JW Flat Roofing Waterproofing Solutions
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Dorset's
flat-roof
specialists.

40 years on the tools. 25-year warranty on every job. Free drone survey with every quote. GRP, EPDM and felt — Dorchester to Southampton, anywhere below the M4.

Recent work

Failing felt → fresh GRP.

Drag the handle to see the difference.

Before
After
What I do

Flat roofs, done right. Nothing else.

40 years specialising in one thing — flat-roof systems that actually hold up. GRP, EPDM, felt. Commercial and residential.

Free drone survey

I fly the drone over your roof before I quote. You see every failing seam, blister and ponding zone from above — no guesswork, no climbing, no surprise extras.

GRP fibreglass

Seamless cold-applied systems. 25-year material warranty. Glass-smooth finish, no laps to fail, handles UK weather for decades.

EPDM rubber

Single-ply rubber membrane, installed in one sheet on most domestic roofs. 50-year potential life, fully recyclable, fire-resistant.

Felt & bitumen

Torch-on mineral felt, three-layer builds, cap-sheet overlays. Traditional, cost-effective, still the right choice on the right job.

Flat roof repairs

Leak diagnosis, seam work, patch overlays. Fix it properly first time so you're not paying twice in three winters.

Full re-roofing

Strip back to the deck, replace rotten boards, lay new insulation & vapour control, finish in GRP/EPDM/felt. Fresh build-up, 25-year guarantee.

Commercial & large-span

Factories, schools, warehouses, extensions. Membrane systems for flat roofs above 200m², built to commercial-grade specs.

Dormers & garages

Domestic specialists work — tight junctions, small-span roofs, bay-window tops. The finicky stuff that separates pros from bodgers.

Lead outlets & detailing

Lead outlet chutes, cover flashings, skirts, upstands. Code 4/5 lead properly dressed — the fiddly details that decide whether a roof lasts 5 years or 30.

Also: waterproofing membranes · roof lanterns & skylights · firings & falls · insulation overlays · parapet detailing · flat-to-pitched conversions

The build-up

The anatomy of a 25-year flat roof.

Most flat-roof failures come from the layers you can't see. Tap the material tabs to see how each system stacks up — and why every layer matters.

01
GRP topcoat & membrane
Pigmented gel + glass-reinforced plastic. Seamless, UV-stable, 25-year warranty.
02
Bonded fleece & adhesive
Full-bond to the substrate below. No air pockets, no movement, no lift.
03
PIR rigid insulation
100–150mm. U-value 0.15 or better. Meets Building Regs Part L, warmer than it has to be.
04
Vapour control layer
Stops warm moist air rising into the insulation. Skip this and you'll rot the deck from below — every time.
05
Structural deck
18mm OSB, ply, or concrete. Rotten boards replaced before anything else goes on — non-negotiable.

Every layer earns its keep.

Skip the vapour barrier — the deck rots. Cheap-out on insulation — condensation destroys the build-up. Wrong membrane for the spec — leaks within 3 winters.

I've seen every mistake roofers make. My build-ups last because every layer is specified right for the job — commercial or domestic, GRP or felt, flat or falls.

40+
years on the tools
25yr
material warranty
0£
drone survey
Book my free drone survey
Why me

A flat-roof specialist. Not a general roofer.

Based in Dorchester. Covering Poole, Bournemouth, Southampton and anywhere below the M4. When you ring, you're speaking to the owner — 40 years on the tools, and the bloke who'll be on your roof. No call centres, no subcontractors.

JW
JW Flat Roofing
Owner-operated. Surveyor, fitter, same pair of hands.

40+ years on the tools

Four decades of flat-roofing only. Every failure mode, every material, every trick the cowboys use — I've seen it and learned the fix.

25-year material warranty

Every GRP and EPDM job carries a 25–30 year manufacturer warranty on the materials. In writing, on every invoice.

Free drone survey

I fly the drone before I quote. You see every failing seam, blister and ponding zone from above — no guesswork, no upselling, no surprise extras.

Fixed-price written quotes

Free survey, fixed price in writing, no surprise extras. What's quoted is what you pay — no VAT surprises, no "while we're up there" add-ons.

How it works

Four steps. No faff.

01

Get in touch

Call, text, or drop the form below. I'll get back to you the same working day.

02

Free drone survey

I fly the drone over the roof. You see every problem without needing a ladder. Surveys booked within 24–48 hours.

03

Agree & book

Quote in writing, dates agreed. No deposit required on standard jobs under £2k.

04

Job done

Before-and-after photos, receipts, clean site left behind. Pay by bank transfer, card, or cash.

Where I work

Dorchester to Southampton — anywhere below the M4.

Based in Dorchester, covering the whole south coast on a daily basis. If your town isn't on the list — ring anyway. Drive time permitting, I cover anywhere below the M4 corridor.

Check your area
Dorchester Weymouth Poole Bournemouth Christchurch Southampton Winchester Salisbury Yeovil Wareham Swanage Blandford Forum Sherborne Wimborne Minster Ferndown Bridport Lyme Regis Shaftesbury Gillingham Ringwood Fordingbridge New Milton Lymington Eastleigh Fareham Romsey

+ surrounding villages. Based in Dorchester, working anywhere below the M4 corridor.

Get in touch

Tell me what's up with the roof.

Free quotes within 24 hours. Drone survey with every quote — I'll come out, fly the roof, and have a proper written price back to you quickly.

Phone
07737 032604
Base
Dorchester, Dorset
Hours
7am–7pm, Mon–Sat

Free drone survey booked within 24 hours. Prefer to chat? Call the number.