Flat Roofing Harrow
Need a flat roof installer or flat roof repair in Harrow? We handle everything from small leaks to full replacements, with clear quotes and tidy workmanship.
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Flat Roofing Services in Harrow
Our Services
About Our Flat Roofing in Harrow
We take flat roofing seriously because most flat roof problems come from rushed prep and sloppy detailing. Our approach is simple, assess properly, explain your options in plain English, then do the job cleanly with materials that suit the roof. If a repair is the right move, we’ll repair it. If it needs replacing, we’ll show you why.
1,000
Project Completed
97%
Customer Satisfaction
40+
Years of Experience
Flat Roof Types We Install in Harrow
Different roofs suit different buildings, budgets, and exposure. Here are the most common flat roofing systems we fit and repair in Harrow.
EPDM Rubber Roofing Harrow
EPDM rubber roofing is a popular choice for flat roofs in Harrow because it’s flexible, tough, and handles movement well. It’s ideal for garages, extensions, and dormers, and it performs well when installed with proper edge trims and secure upstands. If you want a clean finish with reliable waterproofing, EPDM is often a strong option.
GRP Fibreglass Roofing Harrow
GRP fibreglass creates a hard, seamless surface that’s great for roof areas that get regular foot traffic, like balcony-style flat roofs or access routes for maintenance. It gives a neat, modern look, and when the deck and detailing are done correctly, it provides long-term protection with minimal upkeep.
Torch-On Felt Roofing Harrow
Torch-on felt is a proven system for flat roof replacement and repairs in Harrow, especially on larger areas where you need a robust layered build-up. With the right preparation and a quality cap sheet, it delivers strong waterproofing and good value. The key is proper bonding, correct laps, and tidy edges, which is where many roofs fail.
Liquid Roofing Systems Harrow
Liquid roofing is ideal when a roof has lots of awkward details, like skylights, trims, outlets, and parapet walls. The system cures into a single seamless membrane, which helps reduce weak points. We use liquid roofing in Harrow for refurb projects and targeted areas where you want a watertight finish without unnecessary disruption, assuming the roof underneath is sound.
Why Harrow Homeowners Choose Us for Flat Roofing?
Most people just want two things, a roof that does not leak, and a team that turns up, explains it clearly, and leaves the place tidy. We keep communication simple, provide clear quotes, and focus on doing the job properly the first time. No waffle, no pressure, just solid flat roofing work in Harrow.
1,000
Project Completed
97%
Customer Satisfaction
40+
Years of Experience
Trusted Roofing Services Across the
South East
Real feedback matters. Here’s what customers say about our workmanship, reliability, and how we handle the job from start to finish.
Removal of Chimney stack, replacement of roof underlay, guttering and flat roof repair. - Mitchell from Alliance Roofing & Building was the only builder, of many that I had contacted, that climbed a ladder to inspect my flat-roof and to climb into my loft-space to inspect the main roof from the inside. After an extensive review of my property and discussing my options, he emailed me his quotation on the same day. Booking in dates for Alliance & Roofing to commence work was quick and effortless. They arrived on time, completed the work as planned to a professional standard. Provided Photos of work carried out at all stages. I highly recommend Alliance Roofing & Building.
New roof on my bungalow - I recently had the pleasure of working with Alliance Roofing and Building to install a new roof on my bungalow, and I couldn't be more satisfied with the results. From start to finish, the entire process was smooth and professional. Mitchell, who led the project, was exceptional. His expertise and dedication were evident from the moment he arrived. He and his team were not only highly skilled but also incredibly helpful and courteous throughout the entire job. They took the time to answer all my questions
New slate roof - Mitchell and his team installed my new roof and I'm very satisfied. The quality is superb, they were professional, punctual, and communicative. The project finished on time and the site was left spotless.
Guttering repair - Mitchell came to repair my guttering, he was on time, polite, efficient and conscientious. He kept me informed at each stage of the work that was needed.
Roof repairs - Mitchell repointed a chimney and installed a chimney cowl. He also did some cementing work to the roof. Mitchell was very polite and a conscientious worker. He kept me informed throughout the job. Mitchell was able to give me a quote and do the repair work within a few days. I wouldn’t hesitate to recommend Alliance Roofing & Building.
Replacement of flat roof - Mitchell and his team are smart, communicative, skilled, friendly, helpful, trustworthy and reliable. I would highly recommend their roofing services.
Roof tile replacement and chimney repair - Mitchell and his team are reliable, efficient and hard working. We will certainly use them again in the future. Thanks guys
Chimey Removal & Other Minor Repairs - Mitchell was the only roofer who quoted for the job that actually took the time to go up on the roof to inspect the issue, which was appreciated at the time. He fitted us in around other jobs within 2 weeks to get the work done in a timely manner. The work (which included the removal of a chimney stack to below the roof line, repointing the ridge line, and various other patch repairs) appears to have been completed to a good standard (posting days after completion). Mitchell and his team were polite, conscientious and happy to help throughout the job.
Fixed the roof, including all the felting and repaired the chimney. - Good communication throughout. Good work. Very happy with the service.
Roof repair - Great, really friendly and nice team
Tile realignment/repair and felt renewal - Mitchell and his team were excellent. Would definitely recommend Alliance. The team were on time (in fact they were able to begin the job half a day earlier than initially discussed), polite, efficient and kept us informed of progress each day. We could not have asked for a better service.
Roof verge repair. - Mitchell was polite, friendly and knowledgeable. The team were polite and efficient. The work was completed for the price quoted, which was competitive, and in the timeframe advised.
repair of box gutter behind parapet wall - Mitchell undertook a detailed diagnosis of the work required, started the job quite quickly and completed it satisfactorily.
Leak in the roof- Very polite and professional. Job was completed professionally at a very good price. Would highly recommend
New slate roof - Mitchell and his team installed my new roof and I'm very satisfied. The quality is superb, they were professional, punctual, and communicative. The project finished on time and the site was left spotless.
Roof repairs - Mitchell repointed a chimney and installed a chimney cowl. He also did some cementing work to the roof. Mitchell was very polite and a conscientious worker. He kept me informed throughout the job. Mitchell was able to give me a quote and do the repair work within a few days. I wouldn’t hesitate to recommend Alliance Roofing & Building.
Roof tile replacement and chimney repair - Mitchell and his team are reliable, efficient and hard working. We will certainly use them again in the future. Thanks guys
Chimey Removal & Other Minor Repairs - Mitchell was the only roofer who quoted for the job that actually took the time to go up on the roof to inspect the issue, which was appreciated at the time. He fitted us in around other jobs within 2 weeks to get the work done in a timely manner. The work (which included the removal of a chimney stack to below the roof line, repointing the ridge line, and various other patch repairs) appears to have been completed to a good standard (posting days after completion). Mitchell and his team were polite, conscientious and happy to help throughout the job.
Fixed the roof, including all the felting and repaired the chimney. - Good communication throughout. Good work. Very happy with the service.
Roof repair - Great, really friendly and nice team
Tile realignment/repair and felt renewal - Mitchell and his team were excellent. Would definitely recommend Alliance. The team were on time (in fact they were able to begin the job half a day earlier than initially discussed), polite, efficient and kept us informed of progress each day. We could not have asked for a better service.

