Silicone is often used as a sealant in the bathroom or kitchen to prevent moisture from getting behind the bathtub or sink and causing mold.

However, because silicone becomes porous or leaky after a few years and even starts to mold itself, it needs to be replaced regularly. As a rule, this should be done after five to eight years at the latest. Old silicone joints not only look ugly, they can also damage the building structure if water gets behind the tiles. To replace old joints, however, the tiler does not have to come to the house every time – even beginners can easily renew them themselves. These 5 steps will show you how to do it and what to look out for when replacing your silicone grout:

1. Remove old grout

As good as silicone is at sealing, it’s unfortunately difficult to remove. To renew porous or leaky silicone joints, however, the old silicone must first be loosened from the joints. There are several ways to do this:

  • With a knife

The most common method is to remove the silicone residue with a knife. Use a special joint scraper or a cutter knife and remove the old silicone completely.

  • With silicone remover

If old silicone cannot be completely removed with a cutter, another method must be used. In this case, try using chemical silicone remover. This is available as a spray, a gel or in liquid form. Apply the remover to the porous silicone and let it work according to the instructions. The silicone can now be easily removed with a sponge. When using silicone remover, make sure that there is sufficient ventilation and clean the surface afterwards with methylated spirit to remove the residue of the agent from the joint. If you don’t want to use strong chemicals, you can also remove the silicone residue with vinegar, baby oil, dishwashing liquid or a dirt eraser. Commercially available nail polish remover is also suitable for removing silicone. However, its use can produce vapors that are harmful to health.

2. Masking the edges

Once you have removed all the silicone from the joint, clean the surfaces and then allow them to dry thoroughly. Then tape the edges along the joint with masking tape to ensure clean edges when applying the new silicone later.

3. Apply primer

To increase the adhesion of the silicone later, it can be helpful to apply a primer beforehand. This is easiest to apply with a small brush and must then be left to work for a few minutes. In the meantime, you can prepare the cartridge with the silicone. Cut off part of the tip at the front and place it in the cartridge gun.

4. Draw new joints

Once the primer is dry and the cartridge is ready to use, you can start. Be sure to keep the pressure constant and move the silicone gun at the same speed without stopping to draw an even joint. There should be no voids in the silicone, otherwise moisture can get behind the tile and promote mold growth. Also, don’t be too sparing with the silicone and add about 0.07 inch to the width of the old grout line, because silicone shrinks a bit over time.

Tip: If you are not using the silicone gun at the moment, you should loosen the tension spring at the end so that the silicone compound does not continue to be pressed out.

5. Smoothing the joints

After you have filled the joint evenly, you need to smooth out the silicone. As a rule, no more than ten minutes should elapse between application and smoothing. You will find the exact information on the cartridge. Spray the still liquid silicone with a little soapy or vinegar water and smooth it out with a joint smoother or, alternatively, a popsicle stick, which you also dip into the soapy water beforehand. Small irregularities can be removed with your finger, which you should also dip in the soapy water beforehand so that it glides over the silicone more easily.

To prevent the new silicone joint from peeling or tearing, it should dry for 24 hours before coming into contact with water. In addition, you should make sure that no silicone compound or remnants of the old joints get into the drain when you renew the gaps around the sink or your bathtub. Silicone is very difficult to biodegrade. Therefore, as a precaution, close the drain and dispose of all silicone residues in the household waste.