Flat Roofing Streatham
Flat roof installation, replacement and flat roof repairs in Streatham, SW16, for extensions, garages, dormers and residential properties across South London.
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Flat Roofing Services in Streatham
Our Services
About Our Flat Roofing
Flat roofs are common across Streatham, especially on rear extensions, dormers and garages. The difference between a flat roof that lasts and one that fails early comes down to preparation, drainage and correct detailing around edges and penetrations. We focus on the fundamentals, then finish cleanly so the roof performs properly and looks right on the property.
1,000
Project Completed
97%
Customer Satisfaction
40+
Years of Experience
Flat Roofing Systems We Offer
We offer several flat roofing systems so you get the right fit for your roof layout, budget and expected lifespan.
EPDM Rubber Roofing
EPDM rubber roofing is a strong option for larger flat roof areas because it stays flexible and resists cracking. It works well for Streatham extensions and garages where you want a long-lasting, low-maintenance roof with excellent waterproof performance.
GRP Fibreglass Roofing
GRP fibreglass roofing creates a seamless finish that’s ideal for smaller flat roofs and areas where clean detailing matters. It’s a popular choice for dormers, porches and compact extensions where you want a neat, durable surface.
Torch-On Felt Roofing
Torch-on felt is still a solid choice when installed properly. We use multi-layer systems and focus on the common failure points, like edges, corners and outlets, to avoid the peeling and splitting that comes from rushed work.
Liquid Roofing Systems
Liquid roofing systems are ideal for awkward roof shapes and detailed areas where sheet materials can struggle. Applied as a seamless coating, they can be effective for overlays and complex junctions, creating a watertight finish without weak joins.
Why Streatham Homeowners Choose Us?
You don’t want a roofer who guesses, you want someone who explains what’s wrong and fixes it properly. Streatham homeowners choose us for straight advice, tidy work, and repairs that actually last. We turn up when we say we will, keep you updated, and leave your property clean when the job’s done.
1,000
Project Completed
97%
Customer Satisfaction
40+
Years of Experience
Trusted Roofing Services Across the
South East
We’re proud of the feedback we get, because most of it comes down to the same things, clear communication, clean workmanship, and no mess left behind.
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.

We start with a proper look at the flat roof, including edges, joints and drainage points, then explain what’s causing the issue and what the realistic options are.

You get a clear written quote with a sensible timeframe. If the roof needs urgent attention, we’ll prioritise it and book you in as quickly as possible.
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Once the work is complete, we check the details that usually get missed, outlets, seams, edges and flashings, then run through aftercare so you know what to look out for.
Frequently Asked Questions
If the leak is localised and the membrane is still in decent condition, repairs often work well. If there are multiple leaks, widespread cracking, lifting edges or soft decking, replacement is usually the safer option.
It depends on the roof. EPDM suits larger areas, GRP works well on smaller roofs, felt can be cost-effective, and liquid systems help with complex shapes. We recommend the best option after inspecting your roof.
Many garage and extension flat roofs are completed in one to two days. Larger roofs or those needing decking and insulation changes can take longer.
Yes. If the deck is soft, damaged or holds moisture, it needs to be repaired or replaced. Installing over a bad deck is how roofs fail early.
Can you fix a flat roof leak quickly?
Yes. We provide free quotes and clear advice, so you can make a decision without pressure.

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