At KC BUILT, we are an approved contractor for Proteus liquid-applied roofing systems, one of the few manufacturer accreditations in the UK that genuinely changes what a client receives at handover. A Proteus-approved installation is not a marketing label. It is a documented chain of training, on-site supervision and post-completion inspection that allows the manufacturer to back the roof with a full system warranty, often of 20 to 25 years.
For commercial property owners, landlords and tender-led developers, this matters more than most realise. The difference between a generic liquid waterproofing job and a certified Proteus system is the difference between an insurance-grade roof and a five-year patch.
What "approved contractor" actually means
Proteus does not approve businesses. They approve installers. Every operative we send to site has been individually trained on the specific Proteus Pro-System, Cold Melt or Deck membrane being installed. We submit method statements before works begin, the manufacturer signs off on the substrate condition, and a Proteus technical representative visits during application to verify thickness, lap detailing and primer compatibility.
The result is a single point of accountability. If anything fails within the warranty period, the manufacturer is contractually obliged to remediate, not the installer, not the developer. For a tender package or a client managing a portfolio of London buildings, that single warranty is what makes the difference at procurement stage.
Proteus systems are particularly suited to the kind of work we do across Central London: flat and low-pitched roofs, complex parapet details, balconies, plant rooms, podium decks above habitable space, and refurbishments where stripping back to deck is not feasible. The cold-applied nature of the system means no naked flame on the roof, which is increasingly important for insurance compliance on residential and mixed-use blocks post-Grenfell.
We have seen too many flat roofs in London that were specified correctly but installed badly. A cheap reflashing job around a rooflight, an incorrect primer on a bituminous substrate, or a thin coat on a high-traffic area can fail within two winters. Manufacturer certification closes that gap.
A roof warranty is only worth as much as the chain of evidence behind it. Proteus gives you that chain, on paper, signed off at every stage.
For domestic clients, the Proteus pathway is equally relevant. A flat roof extension, a dormer or a garage conversion that uses a Proteus Pro-Felt or Cold Melt detail gives the homeowner something a generic flat roof never offers: a transferable warranty that survives a future sale of the property. Estate agents and surveyors in West London increasingly ask for it.
What to look for before you sign
If you are reviewing tenders for a roofing package, ask three questions. First, is the contractor currently listed on the manufacturer's approved register, not just historically? Second, will the manufacturer issue a system warranty directly to you, the client, on completion? Third, will a manufacturer representative attend site for the pre-start meeting and at least one mid-works inspection? If the answer to any of these is no, you do not have a certified install. You have a coating.
KC BUILT's typical Proteus package covers a full pre-installation roof survey, removal and reinstatement of plant where required, substrate priming, primary membrane installation, detailing around penetrations and upstands, and a manufacturer-issued warranty document handed over at practical completion. We are happy to share previous project files and warranty certificates on request as part of any pre-qualification.
If you have an upcoming flat roof refurbishment in London, whether it is a single Victorian terrace extension or a multi-block housing scheme, we can quote on a Proteus-specified basis from a drawing pack, a survey, or a tender NBS document. Get in touch through our contact page and we will arrange a site visit.
