Floor Tile Deflection Normal

Prepping wood framed floors for tile.

Floor tile deflection normal.

Answer answer the fact that there is a squeak under the tile suggests that the wood underlayment subfloor is moving to some degree. The adhesive bond that secures the tiles the setting bed on which the tiles are installed the structure that holds everything up and a grid of flexible movement joints that help isolate the installation from normal expected structural movement. Adding plywood cuts deflection by about 80 percent. When applied the standard taken in isolation can mean that slopes in excess of 1 inch over a 15 foot span are acceptable.

Most tiles comply with astm c648 breaking strength standards. Normally this is avoided if when the wood subfloor underlayment is installed it is glued and screwed so there isn t any movement or chance for there. The long term success of any tile floor installation depends on a number of factors. As long as the tile does not break under 250 pounds of pressure the tile is considered to be compliant with these standards.

A low pitched sound can also occur and not signify there is a problem the type of sound you hear also depends on the configuration of the tile assembly for example when tile is installed over a less dense substrate as in the case of wood a non bonded mortar bed a sound control mat or other membrane or over a steel framed wall. Deflection or bounciness can cause tiles and grout to crack or come loose and the tolerance depends on what type of tile is being installed. It is for this reason that recommendations for floor rigidity are not based on deflection measurements but on empirically established methods found to work over normal code construction. For instance ceramic tile can withstand more deflection than natural stone.

In fact failures at l 600 have been observed. Depending on a number of factors if you have a floor that spans 10 feet in length then a defection of a 1 4 or 1 3 of an inch might be acceptable. The american national standard specifications for installation of ceramic tile ansi a108 states total load deflection not the code minimum total load deflection of l 240 criterion should be l 360. Most tiles meet the 250 pound minimum.

Calculating deflection many tile contractors can judge a floor s deflection by walking around. A low tone is not a cause for immediate panic however. Ansi a108 section an 2 3 deflection. Floor areas over which tile is directly bonded to subfloor shall not have a deflection greater than.

Recent research has shown tile to fail under some conditions when the floor is more rigid than l 360. The asce defines the deflection ratio as the maximum distance from a straight line drawn between 2 points on a foundation and the surface of a foundation. It makes the floor stiff without creating obstructions in the basement but it s more expensive 8 to 12 per joist than other methods and won t work if you have plumbing or electrical lines mounted to the underside of the joists.