Flat Roofing Winchester
Need a flat roof repair or replacement in Winchester? We install and fix felt, GRP and EPDM flat roofs for homes, extensions and garages across SO22 and SO23, with clear quotes and tidy workmanship.
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Flat Roofing Services in Winchester
Our Services
About Our Flat Roofing in Winchester
We focus on doing flat roofs properly, with the right build-up, proper joins, and details that stop problems before they start. Most flat roof failures come from rushed work or weak edges, so we take the time to get the prep and finish right. If you’re in Winchester, SO22, SO23, or nearby villages, we’ll give you a clear plan and a roof that stays watertight.
1,000
Project Completed
97%
Customer Satisfaction
40+
Years of Experience
Flat Roof Types We Install
Different roofs need different systems. We’ll recommend the best option based on the roof shape, how it’s used, and your budget.
EPDM Rubber Roofing
EPDM is a tough rubber membrane that works brilliantly on many flat roofs, especially where you want a clean look and long service life. It handles temperature changes well and is a solid choice for garages, extensions, and outbuildings.
GRP Fibreglass Roofing
GRP creates a seamless finish that’s great for flat roofs where you want a neat, hard-wearing surface. It’s commonly used on extensions, dormers, and balconies. When installed correctly, it’s highly resistant to leaks and cracking.
Torch-On Felt Roofing
Modern torch-on felt is nothing like old-style felt that failed early. Installed in layers with proper detailing, it’s a dependable option that offers strong waterproofing and good value, especially for straightforward flat roof areas.
Liquid Roofing Systems
Liquid systems can be ideal for awkward roof shapes, tricky details, and areas where a membrane is hard to lay neatly. They cure into a waterproof surface that seals around edges and penetrations, which helps reduce weak points.
Why Homeowners in Winchester Choose Us
Because you want it fixed once, not patched forever. We turn up, inspect properly, explain your options in plain English, and quote clearly. We keep the site tidy, respect your home, and focus on workmanship that holds up through Winchester weather, not just on the day the job is done.
1,000
Project Completed
97%
Customer Satisfaction
40+
Years of Experience
Trusted Roofing Services Across the
South East
Recent feedback from local customers who trusted us with flat roof repairs and replacements in Winchester.
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 inspect the roof properly, show you what’s failing, and explain what needs doing now versus what can wait.

You get a clear written quote, a straightforward timeline, and a booking that actually sticks.
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We complete the work carefully, then check drainage, seals, and edges so the roof is watertight before we leave.
Frequently Asked Questions
If the leak keeps returning, the surface is cracked or lifting, or you’ve got widespread soft spots in the decking, it may be time to replace. If it’s localised damage with a solid base, a repair could be enough. We’ll confirm after an inspection.
Pooling usually comes from poor falls, sagging decking, blocked outlets, or previous work that didn’t handle drainage properly. We’ll identify the cause and fix it properly, because pooling shortens the life of any flat roof system.
Many repairs can be completed in a single visit, depending on access and weather. Larger repairs or partial rebuilds can take longer. We’ll tell you the realistic timeline before we start.
Some repairs are possible year-round, but conditions matter. If it’s unsafe or the materials won’t bond correctly, we’ll make the roof safe first and return when the fix can be done properly.
It depends on the roof shape, how it’s used, and your budget. EPDM, GRP, torch-on felt, and liquid systems can all work well when installed correctly. We’ll recommend what suits your extension rather than pushing a one-size-fits-all option.
Yes. We provide a clear quote after assessing the roof, and we’ll explain what’s included so you’re not guessing what you’re paying for.

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