New EPDM flat roof with roof lanterns installed by White Horse Roofing, Oxfordshire

Flat Roofing · Oxfordshire, Berkshire & the Cotswolds

Flat Roofing in
Oxfordshire — EPDM, Felt
& Fibreglass Systems.

Long-life flat roof systems installed and repaired to manufacturer standards — with a 10-year workmanship guarantee and none of the pond-and-patch problems that give flat roofs a bad name.

Get Your Free Quote 07522 468971

10-year flat-roof workmanship guarantee · £1M public liability

Established 2017

1,500+ Jobs Completed

15-Yr Workmanship Guarantee

£1M Public Liability Insurance

Checkatrade 9.78/10

The Service

What flat roofing is,
and who it's for.

A flat roof is only as good as the person laying it. The materials themselves — good-quality EPDM, high-performance modified-bitumen felt, GRP fibreglass — will comfortably run 20 to 30 years. What fails first is the detailing: the upstands, the corners, the outlets, the joints. That is where a proper installer earns their fee.

White Horse Roofing installs and repairs flat roofs across Oxfordshire, Berkshire and the Cotswolds. Extensions, dormers, garages, porches, outbuildings — all systems, all sizes, all backed by a written 10-year workmanship guarantee.

Who it's for

Homeowners with a flat-roof extension, garage, dormer or porch that is leaking, ponding, blistering or approaching the end of its life. Homebuyers whose survey has flagged a failing felt roof. Landlords who need a documented, warrantied replacement rather than another year of patching.

When it's needed

As soon as you see ponding after rain, splits or blisters in the surface, moss growing on the covering, or water staining the ceiling below. Once a flat roof is admitting water, deterioration accelerates rapidly — the deck below saturates and rots, and a straightforward re-cover becomes a full strip-and-rebuild.

Why professional

Flat-roof failure is almost always a detailing failure — a badly formed upstand, a joint that was not welded fully, an outlet without adequate fall. Manufacturer warranties on EPDM and GRP are only valid when installed to specification by a competent tradesperson. DIY felt roofs and unqualified fitters routinely void those warranties on day one.

What Happens If Ignored

The cost of leaving it
until next winter.

A leaking flat roof rots the timber deck beneath it silently and quickly. What starts as a small dark patch on the ceiling below becomes a saturated joist, a collapsed section of plasterboard, and eventually a full deck replacement — often at 2 to 3 times the cost of an intervention 18 months earlier.

Common problems we see

Ponding water and inadequate falls
Split, blistered or perished felt surfaces
Failed upstands, corners and outlet detailing
Rotten timber decks under aged coverings

Mistakes to avoid

×Overlaying new felt on top of an existing failed system — traps moisture, guarantees premature failure
×Skipping firring pieces to create proper falls — the number-one cause of ponding and premature ageing
×Using unrated adhesives on EPDM — bond fails inside 2 years and the sheet lifts in wind

Our Process

Five steps. No day rates.
No surprises.

Survey & System Choice

Roof assessed, deck condition checked, size and use of the roof considered. We recommend EPDM, felt or GRP based on the roof — not on what we prefer to fit.

Fixed Quote

Written itemised quote — strip-off, deck replacement (if needed), insulation upgrade (if chosen), covering, all detailing and disposal included at a fixed price.

Strip & Deck Prep

Existing covering removed, deck inspected and repaired or replaced as needed. Firring pieces installed where falls are inadequate.

Install

Chosen system installed to full manufacturer specification — bonded, welded or cured as the material requires. All upstands, outlets and terminations detailed correctly.

Sign-Off & 10-Year Guarantee

Water test where practical, photographic record, site cleared. Written 10-year workmanship guarantee issued alongside any applicable manufacturer product warranty.

Recent Work

Real jobs, real roofs.

Recent flat roofing projects completed by White Horse Roofing Services across Oxfordshire, Berkshire and the Cotswolds.

Flat roof — after photo 1 by White Horse Roofing Services, Oxfordshire — Flat roof replacement — drag to compare before & after.

Flat roof — after photo 2 by White Horse Roofing Services, Oxfordshire — Flat roof replacement — drag to compare before & after.

Flat roof — after photo 3 by White Horse Roofing Services, Oxfordshire — Flat roof replacement — drag to compare before & after.

Flat roof — after photo 4 by White Horse Roofing Services, Oxfordshire — Flat roof replacement — drag to compare before & after.

Flat roof — after photo 5 by White Horse Roofing Services, Oxfordshire — Flat roof replacement — drag to compare before & after.

Flat roof — after photo 6 by White Horse Roofing Services, Oxfordshire

What You Get

Specific benefits.
No vague claims.

Every point below is something we do on every job — not a marketing line. Ask us at the survey and we'll show you exactly how.

