooms are designed for 40#/SF live load in a uniformly distributed load, so a room 10x10=100SF x 40 = about 4000#.

If you are asking about installing a layer of tile in a room:
AS you look at the figures above, a single layer of tile is virtually inconsequential.  A full 2" thick mortar bed under ceramic in a 10 x 10 room woulld weight about 2500#.  I don't think many people even consider a full mortar bed anymore.

If you are asking about the flexural strength of floor required for tile:
Code requires floor joists to meet L/360 loading.  This means that 16' joist when loaded at its design weight will deflect 16' x 12" = 192"/ 360 = .53333" ( a bit more than 1/2")
Ceramic tile intallation wants stiffer floors than that.  Most require L/480 or even L/600.

This has more to do with cracking mortars, tile, grout lines, etc than with floor collapse.

I hope something here did help answer your question.