How to apply bathroom sealant

Use a utility knife or silicone removal tool to carefully cut and remove the existing sealant. Take care not to damage surrounding tiles, surfaces or fixtures. Remove as much of the old sealant as possible, as new silicone adheres best to a clean surface. Once the old sealant has been removed, brush or wipe away any loose pieces of silicone, dust and debris. Even small remnants can affect the adhesion of the new sealant and impact the finished appearance.

Wipe the joint thoroughly using methylated spirits or a suitable cleaner to remove soap residue, oils and dirt. Allow the area to dry completely before applying new sealant. Silicone should never be applied to a damp surface, as moisture can affect adhesion and lead to premature failure.

Apply masking tape along both sides of the joint, leaving an even gap where the silicone will be applied. This helps create cleaner edges and can make it easier to achieve a professional-looking finish, particularly for first-time D.I.Y.ers.

Select a wet area silicone sealant suitable for bathrooms, laundries or kitchens. These products are designed to provide a waterproof seal and often contain mould-resistant properties to help keep the finished joint looking cleaner for longer. Sealants are available in a range of colours, so choose one that complements the surrounding tiles, grout or fixtures.

Load the sealant cartridge into the caulking gun and cut the nozzle at a 45-degree angle. Start with a smaller opening, as more sealant can always be applied if needed. A smaller nozzle opening often provides better control and helps avoid applying too much product when resealing a shower.

Before starting, test the flow on a piece of cardboard or scrap material to get comfortable with the pressure required. Hold the nozzle at a consistent angle and apply a continuous bead of silicone along the joint in one smooth pass. Moving too slowly can result in excess sealant, while stopping and starting may create uneven sections in the silicone bead.

While the silicone is still wet, lightly spray the bead and the silicone smoothing tool with a mixture of water and a few drops of dishwashing liquid. This helps the smoothing tool glide smoothly over the sealant and can make it easier to achieve a neat, professional-looking finish.

Run the smoothing tool along the joint using steady, even pressure in one continuous pass where possible. Wipe excess silicone from the tool regularly to avoid dragging it back across the finished surface. If there are small bumps, ridges or uneven areas, simply spray the area again and make another smoothing pass before the silicone begins to skin over. If a section has too little silicone or a gap has been missed, apply a little more product and smooth it again straight away. Working in small sections can help maintain control, particularly when tackling longer joints.

Once the joint has been smoothed, carefully remove the masking tape while the silicone is still wet. Pull the tape away slowly at an angle to help create a clean edge. Check the manufacturer's instructions for silicone curing times before exposing the area to water. Most bathroom sealants require a curing period to achieve a fully waterproof seal. Avoid using the shower, bath or splashback area until the sealant has cured completely, as introducing moisture too early can affect the finished seal. Once cured, the new sealant will help protect against water ingress while giving the area a fresh, clean finish.