Undertrowelling

Undertrowelling is a specialized technique used in the construction and maintenance of tiled surfaces, particularly in swimming pools, fountains, and other wet environments. It involves the removal of grout and thin-set mortar from between tiles to allow for the insertion of a flexible waterproofing membrane. This process is crucial for ensuring the longevity and water resistance of tiled structures.

The term "undertrowelling" is derived from the tools and methods used, which include a trowel-like instrument. The process begins with the careful removal of the existing grout and mortar, taking care not to damage the tiles. This is typically done using a grout saw or a similar tool designed for precise cutting. Once the grout and mortar are removed, the space between the tiles is cleaned thoroughly to ensure a clean surface for the waterproofing membrane.

The waterproofing membrane, often made of a flexible material such as rubber or plastic, is then inserted into the cleared spaces. This membrane acts as a barrier, preventing water from seeping behind the tiles and causing damage to the underlying structure. The membrane is secured in place, and new grout is applied to fill the spaces between the tiles, completing the undertrowelling process.

Undertrowelling is an essential step in the maintenance and repair of tiled surfaces in wet environments. It helps to extend the life of the tiles and the underlying structure by ensuring proper waterproofing. This technique is commonly used in the renovation of swimming pools, fountains, and other similar structures where water resistance is critical.