How to Seal Around a Basin

Step 1
Use a craft knife with a new blade to slice away any old sealant. Make sure the surfaces are as clean as possible and use a cloth dampened with white spirit to remove any grease and dirt, ready for new sealant.

Step 2
Cut the tip of the sealant nozzel at 45 degrees, around 15-20mm from the end. Unscrew the nozzel and trim off the tube seal. Screw the nozzel and fit the tube into a mastic gun. Test the sealant flows out in a smooth bead.

Step 3
Starting in a corner, gently press the gun's trigger and form the bead around the basin lip with a smooth continuous movement. Keep the nozzel just above the worktop/tiles. Bring the gun quickly away from the basin edge and worktop. Work from the corners to the centre of a long run. Do not touch the sealant until it is dry, but carefully wash away spilt sealant away from other parts of the basin.

Tips & Advice
- If you're sealing around a resin bath, fill it with water first. This will make the sides of the bath deflect away from the wall. Now run the mastic around the edge and leave to dry. When you empty the bath, the sides will push back towards the wall, forming a watertight joint.
- Practice running a smooth continuous bead of sealant on the inside edge of a cardboard box.
- Most sealants will last for a few days once the pack is opened. Push a matchstick in the end to stop the end becoming blocked with dry sealant.
- Sealants dry quickly; wash your hands and the tools as soon as you've finished the job, following the manufacturer's instructions.
- If you're nervous about making a mess, make a boarder of masking tape on the basin and worktop edges. Run a bead of sealant between the tape lines and remove the tape before smoothing the edges.