- Guide price
- £16,000–£28,000
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
Dorset at a glance
How much does a block or HMO 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 |
|---|---|
| Block of flats (150 m²), felt + insulation + scaffold | £16,000–£28,000 |
| Commercial roof (100 m²), single-ply + insulation | £13,650–£22,450 |
Which flat roofs are common in Dorset?
Flat roofs in Dorset sit on lock-up garage blocks on estates, newer estates where the first extension roofs are now being replaced and terraced streets with flat-roofed rear kitchens and bathrooms. 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.
Do fire and insulation rules affect block roofs?
Yes. Where a roof is close to a boundary, building regulations limit which coverings can be used, and the build-up should carry a suitable external fire classification such as BROOF(t4); in England this is covered by Approved Document B.
BROOF(t4) applies to a tested build-up, so we check that the manufacturer's classification covers the deck, insulation and membrane actually being installed, not just the membrane name. Where the roof crosses a separating or compartment wall, the fire-stopping detail is kept intact.
Re-covering more than half of a roof over heated flats usually triggers the thermal element rules, so the insulation is upgraded towards the renovation U-value where feasible: 0.16 W/m²K for dwellings in England and Wales. We handle building control where it is needed. See building regulations and warm vs cold roofs.
Which roofing systems last longest on a block of flats?
Mastic asphalt, EPDM, single-ply and high-performance built-up felt all give long service lives on block roofs; the right choice depends on the deck, how the roof is used, the details and the whole-life cost.
- Mastic asphalt: 30–60 years with maintenance, common on concrete-decked blocks and walkways. See mastic asphalt roofing.
- EPDM: 25–50 years, laid in large sheets with few joins.
- Single-ply: 25–35+ years, quick to lay on larger roofs, with welded laps. See single-ply roofing.
- Built-up felt: 15–25 years for modern torch-on systems and longer for high-performance systems, robust where maintenance teams walk the roof.
- Liquid-applied: 10–25+ years by product, useful as an overlay on a sound roof with complex details.
The cheapest roof today is not always the cheapest over the life of the building. A longer-life system, with tapered insulation to cure ponding, can mean fewer reactive repairs and fewer rounds of consultation. These lives are indicative and assume good specification and regular maintenance.
Which towns in Dorset do we cover?
Flats, HMOs and block roofs 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 block or HMO roof cost in Dorset?
£16,000–£28,000 for a 150 m² block-of-flats roof in felt with insulation and scaffold, 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.
Do residents need to move out during a re-roof?
No. Block roofs are normally replaced with residents in place, and if we need to check a ceiling inside a top-floor flat, access is arranged through the agent or landlord.
Can a block roof be replaced in phases?
Yes. Larger roofs can be split into sections over one or more budget years, with each phase priced separately and each section left watertight before the team leaves site.
Does a block roof replacement need building control?
Usually, yes. Re-covering more than half of a roof over heated flats normally triggers the thermal element rules, which bring insulation and approval requirements, and we handle building control or building standards where it is needed.
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