Services / Flat Roof Repair

    Flat roof repair in London & surrounding counties

    Leaking or damaged flat roof? Rather than patching the same problem twice, we overlay the affected area with Ultraflex, a cold-liquid, fully bonded waterproof layer that bonds to almost any existing surface and is rainproof in 30 minutes.

    • Water coming through the ceiling
    • Leak away from the damage
    • Failed patch repairs
    • Cracked or lifting roof covering
    Instant Estimate
    Common problems

    The problems with traditional flat roof patch repairs

    Standard patch repairs, such as bitumen tape, GRP patches, sealant or felt overlays on a single area, rarely solve the underlying problem. They create new weak points and almost always fail again within a few seasons.

    • New seams and weak points

      Every patch creates a fresh edge bonded onto an aged surface. Those edges lift, crack and leak again as soon as the next winter cycles through.

    • Patches the damp spot, not the leak

      Water often tracks under the membrane far from where it shows inside. Patching the visible damp spot leaves the real failure untouched.

    • Mismatched materials

      Bitumen on EPDM, GRP on felt, sealant on aged membranes. Incompatible materials don't bond properly and peel away under thermal movement.

    • Short lifespan

      Most patch repairs are a 6-24 month fix at best. You pay again and again to chase the same leak around the roof.

    • Hides bigger problems

      Repeated patching can mask saturated insulation and rotting deck below, turning a waterproofing job into a structural one.

    Failed patch repair on a flat roof with peeling, lifted edges and water staining
    Perlini System

    Why patch repairs fail and our waterproofing system doesn't

    Traditional patch repairs often introduce incompatible materials, creating new joints and weak points that can lift, crack, or fail as the roof expands and contracts with seasonal temperature changes. Our waterproofing system bonds seamlessly to the existing substrate, forming a single continuous waterproof membrane. Reinforced with embedded fibreglass matting, it accommodates structural movement while resisting splitting and cracking, providing a durable, long-lasting repair.

    Same roof restored with seamless Ultraflex overlay
    Damaged flat roof with patch repairs and ponding water
    BeforeAfter
    Powered by Ultraflex

    One of the best flat roof waterproofing systems on the market

    Whatever flat roof job you have (installation, repair, replacement, or an asphalt, GRP, EPDM or torch-on felt overlay), we install the Ultraflex cold-liquid waterproofing system. It's the most durable, cost-effective, and reliable flat-roof solution available.

    By overlaying your existing roof with Ultraflex, we save you the cost and disruption of a full strip-out while delivering a fully bonded, seamless waterproof layer backed by a 20-year guarantee. We go in, repair your existing roof and seal it for decades of protection. If needed, we can apply bespoke finishes and solutions post-waterproofing.

    Ultraflex flat roof installation

    Why we install Ultraflex on every job

    Faster installation

    Fast-curing and rainproof in as little as 30 minutes.

    Up to 50% cost savings

    Overlay your existing roof and avoid strip-out costs.

    20-year guarantee

    Proven waterproofing built for long-lasting protection.

    100% Compatible

    Torch-on felt, asphalt, GRP, timber, concrete, and virtually any roof surface.

    Safer installation

    Cold-liquid application, eliminating fire risk.

    Seamless waterproofing

    No joints or laps, just one fully bonded waterproof layer.

    How we work

    1. 1

      Instant Estimate

      Fill out our cost estimate tool to receive a fast, ballpark price based on your project details. It's a quick way to understand likely costs before moving forward.

    2. 2

      Site Visit + Detailed Quote

      We carry out a site visit where needed to assess your roof in detail, then provide a clear, itemised quote with no hidden costs so you know exactly what to expect.

    3. 3

      Installation

      Our trained team prepares the surface and installs the Ultraflex system, delivering a seamless, fully bonded waterproof finish built to last.

    4. 4

      Sign-off & 20 Year Guarantee

      We inspect the roof, hand over your 20-year guarantee documentation, and leave the property spotless.

    Useful guides

    How Ultraflex compares

    See how our Ultraflex cold-liquid waterproofing system stacks up against traditional flat roof systems across the things that matter most.

    CriteriaUltraflexGRPEPDMAsphaltFelt
    Seamless, fully bonded
    Yes
    Yes
    No
    No
    No
    Cold-applied (no flame)
    Yes
    Yes
    Yes
    No
    No
    Rainproof in 30 minutes
    Yes
    No
    No
    No
    No
    Overlay existing roof
    Yes
    No
    No
    No
    Yes
    20-year guarantee
    Yes
    Yes
    Yes
    No
    Yes
    Cost-effective long-term
    Yes
    No
    Yes
    No
    No
    Resists cracking & shrinking
    Yes
    No
    Yes
    No
    No
    Suitable for complex detailing
    Yes
    Yes
    No
    No
    No

    Ultraflex repairs are typically up to 50% cheaper than a full strip-out because we overlay rather than rip up your existing roof. Use our estimator for a quick indication.

    Ultraflex FAQs

    The most common questions we get asked about the Ultraflex cold-liquid waterproofing system.

    For active leaks into an occupied building we prioritise attendance and can usually carry out a temporary weatherproofing visit quickly to stop water getting in, then schedule the permanent repair once the roof has been properly surveyed and dried.

    Because water travels. It enters at a defect, runs across the deck or through the insulation, and drops through at the first joist, penetration or change of level it meets. This is why repairing the spot directly above the ceiling stain so often achieves nothing, and why we survey the whole roof before quoting.

    It depends on the condition of the insulation and deck rather than the age of the covering. If the build-up is dry and the failure is localised, an overlay repair is excellent value. If water has saturated the insulation across a wide area or the deck has begun to rot, cutting out and rebuilding those areas is the only honest answer, and we will tell you which situation you are in.

    A properly diagnosed overlay repair using the reinforced liquid system carries the same twenty-year guarantee as a full roof. Tape, sealant and patch repairs, by contrast, typically hold for six to twenty four months, because they create a new stressed edge without removing the cause of the original failure.

    Yes. The resins are formulated for application down to around freezing on the main roof and slightly below on details, and they are rainproof in as little as thirty minutes, so repairs are practical through the months when flat roof leaks actually show up.

    Regularly. Most of our repair work is on felt, asphalt, GRP, EPDM and single ply roofs installed by others, including roofs that have already had several unsuccessful patch repairs. The system bonds to all of those substrates once they are prepared and primed correctly.

    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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