- Price per m²
- £93–£149
- Typical life
- 25–35+ years
- Manufacturer guarantees
- 20–25 year guarantees on specified systems
- Typical garage roof
- £2,100–£3,450
Dorset at a glance
How much does a single-ply roof cost in Dorset?
Guide prices including VAT at South West rates. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Commercial roof (100 m²), single-ply + insulation | £13,650–£22,450 |
| Single garage (18 m²), single-ply | £2,100–£3,450 |
| Single garage (18 m²), EPDM rubber | £1,650–£2,900 |
| Extension (20 m²), EPDM, new deck + insulation | £2,900–£5,050 |
Which flat roofs are common in Dorset?
Flat roofs in Dorset sit on lock-up garage blocks on estates, 1960s and 1970s link-detached houses with flat-roofed garages and porches and bungalows with flat-roofed side extensions and dormers. The South West averages roughly 1,260 mm of rain a year and many roofs face wind off the Atlantic, so we specify fixings and edge details for wind uplift as well as drainage. Approximate 1991–2020 regional averages based on Met Office data.
Building regulations in England
Replacing more than half of a roof over a heated room usually counts as renovating a thermal element, so it is insulated to current standards and notified to building control. Renovated roofs over heated rooms are insulated to around 0.16 W/m²K where that's feasible, and new extension roofs are built to 0.15 W/m²K. In Dorset the application goes to BCP Council and Dorset Council. More on the rules.
Should a single-ply roof be mechanically fixed or adhered, and how are the seams welded?
Most commercial single-ply roofs are mechanically fixed, while adhered systems suit decks that cannot take fixings or roofs where a smooth finish is wanted. The choice depends on the deck, the wind exposure of the site and the manufacturer's specification.
| Method | How it works | Typical use |
|---|---|---|
| Mechanically fixed | Fasteners and plates hold the membrane through the insulation into the deck, hidden under the lap of the next sheet | Metal, timber and concrete decks on commercial roofs |
| Adhered | Membrane bonded to the insulation or deck with adhesive | Domestic roofs, roofs where fixings are unsuitable |
| Ballasted | Loose-laid and held down by paving, gravel or a green roof | Inverted roofs, terraces, green roofs |
Fixing patterns are worked out for the site, with more fasteners at corners and perimeters, where wind uplift is strongest.
Seams are welded by hot-air machines and hand tools that melt the overlapping edges so they fuse. Each seam is then probed along its length to find any gaps, and test welds are made at the start of the day to set the machine for the weather. On commercial jobs we also check that walkways protect the membrane around plant.
How long does a single-ply roof last, and what guarantee comes with it?
A well-installed single-ply roof typically lasts 25 to 35 years or more. Its life depends mostly on the quality of the welds, the fixing pattern, protection from foot traffic and keeping outlets clear.
Signs of trouble on an older single-ply roof include seams lifting at the edges, shrinkage pulling at upstands and corners, punctures near plant, and loose fixings under the membrane on windy sites.
Manufacturer guarantees are available on many specified single-ply systems, and they often depend on a registered build-up, an inspection and sometimes an approved installer. Where the system allows, we complete that registration on your behalf. On every re-roof you also receive our written workmanship guarantee, with the length set out in the quote, and you can ask about insurance-backed options. See the guarantees guide and maintenance guide for more.
Which towns in Dorset do we cover?
Single-ply membrane roofing in Dorset: questions
Which towns in Dorset do you cover?
All of Dorset. The main towns have their own pages below, and if yours isn't listed we still cover it: send your postcode and we'll confirm.
How much does a single-ply roof cost in Dorset?
£13,650–£22,450 for a 100 m² commercial roof in single-ply with insulation, at South West guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Which postcode areas do you cover in Dorset?
All of Dorset, including the BH, DT postcode areas. Send your full postcode and we'll confirm.
Can a single-ply roof be repaired?
Yes. A compatible patch is cleaned and hot-air welded over the damage. Older membranes may need extra cleaning before they weld properly, which the team checks on site.
Can single-ply be used on a house?
Yes. It can be used on garages, extensions and dormers, usually adhered rather than mechanically fixed. On small domestic roofs, though, EPDM or GRP is often more economical.
How long does a commercial single-ply roof take?
A roof of around 100 m² typically takes several days, depending on strip-out, insulation, details and weather. Work is phased so the building stays weathertight and occupied areas are protected.
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