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Basement Waterproofing London

Basements and cellars are prone to water ingress due to their below-ground position. Factors like structure type, depth, soil, and location all impact damp levels. That’s why effective basement waterproofing must be carefully tailored to these conditions for long-term protection.

Why Should You Consider Waterproofing A Basement?

Waterproofing a basement is essential for protecting your property from water damage, structural damage, and the long-term effects of dampness. Basements are naturally vulnerable to water ingress due to their position below ground, where groundwater pressure can force moisture through walls, floors, and joints. Over time, this can lead to damaged foundations, rotting timber, mould growth, and ruined belongings. Whether you use your basement for storage, living space, or utilities, waterproofing helps maintain its usability and adds long-term value to your home.

Beyond property protection, waterproofing also plays a key role in health and safety. Poor ventilation in damp basements can create ideal conditions for mould spores and mildew to grow, which may trigger respiratory issues, allergies, and other health concerns. By preventing excess moisture, basement waterproofing supports a healthier indoor environment and reduces the risk of costly repairs caused by rot, decay, and compromised structural elements. Working with waterproofing experts ensures the right solutions are applied based on your property’s specific needs, while professional damp proofing further strengthens your defence against moisture-related issues, giving you peace of mind and long-term protection.

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Type A Waterproofing – Barrier Protection

Type A waterproofing, often referred to as “tanking,” involves the application of a physical barrier to the internal or external surfaces of basement walls and floors. This system is designed to resist groundwater pressure and prevent moisture from entering the structure. Common materials used in Type A systems include sheet membranes, cementitious slurries, multi-coat renders, and bitumen-based coatings. A detailed assessment of the building is crucial at the design stage to ensure that the structure can handle the pressure exerted by surrounding groundwater. Type A systems are widely used for both new and existing basements where ground conditions demand added protection.

Type B Waterproofing – Structural Integrity

Type B waterproofing is built into the structure itself. It relies on specially formulated concrete that contains waterproofing additives to provide resistance against water ingress. While this method is generally effective, weak points can occur at construction joints, which may allow moisture to penetrate. For this reason, Type B waterproofing is often combined with either Type A or Type C systems (or both) to create a comprehensive, watertight solution. It is commonly specified for new build basements and below-ground structures where waterproofing performance must be integrated from the outset.

Type C Waterproofing – Water Management

Type C waterproofing is a water management system that uses cavity drain membranes (CDM) to control and redirect water rather than blocking it entirely. These dimpled membranes are installed on the internal walls and floors, guiding any ingress water into drainage channels or a sump and pump system. Unlike Type A, this approach doesn’t stop water from entering, but ensures it is safely managed away from the structure. Due to its versatility, ease of installation, and reliability, Type C waterproofing is especially popular for retrofitting existing basements and cellars prone to groundwater ingress.

Why You Should Choose Refresh As Your Waterproofing Specialists

Choosing Refresh as your waterproofing specialists means partnering with a team of experienced basement waterproofing experts dedicated to protecting your London property from water ingress and damp-related issues. Our qualified surveyors carry out detailed inspections to recommend the most suitable tanking solutions and drainage systems tailored to your building’s structure and specific conditions. Whether you need a full waterproofing system for a new development or remedial work on an existing basement, we combine technical expertise with premium materials to ensure long-lasting results and total peace of mind.

Basement Waterproofing Frequently Asked Questions

What is Basement Waterproofing?

Basement waterproofing, also known as Structural Waterproofing is a Waterproofing system designed to prevent groundwater ingress into the structure under pressure. There are various methods of basement waterproofing and each has its own set of requirements to ensure success.

What is Ground Water?

A different type of fungus altogether, wet rot is most often caused by Coniophora Puteana or Poria Vaillantii. Behaving slightly differently in their unique ways, there are some similarities to their general appearance which means their treatment is similar too. Wet rot tends to prefer timber which has a dampness level of over 50% whereas dry rot can spread well when moisture levels are only 20%.

Wet Rot is less severe than dry rot as it is usually confined to the area of dampness in timber due to its inability to penetrate masonry whereas dry rot can spread across a much wider variety of surfaces.

What is a Water Table?

A water table is essentially a pond or series of ponds within the geological topography. In London for example, we have 2 water tables. The first being at bedrock level which is potable water and the second being called a perched water table which sits ontop of the London clay basin. These water table levels fluctuate from year to year.

How long do Basement Waterproofing guarantees last?

Typically, Basement waterproofing guarantees last for 10 years providing the waterproofing system has been maintained and serviced in accordance with company and manufacturers instructions. These guarantees can also be underwritten by a third party insurer for that extra peace of mind.

How much does Basement Waterproofing cost?

The cost of Basement waterproofing varies dependent on the type and size of structure that requires waterproofing along with the Type of waterproofing that is required for the structure. Please contact us for further information and we will be able to assist you with your requirements.

How many Basement Waterproofing systems are there?

There are primarily 3 waterproofing systems that can be installed to a below ground structure. We call these Type A, B & C. Each of these, as explained above have certain requirements to ensure the correct design and application. These types can be mixed into a combination system utilising 2 or more systems to achieve the required result.

What is BS8102(2022)?

BS8102(2022) Is a code of practice for structures below ground. Providing guidance and recommendations for protecting this structure against ground water. Any waterproofing system that is designed and installed to a below ground structure, should adhere to BS8102(2022). Further information can be found here

How important is it that the Basement Waterproofing is designed by a competent person?

In a nutshell, Very! Each property is unique in one way or another. It important that the property is correctly assessed and the subsequent waterproofing system is designed in accordance with the construction type and falls in line with BS8102(2022). A surveyor with the accreditation CSSW, (Certified Surveyor in Structural Waterproofing) is qualified and experienced to assess, specify and install the correct waterproofing system based on the structural requirements.

Do I need Basement Waterproofing?

Any structure that is set into the ground surrounded by high ground levels on 1 or more sides is subject to ground water pressure bearing on the structure, if left untreated, this ground water can enter the structure under pressure and cause surface dampness to walls and floors or potential flooding. It is imperative to prevent ground water ingress that a below ground structure is correctly waterproofed.

Need a Survey or Consultation?Basement Waterproofing expertise in London

If you’d like to book a site survey, consultation or no-obligation quotation for our dry & wet rot proofing services in London, please click here or call 0208 959 6424.