Flat roof refurbishment in London

Signs your flat roof is ready for refurbishment

Refurbishment is for a roof that is tired across the whole surface, not one with a single fault. The signs are usually cumulative: the covering has gone brittle, blistered or crazed over most of the roof; you have patched the same roof more than once and the repairs keep moving; water sits and drains slowly after rain; moss and growth have taken hold. On their own, each of these is a maintenance job. Together they say the surface has reached the end of its service life and the whole roof needs renewing, not another patch.

The point many building owners miss is that reaching this stage does not automatically mean a full re-roof. A worn surface over a sound structure is exactly the roof that refurbishment is built for.

Refurbish or replace? What actually decides it

The deciding factor is not the surface you can see, it is the deck underneath. If the deck is solid and dry and only the covering is worn, the roof is a strong candidate for refurbishment: the existing covering is prepared and sealed over, and the roof stays in place. If the deck is wet, rotten or structurally failing, sealing over it would only trap the problem, and a full replacement is the right answer.

That is why refurbishment starts with a survey rather than a quote. An Approved Contractor checks the structure, the falls and the drainage before recommending anything, so you find out which situation your roof is actually in. Where the structure is sound, refurbishment usually costs considerably less than a full re-roof and is far less disruptive, because there is no strip-off, no skips and no days with the building open to the weather. Our guide to flat roof refurbishment cost sets out what drives the price.

What a flat roof refurbishment involves

A refurbishment is carried out over the existing roof, in a few stages. The roof is surveyed, then cleaned and prepared, and any local defects are made good. A primer matched to the substrate is applied, then the liquid waterproofing with mesh reinforcement, worked into the laps, upstands and details where flat roofs usually fail first. The exact preparation is matched to the covering, so a worn asphalt flat roof overlay is made good differently from felt or single-ply. It cures into one continuous, seamless surface across the whole roof.

For the building, this means the work is contained: the covering is not torn off, so there are no skips and no exposed deck, the building stays in use throughout, and a typical refurbishment is a matter of days rather than weeks. The system is cold-applied, with no torches or hot works on the roof.

The HYDRONYLON system

The system fitted on these refurbishments is HYDRONYLON, assessed under European Technical Assessment ETA-23/0735. HYDRONYLON LTD supplies it; the work is carried out by Approved Contractors, trained and certified on the system and working across London. A roof refurbished by an Approved Contractor carries a 10-year product guarantee on the materials, issued to the contractor who does the work. You can see the build-up for each roof type on the applications page and the method step by step on the system page.