Marley Alutec Silicone Sealant 310CC Clear SC101

Sealants fill joints and gaps to keep out water, draughts, noise and dust, and help hold fittings such as baths steady. This category covers bath and kitchen sealants, sealant and adhesive cartridges, indoor and outdoor gap fillers, heat-resistant sealants, tile grouts and sealant guns, plus some vehicle products such as tyre puncture sealants.

Which sealant

• Silicone: the usual choice for wet areas and smooth surfaces such as tiles, glass, baths, basins and shower trays. Bathroom versions resist mould. Paint will not stick to silicone, so do not use it where the joint will be painted.
• Acrylic: paintable and low odour, used indoors for joints around skirting boards, stairs, floorboards and window and door frames, but not for joints that stay wet.
• Sealant and adhesive: hybrid cartridges that seal and also bond, useful where a fixing and a seal are needed together.
• Heat-resistant sealant: for joints exposed to high temperatures. Check the temperature rating on the cartridge against the job.
• Grout: fills the joints between tiles. Choose wall or floor grout to suit the job, and a quick-setting type if the area is needed back soon.

Getting a good seal

Cut out all the old sealant, clean off any residue and mould, and let the joint dry fully before you start. Apply a steady bead with the nozzle at roughly 45 degrees and smooth it with a tool. When sealing a bath, fill it with water first and leave it full while the sealant cures, so the bath is already at its loaded position. Leave the curing time stated on the cartridge, often a day or more, before the joint gets wet. Follow the manufacturer's instructions and safety data.

For bonding rather than sealing, see adhesives, or browse sealants and adhesives.