Loft Maker London
GRP Flat Roofing in London and Essex
A single welded, joint-free membrane with no tiles to slip. A durable flat roof for extensions, garages, porches and full roof replacements.
GRP is glass-fibre reinforced polyester. It is applied as a liquid resin reinforced with chopped glass fibre, in layers, onto a prepared deck, and it cures into a single continuous sheet. There are no laps, no joints between rolls and no individual tiles or sheets that can fail. When the layers are properly laid, the weak points that cause most flat roof leaks simply do not exist.
For a homeowner that matters because flat roofs fail at the edges and the junctions. Upstands, kerbs, gutter edges, pipe penetrations and the junction where a flat roof meets a wall are where water gets in. A welded GRP system forms those details as part of the same continuous surface, which is why it is a good specification for extensions, garages, porches, balconies and balcony roofs in a wet climate.
Where GRP makes sense
GRP suits flat and very low-pitch roofs: single-storey extensions, side returns, porches, dormer and garage roofs, and balcony or terrace roofs. It also works well as a full replacement where an older flat roof has reached the end of its life and the covering needs renewing.
It is less suitable as a primary covering on a steeply pitched roof, where a traditional slate or tile is both possible and preferable. We will tell you if that is the case rather than installing a flat roof system where a pitched one belongs.
The deck is what matters
A GRP roof is only as good as the deck and the detail. The deck has to be sound, dry, clean and free of movement, and it has to be specified so the resin bonds properly. Where the existing roof is being replaced we strip it back, assess the structure and the fall, and rebuild the falls so water drains towards the outlet rather than sitting in a pond.
Upstands, edge restraint, rainwater goods and any rooflight or vent penetrations are formed as part of the same system, and the whole thing is terminated neatly rather than being cut off at the wall.
Planning and building regulations
Replacing the covering of an existing flat roof is usually straightforward. A new flat roof as part of a new extension is part of that extension's consent, whether that is a householder planning application or permitted development. Where a new flat roof raises the height of the building or forms a terrace, the height limits that apply to the extension as a whole apply to the roof too.
Building regulations approval covers the roof build-up, fire performance, thermal insulation and the overall height of the extension. The structural and fire spread requirements around roof edges and upstands are checked as part of that approval, and the work is completed with a completion certificate.
What is included, and how long it takes
Site inspection and assessment of the existing deck, strip-back and preparation, falls and drainage, the GRP build-up, upstands and edge detailing, flashings, new rainwater goods where needed, and the completion certificate. A straightforward single-storey extension roof is normally a short programme, measured in days rather than weeks, but it is usually part of a larger project. Every project carries a 10-year structural warranty.
Related services
- Side Extensions London & Essex — The side return is usually the most under-used space on a London plot. Filling it with a well-designed extension is the cheapest way to add a proper room.
- Loft Conversions London & Essex — Turn unused roof space into a bedroom, bathroom or home office. We handle design, consents, structure and the build.
- Structural Steel Installation London — Beams, posts and frames that let you take out a load-bearing wall or open up a plan, calculated by an engineer, fabricated and installed by us.
Frequently asked questions
How long does a GRP flat roof last?
A properly installed GRP system is designed for a long service life, and it is a widely specified system for extensions and balconies. We are not going to quote a lifespan figure without seeing the deck, the falls and the details, and the manufacturer's warranty terms apply to the specific system installed.
Is GRP better than EPDM or a traditional flat roof?
All three can give a good result if they are installed properly. GRP is a rigid, welded, joint-free system that does not puncture easily and does not lift at the edges. EPDM is a single large membrane that is also joint-free but softer. The right answer depends on the deck, the detailing and how the roof will be used.
Can you put a GRP roof on my existing flat roof without stripping it?
Sometimes, but only where the existing deck and the build-up are sound and compatible. We assess the existing roof first, because building a new system over a wet, failing build-up just traps the problem. Where the covering is at the end of its life, stripping back and rebuilding the falls is normally the right answer.
Do you do flat roofs for garages and porches?
Yes. Flat and low-pitch roofs on garages, porches, outbuildings, side returns and dormers are all straightforward GRP work, and we can combine them with the extension or conversion programme rather than treating them as a separate job.
Do I need planning permission to replace a flat roof?
Usually not, if you are replacing the covering like for like and not changing the height or the appearance of the roof. It is still worth checking, particularly in a conservation area or where the new roof forms a terrace, because those change what is allowed.
How long does GRP flat roofing last?
A properly installed GRP system is expected to last for decades with relatively little maintenance. The lifespan depends far more on the preparation of the deck, the detailing at edges and penetrations, and the quality of the installation than on the material itself.
Can you replace an existing flat roof while I stay in the house?
In most cases yes. We can work in phases and use temporary weather protection, so the area is covered as the old roof is stripped. If the structure beneath needs work, we will tell you before we start.
What does Loft Maker London do?
We are a London and Essex construction company specialising in loft conversions, dormer and mansard roof construction, side extensions, GRP flat roofing and structural steelwork. We handle design, planning, structural engineering, groundworks, roofing and finishing in-house, so you deal with one team from first drawings to handover.
Which areas do you cover?
We work across London and Essex, including Chingford and South Woodford. We are a mobile, service-area business, so we come to you rather than asking you to visit an office.
How much does a loft conversion cost?
It depends on the property, the specification and how much of the work is structural. A straightforward conversion in an existing roof space costs less than one that needs a new structural opening, steelwork or extensive roof construction. We price every project individually and give you a clear written quote before work starts, so there is no ambiguity about what you are paying for.
Do I need planning permission for a loft conversion?
Not always, but it depends on the property and the work. Many loft conversions fall within permitted development, while mansard roofs, dormer windows in conservation areas, and work that changes the volume of a dwelling often need planning permission. Building Regulations approval is a separate requirement and applies to most structural work. We assess your specific property, tell you exactly which permissions are needed, and handle the applications.
How long does a loft conversion take?
A conversion that does not require planning permission is often built in two to three weeks on site, but the full project - surveys, designs, approvals, build and finishing - takes considerably longer. Projects involving a mansard roof, an extension or steelwork take longer again. We give you a realistic programme with the quote, and we keep you informed if anything changes.
Is my project covered by a warranty?
Every project we complete is backed by a 10-year structural warranty. The full policy wording and schedule of cover are issued to you at handover, so you know exactly what is covered and what to do if you need to make a claim.
Do you handle Party Wall notices?
Yes. Where your project affects a neighbouring property, Party Wall notices or an award may be required before work starts. We prepare the necessary paperwork, serve the notices and coordinate with the adjoining owner's surveyor where one is appointed.
Can you work from drawings we already have?
Yes. If you have planning approval, architectural drawings or structural calculations, we can price and build from them. If you would rather we took the design and planning on as well, we can do that instead - just tell us which stage you have reached.
Can you match an existing roof or extension?
Yes. We work with a range of roof tiles and finishes, and we match existing materials where we are extending or building alongside original fabric, so the finished work reads as part of the house rather than an addition to it.
What happens after I get in touch?
We arrange a free, no-obligation consultation at your property. We look at the space, discuss what you want to achieve and any constraints, and then come back to you with options and a clear written quote. There is no obligation to proceed.
Tell us about your project
Send a few details and we'll come back to you with honest advice on what is possible, what it involves and how long it takes.