Leak Detection London | Building Leak Investigations

Established in 1986

Pioneers of electronic leak detection in the UK

Over 35,000 successful tests

Excellent Client Reviews

Professional Roof Assessment & Leak Detection Service

Thornton Consulting specialises in investigating and analysing water ingress and leaks in commercial buildings and facilities across London and the surrounding areas. Our professional approach combines precision diagnostics tools with in-depth technical investigations to locate the source of leaks and provide recommendations for repairs to ensure your building remains in excellent condition and maintains its waterproof integrity.

Whether you’re experiencing an ongoing leak at your London office, implementing a forward-thinking maintenance strategy, or seeking rigorous technical documentation for facility management or property assessments, our qualified experts provide exact, trustworthy evaluations designed to meet your particular business needs.

We execute comprehensive surveys, programmed roof inspections, and waterproof integrity testing in London for commercial developments and major residential estates. We take great care to effectively control all possible leak risks, enhance your roof’s performance longevity, and safeguard your significant property investments.

How We Work

  • Planning

    Every project begins with a thorough consultation to understand the nature of your leak concerns, the building's construction and roof build-up, and the extent of any previous remedial work. We take the time to review architectural drawings, waterproofing specifications, and site history to develop a targeted leak detection and testing strategy tailored to your specific needs while minimising disruption to your day-to-day schedule.

  • Testing

    Our experienced technicians deploy innovative, industry-leading electronic leak detection methods tailored to your building's construction. Where exposed, waterproofing membranes are primarily tested using the low voltage (“wet method”) or the holiday/pinhole method where the substrate is conductive. We can also utilise other test methods where the substrate is non-conductive or the membrane is not suitable for traditional electronic leak detection methods, such as differential pressure testing. All testing is conducted methodically to ensure comprehensive coverage and accurate results.

  • Evidence

    Throughout the investigation, we meticulously assess and document every finding with precise location data, digital photography, and detailed notes. Our equipment provides quantifiable measurements that pinpoint leak locations to the centimetre, eliminating speculation or guesswork and ensuring contractors can access the exact areas requiring attention.

  • Recommendations

    Following our analysis, we provide clear, actionable remediation recommendations. Our leak detection reports outline the most appropriate repair strategies, estimated scope of work, and guidance on preventative measures to protect your building's long-term waterproof integrity.

Coverage

Our leak detection specialists provide comprehensive services throughout the City of London and its surrounding boroughs. We work extensively with property managers, facilities teams, and building owners across all areas of the capital.

Central London: EC1, EC2, EC3, EC4, WC1, WC2
West London: W1, W2, W8, W11, SW3, SW5, SW7
East London: E1, E14, E15, E20
North London: N1, N7, N19, NW1, NW3
South London: SE1, SE10, SE16, SW1, SW8, SW11

Key Areas: City of London, Westminster, Camden, Islington, Hackney, Tower Hamlets, Southwark, Lambeth, Wandsworth, Kensington & Chelsea, Hammersmith & Fulham, Canary Wharf, Stratford, King’s Cross

What You Receive

  • Report

    A comprehensive technical document detailing our methodology, findings, and professional assessment will be delivered. Each report will include photographic evidence of findings along with conclusions and recommendations, alongside detailed technical analyses for contractors, building owners, and operational managers to assess.

  • Annotated Plans

    You’ll receive scaled and clear drawings which pinpoint the exact location of every detected breach or area of concern. These annotated plans eliminate any ambiguity and enable accurate quotations from roofing or building contractors.

  • Priorities

    We’ll deliver a clear assessment of which defects require immediate attention and which can be addressed during planned maintenance cycles. This helps you allocate budgets and resources more effectively and manage risk appropriately.

FAQs

How long does a building leak detection survey typically take?

The duration varies depending on the size and complexity of your building, as well as the source of the leak. A typical roof survey can take anywhere from half a day for smaller buildings to several days for large multi-level developments. We always provide an estimated timeframe during our initial consultation and work efficiently to minimise disruption and get you back to your daily routine as quickly as possible.

Can leak detection testing damage our existing roof or waterproofing?

Our electronic leak detection methods are entirely non-destructive and designed specifically to preserve the integrity of your existing waterproofing systems. The test equipment we use will not harm the waterproofing; it purely detects breaches in the membrane which can then be repaired with a suitable product.

What happens if leaks are found during the survey?

If we identify breaches in your waterproofing, we provide you with a detailed report showing exact locations, photographic evidence, and clear recommendations for remedial action. We’ll explain the severity of each defect and advise on priorities. We will provide clear information on the most appropriate solution for repair.

Client Testimonials

I’ve worked with Thornton’s team for nigh on 10 years and I’m yet to be disappointed by any aspect of their business or interaction with any of their staff. I feel that the collaborative approach we have when working together not only benefits our site in a speedy response and solution, but it also strengthens our relationship with our onsite client team, building in faith that together we can self-solve most, if not all issues. Working with Wendy and the onsite teams is nothing short of a pleasure. I would highly recommend using Thornton Consulting Group for all investigative services when it comes to finding leak issues.

OCS Group (Bluewater)

Your team have successfully found the cause of the water ingress. I also wanted to write to express how impressed we are with the professionalism of both Sam and Dave and there health and safety whilst on site. I will be recommending Thornton Consulting going forward to the Hospital and will certainly use this service in the future with Carillion. Many thanks, and also for attending at such short notice.

Carillion Plc

We have worked with Thornton’s for several years now and we could not be happier with the service. The team are really helpful, accommodating and always happy to help us out if we are under pressure from a client. The team are always happy to take a call to discuss a project with them to get a clear understanding of the issues found on site. Thorntons always find the issues and provide a very thorough report to outline them with recommendations on repairs required.

Foxleys Fabrick & Building Maintenance

Thank you for your assistance with the DLI. The contractors used were fantastic and I would definitely recommend using them in the future.

Smart Property Development

Thornton Consulting are extremely professional, reliable and carry out a fantastic service with excellent communication throughout – we would recommend using them and we certainly will be using them again.

Rendall & Rittner

Just wanted to take a moment to commend your team for the works carried out on site. We are really pleased with the results.

TS, M

Thanks for the work carried out and the subsequent report. Sam and Dave were 1st class.

Complete Building Services Ltd

Latest Blog & Case Studies

To find out more about what we do and how we work, read our case studies and blogs below.

Leak Investigations at a Shopping Centre in East Sussex

A shopping centre in East Sussex had been experiencing a series of persistent leaks into one of the retail units. Seven leaks had been reported …

Get in Touch Today

Call us on 01342 410508, email us at mail@thorntonconsulting.co.uk or send us a message using the form below. A friendly member of our team will be in touch shortly.

"*" indicates required fields

Our Accreditations