- Price per m²
- £93–£144
- Typical life
- 10–25+ years by product
- Manufacturer guarantees
- 10, 15 or 20-year guarantees by named system
- Typical garage roof
- £2,100–£3,350
Dorset at a glance
How much does a liquid-applied 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 |
|---|---|
| Single garage (18 m²), liquid-applied | £2,100–£3,350 |
| Balcony (12 m²), liquid-applied, scaffold | £1,950–£3,350 |
| 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 newer estates where the first extension roofs are now being replaced, 1930s semis with flat-roofed garages and kitchen extensions and low-rise post-war blocks of flats. 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 building regulations apply if a liquid coating goes over my roof?
They can. In England, Wales and Northern Ireland, re-covering more than half of a roof over a heated room is usually renovation of a thermal element, even when the new membrane goes over the old, so the roof should be insulated towards the renovation standard where feasible; for a Scottish property, the local building standards team will confirm whether a warrant is required.
A minor coating repair to a small area is different from re-covering the whole roof. Where insulation is needed, an overlay is not always practical, because the insulation has to go under a new waterproof layer. In that case we may recommend stripping to the deck, fitting a warm roof and applying the liquid system on top. Where approval applies, we deal with the paperwork; details are on the building regulations page.
Can a liquid roof go over my existing roof, and what preparation is needed?
Yes, if the existing roof is dry, firmly bonded and sitting on a sound deck. A liquid membrane is only as good as what lies beneath it, so we test the old roof before agreeing to overlay it.
At survey we check for:
- Trapped moisture: soft spots, blisters or wet insulation mean the roof should be stripped, because water sealed in will cause new blisters and decay.
- Deck condition: any sponginess or deflection needs repair first.
- Adhesion: on felt and asphalt, loose areas are cut out and patched, and the existing surface must take the primer properly.
- Falls and ponding: a coating follows the roof as it is. If water ponds now, it will pond on the new surface too unless the falls are corrected.
Preparation then follows: loose chippings removed, the surface cleaned and left to dry, blisters cut back and repaired, cracks filled, and the right primer applied. On older felt, mineral surfaces may need extra cleaning to give a good bond. Where the tests fail, we say so plainly and quote for a strip and re-roof. Read more on ponding water.
Which towns in Dorset do we cover?
Liquid-applied 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 liquid-applied roof cost in Dorset?
£2,100–£3,350 for a typical 18 m² garage roof in a liquid-applied system, at South West guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Which council handles building control for a flat roof in Dorset?
It depends on where the roof is: in Dorset that's BCP Council and Dorset Council. 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. We confirm which applies at the survey.
Does a liquid roof smell when it is applied?
Some systems, particularly PMMA, have a strong odour during application, while many polyurethane and water-based products are milder. We tell you what to expect and plan around windows and vents.
Is liquid roofing good for balconies?
Often, yes. It forms neatly around railings, door thresholds and drains, and some systems take foot traffic. A new balcony or roof terrace generally needs planning permission, so check before converting a roof.
Can liquid roofing stop a leak on a flat roof?
It can, if the leak is at a detail or the membrane is worn but the roof beneath is sound. If water has soaked the insulation or deck, coating over it will not cure the problem.
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