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Faucet

How To Seal A Sink Basin

Everything you need to know about how to seal a bathroom sink is on this page, from how to clean, apply and what mastic to use when sealing sink basins.

Why Should I Seal A Sink Basin?

When a bathroom sink is fitted there will be smalls gaps behind the sink and the sink stand if it has one. If these gaps are left unsealed water can seep through and cause some expensive problems down the line.

 

Sinks can contain a large volume of water which makes them prone to leaking or water overflowing over the edge. If water manages to seep through the small gap between the walls and floor water can stay underneath the sink basin for a long period of time causing rotting, flooding and a build up of mould that can be costly and hazardous to health. Sealing these gaps with a mould resistant silicone sealant can prevent all of the above.

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Another reason to seal/reseal your bathroom sink is to make it stand out. Old sealant can start to lose its fresh look and can collect mould over time. You can remove old sealant and apply fresh high quality mould resistant sealant to spruce up your bathroom and give your sink a brand new look.

What Do You Seal A Sink With?

To seal a sink basin with silicone sealant - you’ll need the following equipment:

  • Safety knife

  • Caulking gun

  • Mould resistant high quality silicone sealant

  • Silicone applicator tool

  • Wonder wipes

Sink Sealants 

Listed across is a range of the best sink basin sealants you can use to seal your sinks, We offer these mould proof sanitary silicone sealants in our store, they come in a variety of colours and sizes to meet your needs.

What Areas Of A Sink Do You Seal?

When sealing a sink you want to make sure you seal all of the correct areas so there is no water leakage. 

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Sink Basin-  When sealing the sink basin you want to make sure you seal the perimeter of the sink behind the tap to the wall and round the bowl that is attached to the wall or vanity unit. If the sink is fitted into a vanity unit then you would seal the whole perimeter of the sink to the top of the vanity unit.

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Sink Stand - If the sink is attached to a stand that reaches to the floor tiles you want to seal both vertical edges of the stand to the wall from the sink bowl to the floor, you will then seal around the bottom of the sink stand to the floor tiles.

how to seal a sink basin step by step

How To Seal A Sink Basin 

Step By Step

Once you’ve got your equipment and tools, it’s time to start sealing your bathroom sink.

 

Preparing the Silicone

Firstly you are going to want to find the correct mildew resistant silicone sealant from a shop. There are many good brands out there to choose from, Dow Sil is a high quality brand you can use to find the correct mastic for your bathroom sink. 

use your Stanley knife to cut the silicone sealant tube open. Before attaching the head or nozzle of the silicone, cut the tip as close to a 45-degree angle as possible, this will make applying it much easier and neater. Then place the silicone into the caulking gun and pull the trigger slowly until you feel a bit of resistant so that the tube is securely in the gun and will not fall out.

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Clean the surface

You need to make sure that before applying the silicone that the surface has no dust, residue, water or old silicone if reapplying. You can wipe the surface down where silicone will be applied but you need to make sure it is then dried afterwards because silicone will not bond to a wet surface.

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Apply the sealant

Get as close as possible to the edge of the area you want to seal, and then apply the silicone by pressing the caulking gun trigger. In a smooth movement, begin from one end and work you way to the other end. Do not touch the sealant once you have have applied until you have sealed the whole area. When finished Applying click the leaver on the back of the sealant gun to loosen the tube and stop sealant from oozing out the nozzle. Cover the end of the nozzle so no excess sealant spills on the floor.

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Smoothing the sealant

Now spray the sealant you have applied with water (Water helps remover the excess sealant and stops it from sticking), then grab your sealant tool and attach the correct head onto it with the rounded radius you desire. Start from one end by putting the flat edge onto the sink or the wall and then gently push the tool up against the corner, then slowly glide along the sealant bead keeping one edge flat. As you pulling the tool along it will be taking up excess sealant so have a paper towel ready so when the sealant builds up you can bring the tool away from the area and wipe off the excess sealant and start back where you left off until the perimeter of sealant is complete. When you are sealing around the sink bowl you will not be able to use the sealant tool properly, you can wet your finger and get rid of the excess with the same method. Your sink should now be sealed properly. you may want to have a look over and run the tool over any bits that are a bit wider or need slight touching up. If there are gaps this is no problem you can re apply and start the process again in that small area. 

Give the sealant 24 hours to cure do not run any water or disturb the sealant during this time.

Removing Old Sink Sealant 

To remove old sealant you will need a Stanley Knife a small scraping tool, sealant remover and some sort of cloth. 

Start by running the Stanley blade down the centre of the sealant, next scrape away as much sealant as you possibly can using the scraper (be carful not to damage the sink basin or tiles whilst doing this). Apply the sealant remover to the left over bits of sealant and leave it for 15 minutes. 

Now you can rub over the sealant with a cloth and it should peel away quite easily. 

The sealant removing process is a lot more time consuming than applying sealant. Once you have finished removing all sealant you can now clean down the area and re apply.

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