QUESTIONGood Evening: I just recently had 8"x 47" Wood Look Porcelain tile laid and I have a lot of lippage, hollow tiles, one tile has already cracked. The Box pattern states 20cm offset. It appears the first 2 lines look to have this pattern and then it drops off on the 3rd row and picks back up again, I have a open concept living and dining area (approx 50ft of area) and the contractor did not install expansion joints, I was informed because there is a small gap at the baseboards, no expansion joints are required, is this true? I did some research on my own and the TCNA states movement joints for interior applications should be placed at least every 6.1 to 7.m (20 to 25ft) in each direction unless the tilework is exposed to direct sunlight or moisture, which would then require the movement joints placed at least every 2.4 to 3.7m (8 to 12Ft) in each direction. My sub floor is concrete.
ANSWERANSWER - There are standards for what is acceptable tile lippage. Hollow sounding tiles are not a defect in itself, but a hollow sound may or may not be an indication there is an underlying defect. Tiles that are installed correctly should not crack. Expansion joints, which is a type of movement joint, may or may be required in a tile installation. But always there should be some type of a movement joint installed in all tile applications per industry standards.
Installing an 8" x 47" porcelain tile can be problematic. The long edge tends to have warpage that can lead to tile lippage. Industry standards limit how much warpage a tile can have per ANSI A137.1. It is important that the off set of planks are as required by industry standards and the tile manufacturer, as two adjacent tiles with warpage are compounding and can contributed to tile lippage. ANSI A108.02 limits how much lippage is allowed. The width of the grout joint can contribute to the tile lippage if it is too narrow. The substrate if not properly prepared can contribute to tile lippage, but it is up to the tile installer to install the tile correctly to avoid excessive lippage. The tile installer should not proceed with a tile installation if he can't achieve an installation that will be meet the standards.
Movement joints should be installed at all perimeters and transitions of a tile installation. 50 square feet is a very small area and depending on the configuration of that area you may only need perimeter movement joints. At the perimeters an open joint can be left without filling the joint if there is a base that will be covering it up. Without sealant the joint still is able to mitigate movements within the tile installation.