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Knowledge Centre


Learn all you need to know about grout & epoxy here by clicking any of the questions below to reveal their answers and click again to hide them.

To access other topics in the Knowledge Centre, click the book icon below.

The basics...

Why is silicone required?

Silicone is required to seal any areas where liquids may seep between tiling and sanitary ware (e.g. around baths) due to its waterproof qualities and flexible capabilities. Grout would not provide the flexibility or waterproof qualities necessary, particularly at places such as internal angles and movement joints.

What colours are available? 

There are a variety of colours available and most manufacturers will have a range of colours to match with or complement their grout colour range. We stock 50 colours to match the grout colours we stock for example.

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What Silicone colour do I use if there isn't one to match my grout colour?

You can grout the internal angles and then use a transparent silicone over the top to maintain consistency in colour and a white silicone around the sanitary ware (assuming the sanitary ware is white. If not an appropriate matching silicone could be used).

How do I apply silicone?

When you begin applying silicone, start without cutting any or a small amount off at an angle. Make sure you do not cut too much off of your nozzle! Next, practice applying the silicone in an inconspicuous area first is advisable and use a profiling tool to create a smooth and clean finish. There are various profiling tools available that can aid the application of silicone, each offering a variety of profiles, widths and finishes. Some require a soapy solution to be applied after the bead of silicone has been applied but before the profile tool is used, while others require no further treatment.

Do NOT wet your finger during application by inserting it in your mouth as you can get silicosis from doing this, which may prove fatal. Instead, use your finger dry if you are doing it this way.

See tips on storing your opened silicone tube below.

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Can silicone be used in swimming pools?

All of our stocked silicones at MTM Tile Showroom can be used in a swimming pool. However, some silicones are not recommended to be submerged constantly. Always check with the manufacturer.

Can silicone be used as an expansion joint as opposed to using a pre-formed one?

Yes, silicone is often used as an expansion joint and is in fact an ideal product for this application.

Are there any tools that can help with the smoothing of silicone?

There are various profiling tools available that can aid the application of silicone, each offering a variety of profiles, widths and finishes. Some require the use of soapy water and others do not. There are often videos on YouTube for reference and instruction.

How do I apply silicone in hard-to-reach areas?

You can purchase separate nozzles that are extended and/or can be angled for difficult-to-reach areas such as behind taps etc.

How do I store an opened tube of silicone?

Some silicone nozzles come with a screw-on cap to keep the air out. For those that do not, the best methods to adopt are as follows:

  • You can insert a nail or screw in the nozzle to keep it airtight and ready for the next use. 


  • You can allow the silicone to come out of the nozzle end and let this cure naturally, thus creating an airtight seal. Prior to use simply pull the cured silicone from the nozzle and it is ready for use.

It is worth noting that opened tubes of silicone will not store indefinitely. so please check if the silicone is okay before reusing it. 

How do I clean my silicone?

It is best to use a pH-neutral cleaner. Available from most good tile showrooms.

What silicone do I need to use with natural stone and why?

A neutral curing silicone would be required for use with natural stone.

Are silicones antifungal and therefore mould resistant?

Some silicones are indeed antifungal and will protect against mould and bacteria growth. This does not replace the need for regular cleaning and will not totally prevent any build-up if left damp for long periods.

How do I remove mould from my silicone?

There are various mould-removing sprays on the market. It is best to purchase this from a tile showroom as it will not contain ingredients that may damage the grout.

What is a neutral curing silicone?

A neutral curing silicone does not produce Acetic acid when it cures and prevents any of the silicone elements from leaching into the stone and therefore discolouring the stone.

What is leaching?

Leaching is where a substance has been absorbed by a porous material such as stone via capillary action and caused irreversible staining.

What acid does silicone produce when curing?

Silicone produces Acetic acid whilst curing.

The corners of my bath and shower are grouted, do I still need silicone?

Yes, you will still require silicone as any movement, however slight, will crack the grout and allow the ingress of water.

How long after the silicone has been applied can I use my shower?

Silicone takes 24 hours to cure, although where it is possible, we would recommend a wait of 48 - 72 hours before use.

How do I remove old silicone?

There are tools specifically made for the removal of silicone but, great care is required when using these tools as anything made of metal can damage the surrounding area if not used correctly. There are plastic tools available that will help limit or prevent such damage. You may still require a window/glass scraper (a small scraper designed to hold a utility knife blade) to remove all residues.

There are also products that will break down the silicone, making it easier to remove. Please carefully read the instructions when using these products.

Whichever way you tackle it, you will need to ensure all traces of silicone are removed to enable you to achieve a satisfactory result once the new silicone is applied.

How do you clean off excess silicone when it is wet?

You can remove excess silicone with specifically designed wipes that aid in silicone removal or kitchen roll (or similar) can be used with care. This must be carried out immediately as once a skin has formed over the silicone it will be impossible to get a smooth finish.

Should I leave a gap between my sanitary ware and tiles for siliconing?

Yes, a gap of 3mm is advisable to prevent possible damage to the tiling due to any possible movement.

What is the recommended gap for internal walls for movement and where silicone is to be applied?

As per British Standards, the recommended gap in internal angles should be a minimum of 6mm. Silicone is then applied to these internal angles.

Should I fill my bath up overnight prior to siliconing?

Filling your bath prior to tiling is a good idea if possible, as it will allow the bath to settle before applying the silicone whilst alleviating the possibility of stress on the silicone joint at a later stage.

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