Who it is for
Homeowners with an extension, dormer, garage, porch or bay roof; commercial owners with larger decks, plant areas and parapet roofs; and anyone whose flat roof has been patched more than once.
Services · Flat Roofing Systems
Flat Roofing Systems
For Homes And Commercial
Property In Surrey
Extensions, dormers, garages, porches and commercial decks covered in the system that suits the roof — installed to falls, detailed at the upstands, and backed by a 15-year guarantee plus the manufacturer's own.
15-year flat roof guarantee · Manufacturer-backed system guarantee passed to you · £1,000,000 public liability cover
Roof leaking right now?
We run 24/7 emergency cover. A £150 call-out gets a roofer to the property to make it safe and stop the water, with the repair priced before any further work.
Call 07808 839833Emergency line answered day and night
60+ years of family roofing knowledge
£1,000,000 public liability cover
24/7 emergency call-out available
Rated by homeowners on Google
Recent Flat Roofing Systems
Work we have completed
- 15-year
- Flat roof guarantee
- 4
- Systems installed
- £1m
- Public liability cover
- Free
- Survey for homeowners
- 60+ yrs
- Family roofing knowledge
Overview
What a flat roofing system is — and what it is not
A flat roof is a system, not a sheet of material. It is a deck, a vapour path, insulation where required, a waterproof layer, a set of falls that move water to an outlet, and detailing at every upstand, kerb, outlet and edge. Nine times out of ten a flat roof fails at one of those details rather than in the middle of the field, which is why the specification and the workmanship at the edges matter more than the brand printed on the roll.
We install and repair four systems: three-layer built-up felt, EPDM rubber membrane, single ply, and GRP fibreglass. Each has a place. Each comes with a manufacturer-backed guarantee that is passed on to you, and every flat roof installation we carry out carries our own 15-year guarantee on top of that.
Flat roofs are also the part of a house most often built badly by someone else. Extensions and dormers added in the 1970s and 80s frequently have no falls, no insulation to current standards and a covering that was already obsolete when it went on. Replacing one properly is usually cheaper over ten years than patching it three times.
When it is needed
When water ponds for days after rain, when the covering is blistered, split or crazed, when the ceiling below stains after every storm, when an extension is being built, or when a mineral felt roof is past twenty years old.
Why professional help matters
Falls, upstand heights, outlet positions and edge trims decide whether a flat roof lasts fifteen years or two. Those decisions are made before any material is unrolled and cannot be corrected afterwards.
What you get in writing
A specification naming the system and build-up, a written price, the 15-year guarantee, and the manufacturer's guarantee documentation for the system installed.
What Goes Wrong
What a failing flat roof does to the building below
Flat roofs sit directly over habitable rooms far more often than pitched roofs do. There is no loft to catch the water and no distance between the defect and the plaster.
Ponding accelerates every failure mode
Standing water finds pinholes, freezes in laps and doubles the UV and thermal stress on the covering. A roof that never drains is a roof on a countdown.
Saturated insulation and deck
Once water is inside a warm-deck build-up it does not evaporate. The insulation stops working, the deck softens, and a covering replacement turns into a full strip and rebuild.
Direct damage to rooms below
No loft void means the first sign is often a stained or bulging ceiling in a kitchen, bedroom or office — decoration, lighting and flooring all in the firing line.
Cold-bridge condensation
An under-insulated or wrongly built-up flat roof produces condensation that looks exactly like a leak and gets misdiagnosed as one, repeatedly.
Common mistakes we are called to fix
- Painting a liquid coating over a saturated felt roof and sealing the water inside.
- Patching a covering that has crazed across the whole area rather than replacing the system.
- Leaving upstands below 150mm because the door threshold or cladding got in the way.
- Fitting a new covering over the original deck without checking whether the deck is sound.
- Ignoring the outlet: most flat roof floods start at a blocked or undersized outlet, not at the membrane.
How It Works
From first call to
a guaranteed finish
- 01
Inspection
We check the covering, the falls, the outlets, the upstands and — where accessible — the deck and ceiling below, and establish whether you have a leak, a condensation problem, or both.
- 02
Diagnosis and system selection
We recommend the system that suits the roof: traffic, complexity of detail, exposure, appearance and budget all change the answer. You are told why, not just what.
- 03
Written quote and programme
The specification, build-up, insulation, falls and edge details are priced in writing, along with access and disposal. Free for homeowners; £150 for pre-purchase surveys, deducted from your quote if you proceed.
- 04
Strip, deck repair and installation
The old covering is stripped, the deck inspected and repaired, falls corrected where needed, insulation laid to the specified build-up, and the membrane installed with fully formed upstands, outlets and trims.
- 05
Water test, sign-off and guarantees
Falls and outlets are checked with water, the finished roof is walked with you, and you receive both our 15-year guarantee and the manufacturer-backed system guarantee.
What You Get
The outcome you are
actually paying for
Two guarantees, not one
Our 15-year installation guarantee plus the manufacturer-backed guarantee on the system itself, handed over in writing.
Drainage that actually works
Falls set to move water to the outlet, and outlets sized and positioned for the area they serve — the single biggest predictor of flat roof lifespan.
Warmer rooms below
Correct insulation build-up removes the cold bridge that makes flat-roofed extensions freezing in winter and streaming with condensation in the morning.
Fast installation, minimal disruption
Most domestic flat roofs are a short programme, and the building stays in use throughout.
