How much does waterproofing cost?

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Price guide

£40 - £250







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Moisture is an annoying, year-round problem, and it can heavily damage your basement.

Don’t worry. You can protect your basement or cellar from moisture through waterproofing. These rooms tend to be colder and damper than other parts of your home because they are below the ground.  

In the UK, the average basement waterproofing cost per square metre is £120. You’ll not only protect your foundation from flooding but also have additional storage or functional space in your home. This guide will discuss what affects basement waterproofing membrane costs.

Basement type 

(floor, wall, and ceiling height)




Average basement waterproofing per m2




4m x 5m x 3m walls




5m x 6m x 3m walls




6m x 7m x 3m walls




a man waterproofing a basement's flooring

What factors affect waterproofing costs?

Read on if you need an estimate of waterproofing costs per square metre. 

The size of your space

The larger the basement, the higher the cost of waterproofing. On average, waterproofing costs £120 per square meter. So for a 4x5 metre basement with 3-metre high walls, expect to pay £8,000. If you have a 5x6 metre basement, the cost is around £10,500. For larger basements of 6x7 metres with 3-metre walls, the average price is £17,500. 

Prep or structural work

Before the actual waterproofing process, you need to examine or survey the basement. Some waterproofing specialists will do it for free or include it in the service package. However, if they charge you, it costs £100 to £200.

The existing wall and floor construction also determine the waterproofing products suitable for the basement.

The shape of your basement

Most basements are rectangular, but some awkward room structures have special requirements, thus increasing the overall cost of waterproofing. The digging process is simpler and cheaper if the basement is open to one side.

Vaulted, pitched, or arched ceilings cost more waterproof than flat ones because they require meticulous work.

The purpose of your basement

Suppose you want to make it a bedroom or busy space. In that case, you need to consider additional costs to make it safe or habitable. For instance, you must comply with other building regulations affecting the contractor's waterproofing method. 

A contractor will waterproof your basement using a cavity drain membrane system (including a sump and pump) if you want a functional room. Do you only need to keep the basement dry? In that case, the contractor will use a cementitious tanking system, which costs less.

Waterproofing membrane

A waterproofing membrane is a thin layer of material protecting the walls or floors of your basement from water or moisture. The quality of the waterproofing membrane also affects the project's overall cost.

Time requirements

The project's complexity can increase the contractor's labour costs, thus affecting the total price.


Some areas in the UK have higher costs of living. In London, you might pay 10-20% more than usual. If your contractor needs to travel outside their standard designated area, expect to pay for their transportation. Busier regions also have high parking fees.

Waterproofing price list

Getting into specific details helps you compare prices and evaluate your budget. Here's a list of typical waterproofing costs:

According to tanking method

Tanking type 


Professional installation (per m2)

Internal tanking

Using a waterproof coat to stop water from entering

£40 to £80

External tanking

Requires extra labour, such as excavating the outer walls of your basement or cellar

£30 to £40

Injection damp-proofing

Includes dry rot treatment, timber treatment, and re-decoration

£2,000 (estimate total)

a man attaching waterproof tape to a basement wall

Additional costs for waterproofing

  • Renting or hiring a dehumidifier to speed up drying costs £65 to £85 per week. 
  • If you’re buying the materials yourself, the price of a waterproof sealer is £25 to £85 per five litres.

Other issues

If you need a more accurate quotation from your contractor, relay as much information as possible. It helps your contractor determine all the necessary methods and materials. Here’s a list of things to check:

  • Water pipe leaks
  • Cracked foundations
  • Improperly graded slopes around the house
  • Poorly designed window wells

What are my options for waterproofing?

Stop severe problems in your basement by using quality products or combining solutions.

  • Dehumidifiers. For minor moisture problems, buying or renting a dehumidifier might help.
  • Waterproofing Products. You can ask your specialist about using waterproof paint, sealant, or other products on the interior of your basement to stop moisture from penetrating walls. Waterproof paint costs £20 to £200 per can.
  • Gutters and Downpipes. Make sure your downpipes and gutters are functional. They direct all of the water from your roof to the basement. Installing new ones cost additional pounds, depending on the size of your home.
  • Window Well Drains. Improperly designed window wells also cause basement dampness. So replacing them can help solve your problem.

Waterproofing quotes from Taskers

Relative to the size of the basement and its current condition, waterproofing tasks from Taskers can cost only £50 to £110. You can get a more accurate quotation. Just reach out to a Tasker and provide the details of your waterproofing requirements. 

Overall, basement renovation doesn't have to be problematic. With a Tasker, you can save time and complete your waterproofing project nicely. Post a task and connect with a reliable Tasker in minutes!

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