Basement waterproofing methods – 2 most popular options

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basement waterproofing methods

In this article we will be looking at two basement waterproofing methods, that can turn your damp basement into a useable room.

Whether you want to use your basement for storage, that will not destroy your belongings with damp and mould.

Or maybe you want to create a new room, such as an additional bedroom, bathroom, or a games room.

Whatever your goal is, waterproofing your basement can make either possible. It can turn a damp unused space into a functional room that no longer suffers with damp.

Why is your basement damp?

Basements are often damp cold places. This is especially true in older properties, where in many cases the basement was not intended to be used as a functional room.

One of the main reason’s basements are damp, is that they are set under ground level. This means that they are subject to penetrating damp from ground water.

Problems can occur due to normal water levels in the ground. They can also become worse when rainwater saturates the ground and causes the water table to rise.

Water will usually enter the property through capillary action, moving through the pours in the masonry and foundations. It is also possible that there could be cracks, or other defects that are allowing excess moisture to enter.

Another form of basement moisture can come in the form of condensation. In most cases a basement will be a poorly ventilated space. This means that warm moist air will be trapped due to poor airflow and circulation.

As warm moist air hits cooler surfaces in the basement, it will condense and turn back to liquid water. This will settle on walls, floors, and ceilings causing condensation damp and eventually mould will start to form.

As we have mentioned previously, there are two basement waterproofing methods that are very common here in the UK. You can learn more about these two methods below.

Basement waterproofing method 1

The first way of waterproofing a basement is probably the most popular. This method is popular for two main reasons:

  1. It is relatively cheap
  2. It can be done as a DIY project

This involves waterproofing your basement with a tanking slurry.

Tanking slurry is a cement based waterproof coating. It can be applied to surfaces to create a fully waterproof barrier. This makes it a great solution for basements that are suffering mild, to moderate levels of damp.

Tanking slurry is easy to apply and does not require any specialist skills. It will just require you to roll your sleeves up and get stuck in for a few hours.

In most cases, the tanking slurry will come in powder form. This will just need mixing with water and then it can be applied to the walls with a brush.

Popular brands such as KA tanking slurry come with easy to follow step by step instructions. This means, that even someone with basic DIY knowledge can apply a tanking slurry.

To form an effective barrier, you will need to apply two coats. The second coat should be applied in the opposite direction to the first.

So, for example, you would apply the first coat horizontally and then the second coat would be applied using vertical brush strokes. This ensures that you achieve the best coverage and don’t leave any weak points or gaps in the slurry.

Finishing your tanking slurry

Tanking slurry is usually grey or white and it forms quite a rough finish. For this reason, you may want to apply an additional finish, if you intend to use the basement as a room.

If on the other hand, you are just using the room for storage, then you may leave the slurry as your final finish.

Below are a few options to finish your tanking slurry:

  1. Paint directly on to the tanking slurry. This can be done with a standard emulsion. You can read more about the correct way to paint tanking slurry by clicking here.

  2. Adding a render over the top and skimming to create a smooth finish.

  3. Dot dab boards over the top of your slurry and then skim. You may want to consider using a different type of board adhesive to get a better fixing to the tanking slurry. You can read more about dot dab over tanking slurry here

  4. Build a stud wall or fix timber batons to the wall, then board over and skim.

Apart from the first option, where the slurry is just painted, you will probably need to hire a professional plasterer to help you achieve a high quality finish.

Once you have achieved your desired finish, you can paint with a standard emulsion.

Basement waterproofing method 2

The second basement waterproofing method is more technical. This involves the installation of a membrane and a drainage system.

A plastic membrane is attached to the walls of your basement. This membrane sits into a drainage channel.

When water penetrates through the wall, it runs down the back of the membrane and is collected in the channel. Next it runs from the drainage channels into an underground sump tank. From here the water is pumped out to an outside drain.

This whole process is quite technical and will require the help of a professional to install. This is not something you should attempt on your own unless you have prior experience.

The floor of your basement will need excavating to install the sump pump. This process alone can cause additional damp problems if installed incorrectly.

You can easily get online quotes from local basement specialists to get an idea of the price.

We recommend Bark for this. They are a comparison site where you can get up to 5 online quotes from local professionals and we have seen some really good prices.

This is mainly because you receive multiple quotes, and each professional is competing to offer the best price. Each company also has a profile, so you can see all their reviews from previous customers.

To get up to 5 online basement tanking quotes click here.

Removing condensation from your basement

Whichever method you use to waterproof your basement, there is still a good chance of damp forming due to condensation.

In general, basements have poor ventilation and airflow. This can lead to condensation forming and mould growth. Obviously, this is a problem you want to avoid, so you will need to take steps to remove moisture in the air.

In a basement, the best way to do this is usually installing an extractor fan.  A good option can be a humidity controlled extractor fan. This will turn on automatically when air humidity rises above a certain level.

The main advantage of using an automated extractor, is you do not have to constantly remember to turn it on and off. You can just leave it and the fans programmed settings, will keep the air humidity at the desirable level.


These are the two most common basement waterproofing methods we see used in UK homes. In most cases, a tanking slurry will be enough to give complete protection from damp penetrating your basement walls.

However, if you have a very wet basement, we do recommend considering a membrane drainage system. If in doubt one option is to have an independent damp survey. This will cost £100-£200, but a professional damp surveyor will give you an honest recommendation of the best solution.

We also recommend Bark for damp survey quotes.

Click here to get 5 local damp survey quotes now