10-Year Guarantee

Every flat-roof installation carries a written 10-year workmanship guarantee.

System-Right Fit

EPDM, felt or GRP chosen for the roof — not the fitter's convenience.

Proper Falls Designed In

Firring pieces added where required so water actually leaves the roof.

Deck Repaired First

Rotten timber replaced before covering goes down. Never covered over.

Manufacturer-Grade Detailing

Upstands, terminations and outlets to full spec — the parts that actually fail.

Clean Removal

Old covering, insulation and waste removed and disposed of properly.

In Detail

The specifics —
materials, methods, situations.

Flat-roof systems we install

EPDM rubber — single-ply, one-piece where practical, cold-applied with manufacturer-approved contact adhesive. Excellent lifespan (25+ years), highly resistant to UV and temperature cycling, and forgiving to work around detailing.

High-performance modified-bitumen felt — a torch-on or self-adhesive three-layer system with a mineral-finish cap sheet. Long-standing, cost-effective and well-suited to garages, outbuildings and traditional flat-roof extensions where budget is a driver.

GRP fibreglass — a laminated in-situ system that cures to a single seamless surface. Ideal for balconies, complex shapes and roofs where foot traffic is expected.

Detailing that actually matters

Falls: every flat roof needs a minimum 1:80 fall to shed water. Where the deck is level or badly laid, we install firring pieces before the covering goes down. Ponding voids most manufacturer warranties.

Upstands: minimum 150 mm above finished roof level, dressed and terminated correctly against walls, chimneys and abutments. This is where most cheap flat roofs fail first.

Outlets: sized correctly for the roof area, properly bonded into the covering, with leaf guards where appropriate. Undersized outlets are a common cause of overflow and lateral water damage.

Residential and commercial

We work on domestic extensions, dormers, garages, porches and outbuildings — and on small commercial roofs including workshops, small offices and community buildings. Insurance documentation, method statements and RAMS available on request for commercial work.

Related services

Flat Roofing available in

Not sure if we cover your postcode? Ask us

FAQ

Everything homeowners
ask us about flat roofing.

Something not covered? Call 07522 468971 and we'll answer it directly.

How much does a flat roof cost?+

As a rough guide: garage-sized felt roofs from £1,800, EPDM extensions from £2,500 to £6,000, larger or GRP jobs quoted individually. Every project is fixed price in writing after survey — including strip-off, deck repairs, insulation and disposal.

How long will a new flat roof last?+

EPDM: typically 25 to 30+ years. High-performance felt: 20 to 25 years. GRP: 20 to 25 years. All materials perform to the top of these ranges only when installed and detailed correctly — which is why our 10-year workmanship guarantee focuses on the installation itself.

EPDM vs felt vs fibreglass — which should I choose?+

EPDM is our default recommendation for most domestic flat roofs — long-lived, forgiving and cost-effective. Felt still makes sense on tight budgets and simple roofs. GRP is the right answer for balconies, roof terraces and complex shapes where foot traffic and appearance matter.

Can you overlay my existing flat roof?+

Very rarely, and only after full inspection of the deck below. Overlaying a failed roof usually traps moisture and shortens the life of the new covering. We strip and replace as the default, and only overlay when it is genuinely the right call.

Do I need building regulations approval?+

Full flat-roof replacement over 25% of the roof area normally triggers a requirement for building regulations upgrade of the insulation. We handle this with the covering install so it is done once and correctly.

Do you offer emergency flat roofing call-outs?+

Yes. For storm damage, active leaks and make-safes across Oxfordshire, Berkshire and the Cotswolds, call us and we will aim to get a surveyor to you the same day. Emergency temporary works can usually be carried out on the first visit so the property is watertight before a permanent repair is scheduled.

Is the quote free?+

Yes for owner-occupied properties. For homes you have not yet bought there is a £100 pre-purchase survey fee — fully deducted from the final quote if you go ahead. Every quote is fixed price, in writing, itemised and never a day rate.

What guarantee do you offer?+

Full re-roofs carry a 15-year workmanship guarantee. Flat roofs carry a 10-year workmanship guarantee. Repairs are covered by a written workmanship warranty appropriate to the scope. All work is backed by £1M public liability cover.

How do payments work?+

A deposit secures your slot in the diary. The balance is paid by bank transfer on completion. On larger projects we offer sensible stage payments so you are never paying ahead of the work delivered.

Which areas do you cover?+

Oxfordshire, Berkshire and the Cotswolds — including Oxford, Abingdon, Didcot, Wantage, Witney, Reading, Newbury, Cirencester and Faringdon. If you are close to the edge of that radius, call us — we can usually help.

Ready to sort it?

Book a same-day survey
and a fixed-price quote.

Family-run, fully insured, and backed in writing. Every quote is fixed price — no day rates, no drift. Call us or send a few details and we'll be in touch today.