The growth of heated floors has dramatically increased the number of enquiries we receive on the subject of movement accommodation for heated surfaces.

 

To bring some clarity to the situation we would put forward the following observations.

 

The relatively rapid expansion and contraction in these installations is the main cause of failure.

 

In electrical surface heating this movement is passed directly to the tiled surface. The subfloors movement lags behind. This movement can cause tiles to crack and the adhesive bond to break.

 

With wet systems the heat in the water pipes passes into the screed and then more gradually into the tiled surface. This expansion and contraction within the subfloor can frequently cause cracking in the screed, which in turn causes cracking in the tiled surface.

 

A solution that works for both situations is the isolate this thermal movement from the tiles using a de coupling membrane – CI Matting.

 

This “underlay” prevents the stress in the installation by absorbing it within its air channels.

 

In effect whatever is happening in each layer of the installation is isolated from the surface tiled layer.

 

Having made provision for any movement from the substrate consideration should be given to the actual tiled surface.

 

The first consideration is to follow through in the tiled surface any pre – existing joints in the sub floor. (The matting should be split at these points).

 

After this has been done the prospective fields should be looked at. The latest – best advice from the Tile Association is to create fields with a maximum size of 3.5mtr x 3.5mtr. There is no need to split the CI matting where surface movement joints have been placed to achieve these dimensions.

 

Please be aware that it is also very important to create movement joints at the perimeters of any floors in excess of 2.mtrs x 2mtrs.

 

We can supply colour co ordinate joints to minimise the aesthetic impact within the floor surface.

© 2010 Dural (UK) Ltd