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Basement Waterproofing London

Being below ground, basements and cellars are susceptible to groundwater being forced into the structure under pressure. Factors such as type of structure, depth of the structure, the makeup of surrounding soil and location of the structure all play a part in how much dampness or water ingress is experienced by the basement or cellar during the course of its lifetime. The types and levels of basement waterproofing are just as numerous as the causes of dampness and it is essential that all factors are taken into consideration when designing the waterproofing system.

Type A Waterproofing

Type A basement waterproofing also known as tanking, it is an externally or internally applied barrier system applied to the walls and floors of the structure that can withstand ground water from entering the building under pressure. There are numerous products and methods for applying Type A waterproofing systems including sheet membranes, multi-coat renders, crystalline slurries and bitumen based coatings. A thorough assessment of the structure must be carefully assessed at design stage to ensure its suitability. This system requires the structural elements of the building to be strong enough to withstand ground water pressure.

Type B Waterproofing

Type B waterproofing is an inbuilt characteristic of the actual structure by adding waterproofing additives to the concrete used to form the floors and walls of the structure. Although normally effective in its own right, the joints of the structure are it’s weak spot and as such are susceptible to water penetration. Type B waterproofing is normally backed up by combining type A, C or sometimes both to ensure a watertight system and minimise risk. Type B basement waterproofing is normally specified in newbuild below ground structures.

Type C Waterproofing

Type C waterproofing is essentially a set of dimpled membranes called Cavity Drain Membrane (CDM) installed externally or internally to the walls and floors of the basement structure. A type C basement waterproofing system does not aim to prevent the incoming water to the structure but instead manages it and diverts it into either a pumping chamber or external land drain. This system is suitable for all structure types and is quickly becoming the preferred system for existing cellars and basements that are subject to ground water ingress due to its relatively low risk of defect and ease of installation.

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.