Outdoor and Pool Tiling in Nairobi: Slip, Frost and Fixing

Outdoor tiling is not indoor tiling outdoors

Three things change, and all three are invisible in a showroom.

The tile. An indoor porcelain laid on a Nairobi terrace is lethal when wet. Outdoor tiles carry a slip rating, usually R9 to R13, and around a pool you want R11 as a minimum. Barefoot areas have their own classification, A to C, and a pool surround should be class B or C.

The adhesive. External work moves with temperature and gets soaked in the long rains. It needs a flexible, external-grade cementitious adhesive, applied with full coverage rather than dabs. Dab fixing outdoors leaves voids that fill with water, and the tile lifts.

The falls. Water has to go somewhere, and outdoors that has to be designed before anything is laid. A terrace laid flat ponds, and ponded water on a tiled surface in Nairobi grows algae within weeks and becomes the slip hazard the slip rating was supposed to prevent.

Swimming pools

A pool interior is a different job again, and one where shortcuts surface fast.

The tiles are usually glass or porcelain mosaic on a mesh backing, fixed with an adhesive and grout rated for permanent immersion and for pool chemistry. Ordinary cementitious grout in a chlorinated pool breaks down, and once the grout goes the water gets behind the tile.

Waterlines and steps take the most punishment: the waterline from chemical concentration and the steps from feet. Those are the two places we specify the best material rather than averaging the whole pool.

Movement joints

The one thing most often left out on Kenyan terraces. A large tiled area in direct sun expands, and with no movement joint the compression has nowhere to go: tiles tent up in the middle or shear at the perimeter.

Joints go in at the perimeter and at intervals across the field. They are not a finishing detail, they are what stops the floor destroying itself, and retro-fitting one means cutting through a finished terrace.