Basement Waterproofing
Due to the clay base of the Thames Valley Basin, basement tanking in London is a very common treatment to waterproof below-ground living space. Older Victorian terraced houses usually have a basement and damp is a very real threat, regardless of the style and size of a cellar. These basements are often used as a studio flat, while they can also be used as a storage space. If damp is present, this is a health hazard, as mould typically grows in still and humid spaces. Black mould is extremely dangerous and prolonged exposure can lead to serious respiratory issues. If you notice any signs of mould, we advise you not to use the space and contact us as soon as possible.
There are several ways to waterproof a basement, which we outline below.
Basement Tanking
There are two main basement waterproofing treatments, basement tanking, which involves removing all damp plaster from the walls and ceilings, preparing the substrate and applying a waterproof render with several coats. The walls are then given a skim of plaster and the basement is ready for occupation. It is important to generate a positive airflow inside an underground living space, which can be achieved with a series of extractor fans. This is the preferred solution if the moisture is minimal and when we recommend a basement tanking contractor.
Cavity Drainage System
The other method of basement waterproofing is to install a cavity membrane drainage system, which keeps the internal walls, ceilings and floors isolated and dry; water runs down into channels under the floor and is then pumped to drainage points. Studded membrane sheets are fitted to the walls, creating a channel in which water can run down into a sump channel in the floor, which is then pumped to designated drainage points. Prior to the work commencing, everything must be removed from the basement, then the walls must be prepared. A large basement might take up to a week to waterproof, as the ceilings, walls and floors must be prepared for the studding to be fitted. Once the studded membrane is in place, waterproof plaster is applied and when the first coat is completely dry, a second coat is applied and finally a skim of plaster leaves a smooth finish. Once a cavity drainage system has been installed and the basement is dry, you can occupy the space.
Why London Basements Need Waterproofing
The high water table and the usual heavy rainfall create a damp environment and that is bad news for those with underground living space; many homeowners only use the cellar for storage due to the damp and humid air. In particular, older terraced houses are prone to damp, as the damp proof course used many decades ago can easily become compromised, not to mention water penetrating the walls. Moisture seeps through brickwork and damages plaster, where mould can form and a stale odour fills the space, making it unsafe for occupation. If you wish to use the basement for living space, it is essential that the structure is free from damp, mould and timber rot. If you are unsure about your basement, contact us and arrange for one of our PCA-certified surveyors to assess your basement and we can recommend the best solution.
Discuss the Situation with Our Damp Surveyor
While we provide professional damp inspections, we do not carry out basement tanking, however, we do work closely with London’s best basement tanking contractor and our surveyor is happy to discuss the options and give you his professional opinion. If damp reappears, they will fix it at no cost to you, regardless of the reason. This gives our customers peace of mind, knowing that their basement has been professionally waterproofed, using the very best materials and a high level of workmanship.
Give London Damp Specialists a call on 020 8528 3277 or complete the booking form on this site and one of our PCA certified damp surveyors will arrange a date and time to carry out the inspection and you will receive a detailed report the following day.
Customer Testimonials
There are two main methods used to damp-proof a basement; the first is called basement tanking, which involves removing all damaged plaster, preparing the substrate and applying a waterproof plaster, with several coats applied after each has thoroughly dried. The second method is called a cavity drainage system that entails fitting a studded membrane on ceilings and walls to create a cavity and water runs down to channels in the floor, where is is pumped from a sump area to designated drainage points. The latter is used when there is a high level of moisture and when done correctly, it keeps the interior dry at all times.
The short answer is yes. If you book a damp survey, our PCA-certified surveyor carries out a thorough inspection and sends you a detailed report that includes recommended waterproofing treatment. We work closely with one of the best damp-proofing companies in London and they guarantee their work for a full 30 years. There are several ways to waterproof a basement and our qualified surveyor will recommend the best treatment.
If the customer requests that we only inspect the basement, we can obviously comply with the request, however, moisture could be present due to issues in other parts of the building. If our surveyor feels that they should inspect other areas of the property, this is what they would request. If you have recently had the building surveyed for damp and nothing was found, this is enough evidence to show that only the basement should be inspected. We are always customer-focused and will do what we can to offer the best services we can.
If a property has damp issues, time is of the essence, as moisture causes damage as soon as it comes in contact with materials. From a convenience standpoint, the summer is an ideal time to carry out damp-proofing work, yet such work can be done at any time of the year. Most homeowners wish to go ahead with remedial work as soon as it can be arranged and we work closely with the best damp-proofing contractor in London and they are always happy to schedule work as soon as possible. Our surveyors are happy to work weekends if it is not possible to survey on a regular day, we are prepared to fit in with the customer’s schedule.
