Cellar & below-ground waterproofing
Cellar Tanking Specialists
A damp cellar can quickly become unusable. Whether you are dealing with damp walls, water ingress and musty smells, or planning a cellar conversion, we install cellar tanking systems that keep below-ground spaces dry and protected, designed to BS 8102:2022.
Over 30 Years Experience
Cellar and below-ground waterproofing specialists.
CSSW Qualified Surveyors
Waterproofing assessed and specified to BS 8102:2022.
10-Year Guarantee
Written guarantee on all new waterproofing installations.
CHAS Accredited
Fully insured, fixed-price quotations after survey.
What is Cellar Tanking?
Cellar tanking is a Type A waterproofing method where a cementitious barrier is bonded directly to the walls and floor of a below-ground space, stopping moisture passing through the structure. It is one of the systems set out in BS 8102:2022 for protecting cellars and basements.
The right solution depends on the structure, the condition of the walls and how the space will be used. Tanking suits sound structures and lower-risk cellars; where water pressure is higher, or the cellar is being converted to living space, a cavity drain membrane may be more reliable. Our survey confirms which is right for your property.
Signs You May Need Cellar Tanking
If these problems keep returning, the issue usually needs more than a surface repair. A proper waterproofing system is the most reliable long-term solution.
Cellar Waterproofing for Homes & Commercial Properties
Residential Cellar Tanking
A dry cellar creates useful storage or forms the first stage of a future conversion. We work on period homes, family properties and renovation projects where below-ground moisture needs to be controlled properly.
Commercial Cellar Tanking
We also waterproof commercial buildings, storage areas, service spaces, plant rooms and refurbishment projects that need dependable, long-term cellar waterproofing.
Our Cellar Tanking Process
Survey
We inspect the cellar, identify the cause and extent of moisture, and assess the structure.
Recommendation
We specify the most suitable system to BS 8102:2022 and explain the next steps and fixed price.
Installation
Our team carries out the agreed works with care for the structure and intended use of the cellar.
Dry, Protected Space
You are left with a cellar that is properly protected and reliable for long-term use, with a written guarantee.
Cellar Tanking Costs
Cost depends on the size and condition of the cellar, the system specified and how the space will be used. The ranges below are a realistic starting point; we always survey and provide a fixed-price quote before any work is agreed.
Tanking a small, sound cellar for storage or lower-risk use. Plus VAT.
Larger cellars, or a cavity drain membrane with drainage and sump for conversions. Plus VAT.
All prices are indicative starting points. Your fixed-price quote is provided after a survey, and the survey fee is deducted from the cost of works if you proceed.
Planning a Cellar Conversion?
If you are converting your cellar into a living space, office, gym or utility room, the waterproofing stage needs to be right from the very beginning.
A failed waterproofing system causes major disruption once a space is finished. Getting the correct system in place before finishing works protects the investment and avoids costly problems later. For habitable conversions we usually recommend a Type C cavity drain system.
Why Clients Choose Us for Cellar Tanking
With below-ground waterproofing, success depends on correct diagnosis, the right specification and good workmanship. Clients come to Advanced Damp because we provide:
Accredited & Trusted
Cellar Tanking FAQs
What is cellar tanking?
Cellar tanking is a Type A waterproofing method where a cementitious barrier is bonded to the walls and floor of a below-ground space to stop moisture passing through. It is one of the systems defined in BS 8102:2022 for protecting cellars and basements.
Do I need cellar tanking or damp proofing?
Damp proofing deals with moisture in walls above ground, while cellar tanking protects below-ground spaces against the pressure of groundwater. If your cellar is below ground level, tanking or another structural waterproofing system is the right approach rather than a standard damp proof course. A survey confirms which you need.
How much does cellar tanking cost?
It depends on the size and condition of the cellar and how it will be used. As a guide, tanking a small cellar typically starts from around £3,500, while larger cellars, or those needing a cavity drain membrane and sump for a conversion, typically cost more. We always provide a fixed-price quote after a survey.
Is cellar tanking or a cavity drain membrane better?
Tanking (Type A) resists water with a bonded barrier and suits sound structures and lower-risk cellars. A cavity drain membrane (Type C) manages water to a sump and pump and is often more reliable where water pressure is higher or the cellar will be habitable. We specify whichever suits your property following a survey.
How long does cellar tanking last, and is it guaranteed?
A correctly specified and installed system can last for decades; most failures trace back to poor preparation, the wrong product or water pressure beyond what a barrier system can resist, which is what our survey is designed to rule out. New installations carried out by our team carry a written 10-year guarantee.
Should I tank my cellar before converting it?
Yes. Waterproofing should be designed and installed before any finishing works begin. Getting it right first protects the conversion, whereas retrofitting after a failure is far more disruptive and costly. For habitable conversions we usually recommend a Type C cavity drain system.
Can I tank a cellar myself?
DIY tanking often fails because surface preparation, the correct product and careful detailing around joints and services are critical. A failed system can trap moisture and damage finishes. We recommend a professional survey and installation, which also comes with a written guarantee.
Related Services
Get Your Cellar Surveyed
Book a survey and our CSSW qualified surveyors will diagnose the cause, specify the right system to BS 8102:2022 and give you a fixed price. The survey fee is deducted from the cost of works if you proceed.