Atlas Elastic Sanitary Silicone Sealant

Silicone for the joints that grout cannot hold: tiles to bath, tiles to shower tray, tiles to worktop, and the internal corners of a tiled enclosure.

Those joints move. A bath flexes as it fills and empties, a tray settles under someone standing in it, and a worktop moves with the units below. Grout is rigid and cracks there within months, which is why a bathroom that looks perfect on handover shows a hairline crack along the bath by the following winter. Silicone stays flexible and absorbs that movement.

The sanitary formulation matters in a wet room. Ordinary silicone goes black along the edges once it is wet every day; a sanitary grade carries a fungicide that holds mould off far longer. It bonds to ceramic, glass, enamel and most sanitary surfaces.

Cut the nozzle to the joint width, run the bead in one pass and tool it straight away before a skin forms. The common mistake is applying it over an old joint: silicone does not bond to silicone, so the new bead lifts within weeks. The resealing guide covers getting the old one off properly.

For the waterproofing that goes on behind the tiles, see the tanking range.