Month: January 2018

Is tile and grout waterproof?

Here at UK Pro Tiling Training, we hear a complete variety of questions about tiling and grout. Although we work with professional tilers, we also work with those completely new to tiling and are familiar with being posed basic questions, all the way to more complex ones.

One of the questions we are often asked by customers and those tilers new to the industry, who are perhaps attending one of our tiling courses, is: Is tile and grout waterproof?

Water ripples on blue tiled swimming pool background. View from above.

The answer to the question is, surprisingly, no. Tile and grout is not totally waterproof and neither is cement board, backer board, sealers and cement adhesives, they absorb water but do not block penetration.

Even if you don’t work in the tiling industry, you may be familiar with the sight of mould and mildew growing on the edges of tiles and baths in bathrooms where there is insufficient ventilation or in bathrooms where users have many showers, although the bathroom has been built for mainly having baths.

So why is tile and grout used in kitchens and bathrooms?

Most tile and grout products are moisture proof which is, of course, not the same as being a waterproof product but does mean the materials can be used in kitchens and bathrooms.

There are other methods that can be adopted to make shower rooms and other wet tiled areas, waterproof such as latex tanking systems.

This is where tilers, builders and plumbers can work together to ensure a shower area is completely waterproof.

How can tile and grout be made waterproof?

Grout sealer is a fundamental part of the tiling installation process and helps prevent water getting into the grout and under the tiles.

Essentially, most grout is made of sand and once dried and in place between the tiles, is ready and set to absorb water.

Grout sealer can be applied to grout in order to deter it from absorbing the water.

Ultimately, grout sealer is a highly important part of the tiling installation process and should be applied in the majority of projects.

Remember: Grout and grout sealer can be a laborious task. The smaller the tiles, the longer the project will take to grout. Mosaic tiles, for example, are best applied by professional tilers who can carry out a professional application.

Also, you should only apply grout sealer to grout that is 100% dry.

Is grout sealer always needed in a tiling project?

The only case whereby you will not need to use grout sealer is when you are using epoxy grout.

Epoxy grout does not need any further additives in order to prevent the grout absorbing water as it also features water repellent properties, this would be used in swimming pools or any place that could a high level of cross bacteria contamination such as a professional catering kitchen or hospital.

Methods of apply a grout sealer

There are three main methods to apply grout sealer. These are:

1. Using a brush for the application.

Brushes tend to be the first method you think of when applying grout sealer. Although they are easy to come by, many tilers find that brushes are hard to use when applying grout sealer, due to issues of the solution running of the tip etc.

2. Rolling on the grout sealer.

Rolling is a convenient way of applying the grout sealer, it is best to roll in a downwards motion and make sure you stick to the seam. Many tilers prefer rollers to brushes.

3. Spraying on the grout sealer.

While spraying seems to be the quickest way of applying grout sealer (the spray, in theory, shouldn’t soak into the tiles, only the grout), you will need to clean the tiles down later on to make sure there is none leftover on your tiles.

More information from UK Pro Tiling Training

If you have a tiling project coming up and would like to investigate the best grout sealant for your job, then please do not hesitate to contact us at UK Pro Tiling Training.

How do you mix grout?

Grout is an essential element of any tiling project and how the grouting part of a project is completed makes an overall difference to the end result.

After all, you can purchase the best tiles and apply them evenly, and then ruin the overall look with a poor grout application.


Follow these steps on how to mix grout for a superior tiling project:

Choose your grout wisely

There are four different types of grout available for ceramic tiles and you should choose the one most suited to your particular project.

The main types of grout are:

  • Fine sanded grout
  • Unsanded grout
  • Epoxy grout
  • Quarry type grout

Fine sanded grout tends to be suitable for applying to wider spaces between tiles (between 1/8 and 3/8 inch wide), while unsanded grout is better for narrower gaps between tiles. Unsanded grout is suitable for gaps that are less than 1/8 inch wide and smaller.

Quarry type grout contains a courser type of sand and is best for tile joints between 3/8 to ½ inch wide.

For larger spaces between tiles, particularly when working with polished stone, an epoxy grout is probably the best grout type. Epoxy grout is highly resilient to stains and chemicals, and is ideal for surfaces like kitchen counters.

Epoxy grout features an epoxy resin and hardener, and can be more difficult to work with than other grout types.

Mixing the grout

If the grout you have bought doesn’t feature a polymer grout additive, then you may want to consider adding one before the mix is applied. Adding such an additive can help with the grout’s durability.

Read the instructions

Below is a general guideline for cement grout, however, it is always highly necessary to read the product information carefully before working with the grout.

Epoxy grout is slightly different so please do read the information on your grout packaging as carefully as possible.

Materials you will need

Make sure you collect the following items and have them accessible and handy for the whole of the project.

  • Gloves
  • Empty bucket
  • Sponge
  • Container of water
  • Pointer trowel
  • Margin trowel
  • Mixer paddle drill (if you have one)


Here are the steps on how to mix the grout:

  1. Place the amount of grout powder you require in the bucket. The amount of powder you need for the space you are covering should be clear on the packaging.
  2. Add ¾ of the total amount of water needed for the area you”re working on.
  3. Use a trowel or the mixing drill to stir the grout.
  4. Stir the grout mixture into a thick paste that contains no dry lumps, it may help to tilt the bucket towards you and frequently scrape the sides. Take care not to create too many air bubbles.
  5. Use the sponge to drip in extra water, take care to get an accurate consistency (not too watery).
  6. Leave the grout for 5 to 10 minutes to strengthen and then give it a stir before applying.
  7. Use a grout float to apply the grout.
  8. Clean with sponge and fresh water
  9. You should make sure you use the grout immediately as most grout sets in around 60-90 minutes. If you are tiling a particularly large area, you may want to make half the grout at a time.

More advice on how to mix grout from UK Pro Tiling Training

 Should you require any further information on how to mix grout, then feel free to contact us at UK Pro Tiling Training.