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Green and sedum roofs across Gloucestershire

If you are planning an extension or replacing a flat roof in Gloucestershire, a sedum roof is worth considering. We explain the weight, building control and planning points, the root barrier and drainage, and the simple yearly maintenance, so you can decide whether it suits your roof and your budget before you commit.

Sedum green roof with a gravel border and inspection chamber on a single-storey extensionComputer-generated example image
Guide price
£4,550–£8,350
Survey
Free for new and replacement roofs
Quote
Fixed, in writing
Coverage
England, Wales, Scotland, NI

Gloucestershire at a glance

Largest towns
Gloucester, Cheltenham, Stroud, Kingswood
Postcode areas
BS, GL
Building control
Gloucester City Council, Cheltenham Borough Council, Stroud District Council and 3 other councils
Neighbouring areas
Bristol · Wiltshire · Herefordshire · Somerset
Guide price region
South West (+3% on West Midlands rates)

How much does a green roof cost in Gloucestershire?

Guide prices including VAT at South West rates. The fixed price comes after a free survey for new and replacement roofs.

JobGuide price inc VAT
Extension (20 m²), EPDM with sedum green roof£4,550–£8,350
Extension (20 m²), EPDM, new deck + insulation£2,900–£5,050

Which flat roofs are common in Gloucestershire?

Flat roofs in Gloucestershire sit on bungalows with flat-roofed side extensions and dormers, shops with flat-roofed rear stores below flats and 1960s and 1970s link-detached houses with flat-roofed garages and porches. 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 Gloucestershire the application goes to Gloucester City Council, Cheltenham Borough Council, Stroud District Council and 3 other councils. More on the rules.

How long does a green roof last and how much maintenance does it need?

A well-built extensive green roof needs one or two maintenance visits a year, and the plant layer can help protect the membrane from sunlight and temperature swings.

Typical maintenance means pulling out weeds and tree seedlings before they root, clearing outlets and the gravel strips around edges, filling in any bare patches, and adding a slow-release feed if the sedum looks thin. Sedum is drought-tolerant once established, but newly laid blankets may need watering in a long dry spell during the first season.

The waterproofing underneath has the same expected life as on any other roof of that system. A green roof also slows down rainwater run-off from the roof and, when sedum flowers, attracts bees and other insects. Some councils encourage green roofs for those reasons, so it is worth mentioning one in a planning application for a new extension. Our maintenance guide covers routine checks.

Can a green roof go on my existing flat roof?

Only if the existing waterproofing is sound, root-resistant or protected by a root barrier, and has plenty of life left. In most cases it makes more sense to lay a green roof as part of a replacement.

Once the sedum, substrate and drainage layers are down, the membrane underneath is hard to inspect and expensive to repair, because the green layers have to be lifted to get to it. Putting a green roof on an ageing covering risks paying for the greenery twice. Our repair or replace guide helps you judge whether your current roof is a sensible base.

As for planning, re-covering a house roof normally needs no application if its appearance doesn't change materially. Because a green roof does change how a roof looks, check with your council, especially for listed buildings, conservation areas and roofs that are easily seen. The planning guide has more.

Which towns in Gloucestershire do we cover?

Green and sedum roofs in Gloucestershire: questions

Which towns in Gloucestershire do you cover?

All of Gloucestershire. 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 green roof cost in Gloucestershire?

£4,550–£8,350 for a 20 m² insulated extension roof finished as a sedum green roof, 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 Gloucestershire?

All of Gloucestershire, including the BS, GL postcode areas. Send your full postcode and we'll confirm.

Can you put a green roof on a pitched roof?

We install green roofs on flat roofs only. Sloping green roofs need extra restraint to stop the growing medium slipping, and they are a specialist job outside our work.

Can a green roof have a rooflight in it?

Yes. The rooflight sits on a raised upstand with a gravel strip around it, so the planting stays clear of the glazing and the upstand stays visible and dry.

Can you put a sedum roof on a garage?

Often, yes, if the structure is strong enough. Many older garage roofs have light timbers, so a structural check comes first and strengthening may be needed.

Everything about green and sedum roofs → · All flat roofing in Gloucestershire →

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