Cracks in Roof Tiles

The condition of mortar set roof tiles being cracked is often the result of foot traffic, material shrinkage, problems with installation and expansion or contraction due to themal and moisture effects. Cracked tiles due to these causes are typically randomly distributed throughout the roof.

The Technical Brief #99-002, prepared by the Tile Roofing Institute (TRI), states “If the tiles are not properly aligned however, there is the potential for point loading that puts irregular pressure onto the corner, causing it to fracture. This most often happens when the tiles are applied too tightly together. Most tiles are designed to be installed with a 1/16 inch shunt or separation between the tile bodies. If this shunt is not maintained, damage from foot traffic or the expansion and contraction of the roof deck could result. Debris left in the channel during application could also result in point loading that may break the corners under foot traffic”.

The photograph below shows a painted flat concrete tile cracked across the middle. The condition visivble in the photographs below are not consistent with wind damage:

The photograph below shows a longitudinal crack down the middle of an unpainted concrete tile:

The photograph below shows corner cracks commonly found throughout most concrete tile roofs:

Another corner crack shown below: