Flat Roof Surveys
Independent, professional flat roof surveys across London and England. From quick visual inspections to in-depth invasive surveys and pinpoint leak detection - we'll tell you exactly what's going on with your roof and what to do about it.
Know exactly what you're dealing with
Flat roof problems are easy to misdiagnose. A patch in the wrong place, an insulation issue missed, or a leak source tracked to the wrong area can cost thousands and still leave you with the same problem six months later.
Our surveys give you an independent, written record of your roof's true condition - backed by photos, thermal imaging and (when needed) core samples - so you can make the right decision the first time.
Three survey types - one for every situation
Not sure which you need? Just request a quote and tell us what you're seeing - we'll recommend the right approach.
Non-Invasive Survey
Visual inspection with thermal imaging
A full visual inspection of your roof, flashings, upstands and outlets - supported by thermal imaging and moisture meter readings where useful. Ideal for routine condition reports, pre-purchase checks and insurance claims, with no disruption to your building.
- Full visual inspection of roof, flashings & details
- Thermal imaging to spot trapped moisture
- Moisture meter readings on suspect areas
- Written report with photos & recommendations
Invasive Survey
Core samples & build-up analysis
When you need certainty about what's beneath the surface, we take small core samples to confirm the existing roof build-up, insulation condition and substrate integrity. Used to specify refurbishment works, confirm structural loading and resolve disputes with confidence.
- Core samples to confirm roof build-up
- Insulation & substrate condition assessed
- Detailed build-up drawings supplied
- Reinstatement included so the roof stays watertight
Leak Detection Survey
Pinpoint the source - fast
Flat roof leaks rarely show up where the water comes in. Using electronic leak detection (ELD) and flood testing where required, we pinpoint the exact source of water ingress so it can be fixed properly - first time.
- Electronic Leak Detection (ELD)
- Flood testing on suspect areas
- Dye testing for complex / hidden leaks
- Thermal imaging to spot trapped moisture
- Clear report identifying the source & fix
What to expect from your survey report
Every survey is delivered as a clear, jargon-free written report - designed to help you understand exactly what's going on and what to do next.

On-site inspection
A qualified surveyor inspects every detail of your roof - membrane, flashings, upstands, outlets and rooflights - documenting findings with high-resolution photos.

Diagnostics & imaging
Thermal imaging, moisture readings and (where needed) core samples give us hard evidence - not guesswork - about the true condition beneath the surface.

