My floor tile/grout is cracking?
Welcome back Donnie here with Donnie D’s Tile & Remodeling LLC in spotswood New Jersey,
I get sooooo many of these calls for failed tile installs in spotswood New Jersey, most of the time they are on floors. Now your hear cause you want to know why the grout is cracking. The tile is moving and maybe making a crunching noise. Well to keep it simple the tile is moving, or your substrate (floor below the tile) is moving. To go into detail I will list some of the many reasons why the grout is cracking, tile crunching etc.
Tile is not bonded (stuck) to the substrate (floor). Many reasons for this. Mortar was dry when tile was set. A bond breaker, dirt, oil, wax, greese etc.
Not enough mortar on the back of the tile. Industry standards require 80-85% for dry areas and 90-95% for wet areas.
Substrate is moving. Wood substrates need to meet L/360 deflection minimum for wood substrates. Now you need to know how thick the plywood you have is and the size, spacing and span of the joists. In most cases if your joists are 16” on center and your plywood is 5/8 minimum then you should be ok if you will be installing a uncoupling membrane for your tile underlayment. This to for a porcelain or ceramic tile. If you have stone you need the floor twice as strong. L/720. To get the floor the strong in most cases you need two layers of plywood around 1 1/4” thickness. Best is two layers of 3/4” plywood making the total thickness 1 1/2”.
No perimeter expansion and contraction joints. Tile moves like everything, you have to give it somewhere to go. Your need anywhere from 1/8-1/4 around the perimeter of the floor. You can go wider if you want. As long as the base molding will cover. On wall I try not to go wider than 1/8”, IMO it doesn’t look good any wider. And you don’t want a silicone joint on your wall at 1/2” thick.
Too much water added to the grout when it was mixed or to much water use when and after washing the grout off the tile.
Substrate (floor) was not prepped to bring industry flatness to 1/8” in 10’ for large format tile and 1/4” for tile under 15” on Tiled Floors
Floor tile was SPOT bonded. This is a method where the intaller will put thick dabs of mortar on the back of the tile to make adjoining tile flat will each other. This will create voids and standard mortar only allow up to 1/4” thickness. Large format mortar can go up to 3/4”. Either way spot bonding floor tile is a good way to have a realy short time life on the total installation.
