Flat Roof Replacement and Waterproofing in London
Full flat roof replacements, refurbishments and waterproof overlays for houses, blocks of flats and commercial buildings. Based in Croydon, covering South London and Greater London.
A better way to replace a flat roof
Replacing a flat roof does not have to mean stripping it first. Where the structure is sound, we replace the waterproofing itself:
- A waterproof overlay applied over your existing roof. No tear-off, no skip, minimal disruption.
- A certified liquid-applied waterproofing system with a 10-year product guarantee.
- Installed by HYDRONYLON® Approved Contractors across London.
- Free drone roof inspection with a written condition report.
How it works
- Free inspection. We survey your roof with a drone and on foot.
- Written report. You receive a condition report and a clear specification.
- Installation. An Approved Contractor installs the system to our specification.
- Guarantee. The work is covered by a 10-year product guarantee.
Overlay instead of tear-off
An old felt or asphalt flat roof does not have to be stripped back to the deck. Once the substrate has been cleaned and prepared, the liquid-applied waterproofing system is applied directly over the existing covering. That means no skip outside the building, no opening up the roof to the weather, and far less risk of an unexpected leak during the works. The system holds a European Technical Assessment (ETA-23/0735).
When a full replacement is the right call
Not every roof should be overlaid. If the deck beneath the covering is wet, rotten or structurally failing, sealing over it would only trap the problem, and we will tell you so. In that case the honest route is a full replacement, and the inspection report will say exactly that. The survey comes first, so you know which case your roof is in before any work is priced.
Recent flat roof projects in London
Real London roofs renewed with the HYDRONYLON system rather than stripped and replaced.
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Leaking felt roof sealed in Shepherd's Bush, London W12 Felt · 65 m² · 6 August 2025 A worn felt flat roof in Shepherd's Bush, London W12: all 65 m² sealed with the HYDRONYLON liquid-applied system in four working days, no strip-off. Read case study → -
Leaking lead and parapet roof sealed in Whitechapel, London E1 Lead & parapet · 78 m² · 18 August 2024 A leaking lead parapet roof on Whitechapel Road, London E1, sealed with the HYDRONYLON liquid-applied system, with no lead replacement or tear-off. Read case study →
Get a free roof assessment
Leave your details and, if you like, a few photos of your roof. We will get back to you with an assessment. No obligation.
Thank you - we'll be in touch within one working day.
Frequently asked questions
Is my roof suitable for an overlay?
The inspection and the written report settle this. Most felt, asphalt, metal and PVC roofs in sound structural condition can be overlaid. Some roofs do need a full replacement, and when that is the honest answer, that is what we recommend.
How long does the work take?
Typically days rather than weeks, depending on the size and condition of the roof. An overlay is quicker than a full tear-off because the existing covering stays in place.
Do you do small repairs?
We focus on full replacements, refurbishments and overlays. For small repairs we can connect you with an Approved Contractor near you.