Cost savings over patching
One correctly specified system outlasts a decade of repairs on a roof that was never going to hold.
Detailing done by roofers
Lead and membrane details at abutments, kerbs and parapets formed properly, by the same crew that does our pitched leadwork every week.
In Detail
Systems, build-ups and where each one belongs
Four systems, four different jobs. The right choice depends on the deck, the detail complexity, the foot traffic and the look you want from the window above.
Three-layer built-up felt
Modern built-up felt is a long way from the single-layer pour-and-roll of the 1970s. Torch-applied polyester-reinforced layers, a bonded underlayer and a mineral-finished cap sheet produce a robust, repairable, well-understood roof that copes with complex shapes and awkward upstands.
It suits garages, back additions, dormers and any roof with a lot of penetrations, because it is formed in place rather than cut from a sheet. It is also the easiest system to repair locally in ten years' time without touching the rest of the roof.
EPDM rubber membrane
EPDM is a single-piece synthetic rubber membrane, which means on a simple rectangular roof there are no seams at all in the field. It is highly resistant to UV and ozone, stays flexible in cold weather, and handles thermal movement well.
It is a strong choice for garages, extensions and outbuildings with clean geometry. Detailing at upstands and outlets is done with bonded corners and formed pieces, which is where installation quality shows.
Single ply
Single ply membranes are hot-air welded rather than bonded, producing seams that are as strong as the sheet. They are the standard for larger commercial areas because they cover ground quickly and handle plant, kerbs and multiple penetrations predictably.
Mechanically fastened or adhered depending on the deck and exposure, single ply also suits larger domestic flat roofs where a light-coloured finish is wanted for solar reflectance.
GRP fibreglass
GRP is laid up wet on a ply deck and cures into one seamless, rigid surface with the trims bonded into the laminate. It gives a hard-wearing finish suited to balconies, walk-on terraces and roofs where the surface will be used rather than just looked at.
It is deck- and weather-sensitive during installation: the ply must be dry and correctly fixed, and the cure needs the right conditions. Done properly it is one of the most durable domestic flat roof finishes available; rushed, it crazes.
Warm deck, cold deck and inverted build-ups
Warm deck construction places the insulation above the deck and below the waterproofing, keeping the structure at internal temperature and largely eliminating interstitial condensation. It is the default for new and replacement domestic flat roofs.
Cold deck build-ups, with insulation between joists and a ventilated void above, are common in older extensions and are the source of many misdiagnosed 'leaks' that are actually condensation. Where we replace a cold deck roof, we usually convert it. Inverted build-ups, with insulation above the membrane, appear on terraces and ballasted commercial roofs.
Residential and commercial differences
Domestic flat roofs are small, detail-heavy and highly visible from upstairs windows — appearance, upstand heights at doors, and neat edge trims matter.
Commercial flat roofs are area-driven: outlet capacity, plant penetrations, fall design, access for maintenance and phasing around occupancy. Single ply and built-up felt dominate, and works are programmed so the building keeps trading. We cover both from our Morden base across London, Surrey and the South East.
Where We Work
Based in Morden,
covering London and
the South East
- London
- Greater London
- Surrey
- Kent
- West Sussex
- East Sussex
- Hampshire
- Reading
- Isle of Wight
Questions
Flat Roofing Systems
questions we get asked
If your question is not here, call 07808 839833 and speak to a roofer rather than a call centre.
How much does a new flat roof cost?
It depends on area, system, insulation build-up, deck condition and access. The survey and written quote are free for existing homeowners, and the quote names the exact system and build-up so you can compare like with like.
How long does a flat roof last?
A correctly specified and installed system with working falls and outlets should give decades of service. We guarantee flat roof installations for 15 years, and the manufacturer-backed guarantee on the system is passed on to you as well.
Which system is best — felt, EPDM, single ply or GRP?
There is no universal best. Simple rectangular garage roofs suit EPDM, detail-heavy roofs suit built-up felt, large commercial areas suit single ply, and walk-on terraces suit GRP. We recommend based on your roof and explain the reasoning.
How long does the work take?
Most domestic flat roofs are a short programme of days, depending on area, deck repairs and weather. GRP in particular needs suitable conditions to cure, so we will not force it into the wrong week.
Can you repair my existing flat roof instead of replacing it?
Yes, where the covering has life left. Splits, blown laps, failed upstands and blocked outlets are all repairable. Where the covering has crazed or the build-up is saturated, a repair is money spent twice and we will tell you so.
Is water sitting on my flat roof a problem?
Persistent ponding is a warning sign. It usually means falls are inadequate or an outlet is blocked or badly positioned, and it accelerates every failure mode the covering has.
Do you insulate as part of the work?
Where the build-up requires it, yes. Converting an old cold deck to a warm deck usually solves both the heat loss and the condensation that gets mistaken for a leak.
Do you do commercial flat roofing?
Yes. Larger decks, plant areas and parapet roofs are handled with single ply or built-up felt, phased so the building stays operational.
Are you insured?
Yes. We hold £1,000,000 public liability cover and details are provided with every quote.
Do you cover emergencies on flat roofs?
Yes. We run 24/7 emergency cover with a £150 call-out for splits, blown coverings and blocked outlets causing ingress.
Free Estimate
Get your flat roof specified properly
Free survey for homeowners, a written specification naming the system and build-up, a 15-year guarantee and the manufacturer's guarantee passed straight on to you.