Can you tile over tanking slurry? Is it the best solution?

Tanking slurry is a versatile product that can be used for a variety of different projects. The slurry creates a watertight barrier, that will stop moisture from passing through its surface. Due to this, it is very popular for things like tanking basements, garages, and any other area that is prone to penetrating damp.

Penetrating damp usually comes from the outside. But damp can also penetrate from the inside, especially in high moisture areas, such as a bathroom or kitchen.

Due to this, it is very common to have tiles in these areas, to add a layer of waterproof protection.

For example. You wouldn’t have a shower cubicle with painted plaster walls. Instead, you would tile the area to make it water resistant.

can you tile over tanking slurry

However, tile grout and tile adhesive are water resistant, but not 100% waterproof. This means you will usually want to add an additional layer of protection underneath the tiles.

Tanking slurry can be a good option before tiling. You can tile straight on to the slurry once it is dry, and a decent tile adhesive will have no problem getting a good fixing.

The slurry itself is 100% waterproof, so even if moisture gets through the tile grout and adhesive, it will not penetrate the surface underneath the tanking.

What type of tanking should you use under tiles?

The type of tanking you use, will depend on the surface you are applying it too. If you are applying over a render, then you could use a standard tanking slurry, such as KA tanking slurry. This product can even be used in large tiling jobs, such as tiled swimming pools, so it is definitely up to the job.

Application is extremely simple; the slurry comes as a powder and is mixed with water. Following this you can apply it to walls with a brush or roller. Apply two coats and allow to dry for 24 hours.

Once dry you can tile over, and the area will be completely resistant to water.

If you are applying tanking to boards, then you could still use a general tanking slurry. However, there are dedicated solutions, and most tilers would opt for a wet room tanking kit that is specifically designed for this job.

A good bathroom tanking kit will usually come in three parts.

  1. A base primer – This is applied to the surface first and will prime porous/semi porous surfaces ready for the tanking.

  2. Tanking tape – This is used to seal any joints in boards and corners.

  3. The tanking membrane – This is the last step and should be applied after the primer has dried, and all gaps have been covered with tanking tape.

The tanking should be applied in two coats. Once the first coat is applied, you will need to wait for it to dry before applying a second coat. Ideally, you can leave the second coat overnight, allowing it to completely dry, then you are ready to start tiling.

One of the most popular solution on the market, is a 3 part tanking kit from Everbuild.

You can click here to learn more and read customer reviews

Best alternative to bathroom tanking kits and tanking slurry

So far, the two options we have mentioned involve tiling over tanking slurry, or a tanking membrane. However, these are not your only options.

Another great option is tile backer boards. These are a great alternative, especially if you are tiling over a stud wall that needs new boards, or even planning to overboard existing boards.

Backer boards are designed to be used with tiles and they offer several benefits.

  1. They are very easy to cut and install – Boards can be cut to size in the same way you would cut plasterboard. However, the board is tougher, as it is cement based. But you can still easily score with a Stanley knife and fold the boards. Also, a saw or jigsaw will work fine.

  2. It is designed specifically for tiling – As the boards are cement based, they provide a perfect surface for tile adhesive to bond too. Due to this, they can support over 60kg per m2 of tile.

  3. They are waterproof – Obviously, this is one of the main reasons you would use any type of tanking system beneath tiles, and backer boards don’t fall short. They will provide just as good waterproofing as tanking slurry or a wet room tanking kit.

  4. Backer boards have excellent thermal qualities – These boards are excellent at absorbing and holding heat. As a result, they drastically reduce condensation on your tiles. The tiles are warmer, so they no longer provide a suitable dew point for water to condense on.

Overall backer boards can be a great alternative to adding tile over a tanking slurry. They are quick and easy to install. There is very little mess, and they offer additional insulation values not found in other solutions.

Do you need to tank moisture resistant plaster boards?

The only thing we haven’t really mentioned so far is moisture resistant plasterboards. Many people will assume that this is the perfect solution. However, it is not the best when used alone.

Yes, moisture resistant boards will add a good amount of protection. But they are not completely waterproof, especially if you are screwing them in place. Ideally if you are using moisture resistant board, you would still apply tanking over the top.

If a wet room tanking kit is the method you intend to use, then use it in combination with moisture resistant plasterboard.

Conclusion + How to save money

You can tile over tanking slurry and in many cases, it will be a good solution. However, it is important to remember that it is not your only option.

The option you do choose, will depend on the specific circumstances.

If you are unsure what the best choice is, then it is probably best to talk to a professional.

Most contractors will give a free quote and tell you the best solution. So, if in doubt, it makes sense to get someone round to have a look.

Also, if you are smart about it, you may be able to get the work done at a big discount. You can do this by using online trade comparison sites.

Simply post the job, then tilers and bathroom fitters in your local area, will all compete for the work. You can end up getting some great deals this way.

To see our favourite comparison site for bathroom tilers, and get instant online quotes Click Here


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