How Much Does it Cost to Tank a Basement?

At Garratt’s Damp & Timber, we routinely carry out basement tanking. It’s an essential waterproofing technique used on properties with a below ground level. Unlike other types of damp proofing, not much is widely known about how to tank a basement in the UK, largely due to the fact that cellars and basements are not commonplace here.

That being said, there are still thousands of properties up and down the UK that do have an underground level – most of them being older, period properties. If you have a basement, you’re likely wondering how much does it cost to tank a basement in the UK? You probably also have a range of generic questions about the process.

We’re going to explain the basement tanking process, as well as how much you can expect to pay.

What is basement tanking?

First and foremost, it’s important to know what basement tanking is. Unlike some other types of damp proofing that are more surface level, basement tanking is an extensive process. In short, basement tanking involves protecting the walls from surrounding groundwater. If left untreated, the porous basement walls could start to absorb sitting water. This will not only lead to dampness, but it could also cause structural issues within the walls, and these could affect the whole house.

How much is it to tank a basement in the UK?

There are two main types of basement tanking, and the price between both fluctuates. The type you are recommended and therefore the price you pay will depend on your basement and what will work best for you. Both approaches are covered by British Standards

BS8102:2009 Type A is the most common method we use. Sometimes called cementitious tanking, Type A is relatively simple to install. First, we strip the internal walls of your basement until we reach the original base material. We then apply cement and sand render and top it with a multi-coat render. A waterproofing agent is mixed in. This could be a Sika additive, epoxy resin, or a slurry depending on the state of the basement in question. Basements are often painted bare brick, the paint will require removal prior to application of a render.

The goal of Type A basement tanking is to stop groundwater from penetrating the internal wall surfaces, ensuring there is no water damage inside your property. Where the basement sits in an area with low levels of groundwater, Type A is a viable option.

On the other hand, BS8102:2009 Type C basement tanking is more suited to properties in locations where there is a higher level of sitting groundwater. In essence, Type C tanking involves allowing water in where it is contained behind a membrane and then directing water away from your property through a sump and pump system. Due to the increased amount of work involved with Type C water tanking, it tends to be more expensive.

Both Type A and Type C tanking may require an appropriate treatment to the floor slab as well as walls. Ceilings may require treatment in some cases where vaults sit below overhead steps or street.

What affects the price of basement tanking?

There are a number of factors that will affect the overall price of basement tanking, including the type required. If you have a basement that is suffering from dampness or that hasn’t been tanked previously, your basement might already be damp. The extent of the damp damage will influence the price of the project due to the increased amount of preparation work. It could be that through a damp basement, your property is suffering from rising damp, and this will need its own course of remedial treatment.

Away from this, something else that will impact the price you pay for basement tanking is how big your basement is. Some are large and suitable for creating another level of living, whilst others are much smaller and most suited for general storage. The bigger the space, the more expensive the project will be because of the larger scale of materials and more work needed.

Basement tanking at Garratt's Damp & Timber 

Here at Garratt’s Damp & Timber, we are experts in basement tanking and regularly carry out work across London and the surrounding areas. We have years of experience and have worked across all manner of basements and underground areas.

When you call our team to help you with basement tanking, we will first carry out a site survey. This means our team will come out to your property and assess the site. The surveyor we send out will be CSSW, which means they are a certificated surveyor in structural waterproofing.

They will use their expertise and experience to come up with a quote. This is a no-obligation quote and there is absolutely no pressure on you to move forwards with us. The quote will be based on a report we put together where we will explain exactly what we found, how we propose you move forwards, the cost of the work we recommend, and how long we expect the work to take.

The price we give you will be competitive and fair based on our assessment and survey. It is not in our interest to overcharge you – we will always do what is best for your property and what will work for you long-term. We are so confident in our basement tanking solutions that we offer a 10-year guarantee.

To find out more about basement tanking, or to organise a site survey of your basement, please get in touch.