Digital report & next steps
You'll receive a clear PDF report covering condition ratings, annotated photos, identified defects, recommended remedial works and indicative costs.
View example surveyWhat clients say
"From the initial inspection through to completion, the team was professional, knowledgeable, and reliable. The workmanship was completed to a very high standard, with great attention to detail. The site was kept tidy, the team arrived when they said they would, and the project was completed on schedule. It's refreshing to find a contractor who takes such pride in their work and genuinely cares about customer satisfaction. I would have no hesitation in recommending Perlini Flat Roofing to anyone"
Darren Okosi
Senior Property Manager
"Perlini responded quickly, identified the issue efficiently, and carried out the repair to a high standard. Everything was clearly explained, which gave me confidence throughout. They were punctual, tidy, and respectful of the property, leaving everything clean once the job was completed. Reliable, skilled, and easy to deal with, I would not hesitate to use them again or recommend them to others."
Frankie Abbott
"Perlini are by far the best contractors I have worked with. I am always confident they will find a solution to even the most difficult problems and their work is always to an exceptional standard."
Dominic Chan
"Excellent communication and highest level of professionalism as they have not only resolved long standing issues but present reports in a timely manor and support with client/manager relations. Will continue to use."
Karl Bradley
"Excellent service all the way through including communication. The completed work was great! Very efficient and cleaned up brilliantly afterwards too. First-class service!"
Lewis Portar
"Perlini Flat Roofing recently installed an Ultraflex waterproofing system on our flat roof and did an excellent job. The team were professional, knowledgeable, and kept us informed throughout the project. The workmanship was first-class, the site was left clean and tidy, and the finished roof looks fantastic. I would highly recommend Perlini Flat Roofing to anyone looking for a reliable contractor and a high-quality Ultraflex installation."
James H.
"We chose Perlini Flat Roofing to install an Ultraflex system after experiencing ongoing leaks. From the initial survey to completion, the service was excellent. The team clearly knew their trade, arrived on time, and carried out the work to a very high standard. The roof is now completely watertight and comes with real peace of mind as Ultraflex provide a 20 year warranty."
Sarah M.
What a professional flat roof survey involves
A survey is not a quick look from a ladder. We access the roof properly, walk the whole surface, and record its condition area by area rather than only inspecting where a leak has shown up inside. That distinction matters, because water rarely enters a flat roof directly above the stain on the ceiling: it travels along the deck or through the insulation until it meets a joist, a service penetration or a change of level, and drops through there. Surveying only the visible symptom is how the same leak gets paid for three times.
We inspect every part of the build-up that can fail. That means the open field of the roof, every lap, weld or seam, the upstands and how they terminate, the edge trims and parapet copings and their joints, all rainwater outlets and gutters, and each pipe, kerb, rooflight and plant plinth. We check the falls and whether water actually reaches the outlets, look for ponding marks, blistering, splitting, shrinkage and previous patch repairs, and where the underside of the deck is accessible we inspect that too for staining, soft boards and corroded fixings.
Moisture readings and thermal imaging
The most important question on any ageing flat roof is whether water has already reached the insulation. Moisture readings and, where useful, thermal imaging let us map how far water has spread beneath the covering. A roof that looks tired but is dry underneath is an excellent candidate for a straightforward overlay. A roof with saturated insulation across a wide area needs those boards cut out and replaced before any new waterproofing goes on, and knowing which situation you are in before you commit money is the whole point of commissioning a survey.
Digital report and next steps
You receive a written digital report with annotated photographs of every defect we found, an explanation of what is causing each one, an assessment of the remaining service life of the covering, and clear recommendations ranked by urgency. Where remedial work is needed the report is accompanied by an itemised quotation, so you can see exactly what each element costs rather than being handed a single figure. The report is yours to keep and to share with a managing agent, an insurer, a surveyor or a prospective buyer.
When a survey is worth commissioning
The obvious trigger is an active leak, particularly one that has already been patched unsuccessfully. But surveys are just as valuable before buying a property with a flat roof of unknown age, when a managing agent needs condition evidence for a service charge or a planned maintenance programme, before installing solar panels or rooftop plant that will add load and foot traffic, when preparing an insurance or warranty claim, or simply on a roof approaching the end of its expected life where you would rather plan the replacement than be forced into it by a winter storm.
We survey felt, mastic asphalt, GRP fibreglass, EPDM rubber, single ply and liquid-applied roofs, on domestic extensions and garages through to hospital, school and high-rise commercial buildings across London and the Home Counties. If the survey shows the roof has years of life left in it, we will tell you that and recommend maintenance rather than selling you a new roof you do not yet need.
Flat roof survey — frequently asked questions
What to expect when you commission a condition survey on a flat roof, and how we report back.
How much does a flat roof survey cost?
The fee depends on the size and accessibility of the roof and on whether you need moisture mapping and thermal imaging as well as a visual condition survey. We confirm the figure before booking, and where the survey leads to remedial work with us the cost is normally credited against it.
How long does the survey take and when do I get the report?
Most domestic roofs take one to two hours on site; larger commercial roofs take longer and may need phased access. The written digital report, with annotated photographs and an itemised quotation for any recommended work, follows within a few working days.
Do you need access inside the property?
Ideally, yes. Seeing the underside of the deck and any internal damp staining tells us a great deal about how long a defect has been running and whether the problem is structural as well as a waterproofing failure. If internal access is not possible we still survey the roof itself and say so in the report.
Can you tell whether the insulation is wet?
Yes, that is one of the main reasons to commission a survey. Moisture readings, and thermal imaging where it is useful, map how far water has spread through the build-up. This decides whether the roof can simply be overlaid or whether saturated boards need cutting out and replacing first.
Is the survey report suitable for an insurance or warranty claim?
It is written to be used that way. The report sets out what we found, photographic evidence of each defect, our assessment of the cause, and our recommendations, which is the evidence insurers, managing agents and surveyors normally ask for.
Will you just tell me I need a new roof?
No. Plenty of the roofs we survey have years of life left and need nothing more than clearing the outlets and attending to two or three details. Where that is the case the report says so and recommends maintenance. We would rather give you an honest assessment than sell work you do not need.
Do you survey roofs installed by other contractors?
Almost all of them are. We survey felt, mastic asphalt, GRP fibreglass, EPDM rubber, single ply and liquid-applied roofs regardless of who installed them, including roofs that have already had several unsuccessful patch repairs.
Services tailored to your flat roof, we work on any job.
From new installations and full system refurbishments to targeted leak diagnostics and repairs, every project is carried out by our in-house specialists using premium, manufacturer-approved liquid waterproofing systems.
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