Every flat roofing job starts with a proper inspection, not guesswork. We check the membrane, edges, outlets, drainage, and any signs of trapped moisture so you get clear, honest advice on whether a repair will hold or if replacement makes more sense.

Once the inspection is done, we provide a clear written quote that explains the work, materials, and timing. No vague pricing, no shifting dates, just a straightforward plan that fits around your schedule.
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All flat roof work is completed carefully, whether it’s a targeted repair or a full replacement. We finish by checking joints, edges, drainage, and waterproofing to make sure the roof is sealed properly before we sign the job off.
Frequently Asked Questions
It depends on the system, the quality of the installation, and how well the roof drains. A well-installed flat roof can last many years, but poor detailing and ponding water will shorten its life quickly. We’ll give you an honest expectation after an inspection.
Common signs include bubbling, splits, lifted edges, water pooling, damp patches on ceilings, or dripping near roof lights and junctions. If you spot any of these, it’s worth getting it checked before water gets into the decking.
If the issue is local and the roof is otherwise in good condition, a repair is usually sensible. If there are multiple leaks, soft areas, or repeated failures, replacement is normally the better long-term call. We’ll tell you which one makes sense for your roof, not what makes us more money.
Yes, in many cases. If the roof build-up allows it, adding insulation during replacement can improve comfort and help with heat loss. We’ll advise what’s practical for your property and the type of roof.
Yes. A lot of our flat roofing work in Harrow is on garage roofs, rear extensions, dormers, porches, and small commercial flat roofs. The approach changes depending on access, drainage, and detailing.
If you have an active leak, we’ll aim to get you booked in as quickly as possible to make it safe and watertight, then follow up with the proper repair or replacement plan.

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