Our initial recommendation would be to make contact with the company that carried out the work and request that they make good. However, if this is not possible for any reason, we would be happy to inspect the property and make recommendations for remedial work. The best solution is to book a damp survey via our website or call us on 0207 205 4886 and we can arrange for one of our PCA-certified surveyors to inspect the property. While we do not carry out damp-proofing work, we do work closely with a top damp-proofing London company that issues a full 30-year warranty on all work.
At London Damp Specialists, we do not carry out damp-proofing work, we only do damp surveys, however, we work closely with a top damp-proofing company and they issue a full 30-year guarantee on all work. If, for any reason, an area that has been damp-proofed requires work, the company will carry out the work free of charge.
At London Damp Specialists, we only offer damp surveys, however, we do work closely with one of London’s leading damp-proofing contractors and they can schedule the work as quickly as you like. Typically, within one week of survey completion, or sooner if possible.
Damp Survey Costs
Transparent pricing with no hidden fees for our independent, unbiased surveys.
Level 1
What’s included:
- Inspection of walls
- Inspection of floors
- Inspection of ceilings
- Leak inspection of drains and plumbing
- Damp information and prevention guide
Level 2
What’s included:
- Everything in Level 1
- Dry rot inspection
- Wet rot inspection
- Woodworm inspection
- Damp information and prevention guide
Level 3 (Most Popular)
What’s included:
- Thermal Imaging
- Air humidity testing
- HD boroscope camera
- Brickwork pointing inspection
- DPC inspection
- Ventilation flow test on extractor fans
- 4K drone imagery roof, chimney stack
and guttering inspection - Structural condition inspection
- Inspection of walls
- Inspection of floors
- Inspection of ceilings
- Leak inspection of drains and plumbing
- Dry rot inspection
- Wet rot inspection
- Woodworm inspection
- Damp information and prevention guide
Survey Add Ons
Add On 1
Laboratory analysis Of plaster identifies hygroscopic salts such as chlorides and nitrates. which indicate whether damp is caused by rising groundwater or by plumbing leaks, This testing removes guesswork, allowing the exact source of moisture to be identified so the correct treatment is applied rather than carrying out unnecessary damp-proofing work.
Add On 2
qPCR DNA mould testing detects microscopic mould spores that are invisible during a normal inspection and van remain hidden behind walls, floors. or inside building rkaterials. It identifies the exact mould species present and the contamination level, allowing hidden mould problems to be confirrned and properly treated before they affect the property or occupants’ health.
Qualifications: All our surveyors are PCA and CSRT qualified for remedial treatments and also CSSW qualified for structural waterproofing.
Next day report: You will receive the report within 24 hours of the inspection taking place.
These are the tools we use
Damp Meter
A damp meter is a diagnostic tool used to detect and measure moisture levels within building materials such as plaster, brick, timber, and concrete.
Borescope camera
borescope camera is a small inspection camera attached to a flexible semi-rigid cable that allows you to see inside areas that are otherwise inaccessible.
Drone Inspection
A drone is a remotely operated aerial device equipped with a camera that allows visual inspection from above without the need for scaffolding or ladder.
Air Humidity Sensor
Air humidity sensor measures the amount of moisture present in the air, expressed as relative humidity (RH) in percentage. It helps determine whether indoor conditions are contributing to condensation, mould growth, or damp-related issues.
Thermal Imaging Camera
A thermal imaging camera detects temperature differences on surfaces by using infrared technology to produce a heat map image. In damp investigations, it helps identify cold spots, moisture intrusion, insulation defects, thermal bridging and leaks.
Air Flow Ventilation Detector
An air flow ventilation detector measures the movement and volume of air passing through vents, extractor fans, and air bricks. It confirms whether ventilation systems are working properly and achieving adequate air changes within a room. Poor airflow leads to trapped moisture, high humidity, condensation on cold surfaces, and ultimately mould growth.
Mould Lab Swab Testing
A mould swab test is carried out to confirm the presence of hidden mould growth and identify the specific species involved. Surface mould is not always visible, especially behind furniture, inside cavities, or within ventilation systems. Laboratory analysis of a swab sample determines whether active mould spores are present and what type they are, which helps assess potential health risks and decide the correct remediation approach rather than relying on visual assumption alone.
Lab Analysis of Plaster
Laboratory analysis of plaster is used to identify the type of salts present within the material, typically chlorides and nitrates. The presence and concentration of these salts help determine whether the moisture source is consistent with rising damp, ground contamination, or another forms [sic] of water ingress. such as mains water leak, This removes guesswork and prevents misdiagnosis, ensuring the correct remedial treatment is specified rather than applying unnecessary or ineffective solutions.
Contact Us
If you have some questions, please complete this form:
Book and Pay for a survey
If you are ready to book a survey and pay, please complete this form:
