Damp patches & tide marks
Dark staining or rising tide lines on walls and floors show moisture is getting into the structure.
London & Home Counties BS 8102 specialists
Basement Waterproofing in London
Stop damp, leaks and water ingress for good. Our CSSW-qualified surveyors find the cause, design the right BS 8102 system, and our Delta-approved technicians install it, fully guaranteed.
- 50+ years’ experience
- Delta approved installers
- Fully guaranteed waterproofing
- 1000s of London projects completed
We respond within one working day
Request a Callback
Speak to a waterproofing specialist about your basement. No obligation, just expert advice.
Prefer to talk now? 020 3795 4900
- 50+Years of waterproofing experience
- 1000sProjects completed across London
- BS 8102Compliant waterproofing design
- CSSWQualified waterproofing surveyors
Approved systems we install
Delta®
KÖSTER
Sika®
Common warning signs
Is water getting into your basement?
Below-ground rooms in London are under constant pressure from groundwater, heavy clay soils and ageing Victorian masonry. If you notice any of these signs, it is time for a professional survey.
Water ingress after rain
Puddles, trickles or seepage at wall and floor junctions point to water pressure from the surrounding ground.
Musty smells & mould
Persistent odours and mould growth affect air quality, health and anything you store below ground.
White salt deposits
Efflorescence, a powdery white residue, shows water is moving through the brickwork and evaporating.
Blown plaster & peeling paint
Failing finishes and crumbling render are often caused by moisture trapped behind the surface.
Failed tanking or old systems
Cracked tanking, failed membranes or a struggling sump pump need expert assessment before they get worse.
Installation
Completed
Specialist waterproofing
Basement waterproofing with guaranteed results
Universal Basement Waterproofing is part of Universal Home Build (opens in a new tab). We strip properties back to the substrate and install a proven waterproofing system, including the Delta membrane system, for which we are an approved installer. Then we fully refurbish the space, with every specialist trade the project needs.
Our service runs from survey to finished room for projects from £10,000 to over £1 million. It is backed by documented testing results, on-site technical support, a comprehensive survey report and a Universal guarantee on all our work.
Our technicians will
Qualified in Delta, KÖSTER and Sika systems
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Survey your basement A full survey, with time to discuss your project requirements.
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Find the cause Identify exactly where and why water is getting in.
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Recommend the right system A waterproofing system tailored to your needs and budget.
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Specify proven products The right waterproofing products for your project.
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Leave it dry & ready Your basement left in a dry, safe state, ready for use.
BS 8102:2022 waterproofing systems
The three types of basement waterproofing
British Standard BS 8102:2022 defines three types of waterproofing protection. After investigating ground conditions, drainage, future risks and the construction method, our surveyors design a value-engineered scheme using Type A, B or C, or a combination for maximum security.
View larger diagram (opens in a new tab)
System components
- Waterproofing layer
- Wall
- Concrete floor
- Loading coat
Type A
Barrier protection
Protection against water ingress by a separate barrier system, applied internally, externally or sandwiched within the structure.
Typically used for: Cementitious tanking and applied barrier coatings, well suited to many cellar and vault conversions.
View larger diagram (opens in a new tab)
System components
- Water-resistant reinforced wall and slab
- Waterstop, internal or external as required
- Waterstop at the wall and slab junction and all joints
- Piled wall may require facing
- Concrete or steel piled wall
- Waterstop following the wall profile at the junction
- Water-resistant concrete floor or slab with added barrier
Type B
Structurally integral protection
Protection against water ingress which is provided by the structure itself.
Typically used for: Water-resistant concrete and admixtures such as Sika®-1, ideal for new-build basements.
View larger diagram (opens in a new tab)
System components
- Inner skin
- Cavity drain membrane
- Pump
- Drainage channel connected to discharge point
- Sump
- Wall cavity
- Internal block wall
- Access point to drainage
- Reinforced concrete or steel pile wall
- Waterstop at the junction, following the wall profile
- Drainage channel
Type C
Drained protection
Protection against water ingress into usable spaces is provided by an internal water management system.
Typically used for: Delta cavity drain membranes with drainage channels, sumps and pumps, widely specified for habitable basements.
Pumps are an essential part of a Type C system. We provide contact details for PPS (Packaged Pump Systems), who maintain and service every pump we install.
Systems can be combined
- A + B
- A + C
- B + C
Although Type B structures are designed to be water resistant, additional waterproofing may be applied internally or externally to control water vapour movement where appropriate.
Expert detail: steels below ground
Where structural steels or lintels sit in earth-retaining walls in a Type C design, we specify a bespoke polymeric joist boot. It fully isolates the steel ends from the retaining wall, so they can be detailed into the cavity drain membrane to the manufacturer’s recommendations.
More about waterproofing systemsHow it works
From first call to a dry, usable basement
A clear, four-step process with expert guidance at every stage.
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1
Book your survey
Call us or complete the form. We will discuss your basement and arrange a convenient visit.
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2
Site investigation
A qualified surveyor identifies the cause of water ingress and assesses ground conditions, drainage and future risks.
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3
Design & quotation
You receive a detailed report, a BS 8102-compliant design and a clear, no-obligation quotation.
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4
Install, test & guarantee
Our technicians install, test and document the system, then hand over a dry space that is fully guaranteed.
Our work
Recent basement waterproofing projects
From Victorian cellars to luxury lower-ground living spaces, see how we have protected properties across London.
Hampstead
Hampstead Basement Waterproofing Project
Hampstead basement waterproofing case study covering hillside Victorian basement damp remediation, Type C cavity drain systems, sump pump redundancy & BS8102 structural…
Read case study (opens in a new tab) IslingtonIslington Basement Waterproofing Project
Expert Islington basement waterproofing case study for Victorian properties. Structural waterproofing, damp remediation, cavity drain systems & BS8102 compliance.
Read case study (opens in a new tab) WestminsterWestminster Basement Waterproofing Project
Westminster basement waterproofing case study covering Victorian basement damp remediation, Type C cavity drain systems, sump pump redundancy & BS8102-compliant structural protection.
Read case study (opens in a new tab)Why Universal
Why London homeowners choose us
50+ years’ experience
Five decades designing and installing waterproofing for homes and commercial properties across London and the Home Counties.
CSSW-qualified surveyors
Certified Surveyors in Structural Waterproofing diagnose the real cause and specify the right system.
Manufacturer-approved systems
Delta approved installers, trained in Delta, KÖSTER and Sika products to precise manufacturers’ standards.
One-stop solution
We waterproof the space and then fully refurbish it, with every specialist trade provided by one team.
Documented & tested
Full documentation of testing results, on-site technical support and a comprehensive survey report.
Fully guaranteed
Every installation is backed by a Universal guarantee, so your basement stays dry for years to come.
Areas we cover
Basement waterproofing across London & the Home Counties
We cover all of London and the Home Counties, including Kent, Surrey, Essex and Sussex, with offices in London, Sevenoaks and Kent.
FAQs
Basement waterproofing questions, answered
Straight answers to the questions homeowners ask us most. For advice on your own property, speak to our team.
Still have a question?
Our waterproofing specialists are happy to help.
Call 020 3795 4900 info@unbw.co.ukHow much does basement waterproofing cost?
The cost depends on the size of the basement, the ground conditions, how you intend to use the space and the waterproofing system required. Our projects range from around £10,000 to over £1 million. Every property is different, so we recommend a professional survey, after which you receive a detailed, no-obligation quotation tailored to your requirements.
Do I need planning permission for a basement?
In many cases, basement waterproofing alone does not require planning permission. However, basement construction, excavation or significant structural alterations may require planning approval and Building Regulations compliance, particularly in certain London boroughs or conservation areas. We can advise you during your survey.
How long does basement waterproofing take?
It depends on the size and complexity of the work. Smaller waterproofing installations can often be completed within a few days, while larger basement construction or full structural waterproofing projects may take several weeks. Following your survey, we provide a clear project schedule so you know exactly what to expect.
What waterproofing system do you recommend?
No single system suits every property. The right solution depends on the construction of the building, ground conditions, water ingress risk and how you intend to use the basement. Our surveyors recommend the most appropriate BS 8102-compliant system, whether that is Type A (barrier protection), Type C (cavity drain membrane) or a combined system for maximum protection, using proven products from Delta, KÖSTER and Sika.
Do you guarantee your waterproofing work?
Yes. We install high-quality waterproofing systems from leading manufacturers such as Delta, KÖSTER and Sika, following BS 8102 standards for below-ground waterproofing. Our systems are fully guaranteed, and we explain the guarantees available during your survey.
What areas do you cover?
We provide basement waterproofing and construction services throughout London and the Home Counties, including Kent, Surrey, Essex and Sussex. If you are unsure whether we cover your location, get in touch and our team will be happy to help.
Can you waterproof an existing basement?
Yes. We regularly waterproof existing basements, cellars and vaults, whether they are affected by damp and water ingress or you are planning to convert the space into a dry, usable room. We carry out a professional survey to identify the cause of the problem before recommending the most suitable solution, designed to comply with BS 8102.
Why should I choose Universal Basement Waterproofing?
With over 50 years of experience, we have designed and installed waterproofing systems for properties across London and the Home Counties. Our surveyors design BS 8102-compliant solutions using trusted systems from Delta, KÖSTER and Sika, and we deliver long-lasting, fully guaranteed results from survey through to installation.
How soon can you carry out a survey?
We aim to arrange surveys as quickly as possible, subject to availability. One of our waterproofing specialists will assess your basement, discuss your requirements, identify any damp or water ingress and recommend the most suitable solution. You then receive a detailed, no-obligation quotation.
Get started
Book your basement waterproofing survey
Tell us about your property and one of our specialists will be in touch to arrange your survey and discuss the best waterproofing solution.
Your survey includes
- Detailed site investigation
- Water-ingress diagnosis
- Type A, B and C system assessment
- Written report and no-obligation quotation
Request Your Survey & Quote
Share a few details and we will arrange your survey.