- Guide price
- £4,050–£7,450
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
Carmarthenshire at a glance
- Largest towns
- Llanelli, Ammanford, Carmarthen, Burry Port
- Postcode areas
- SA
- Building control
- Carmarthenshire County Council
- Neighbouring areas
- Swansea · Neath Port Talbot · Bridgend · Rhondda Cynon Taf
- Guide price region
- Wales (−8% on West Midlands rates)
How much does a green roof cost in Carmarthenshire?
Guide prices including VAT at Wales rates. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Extension (20 m²), EPDM with sedum green roof | £4,050–£7,450 |
| Extension (20 m²), EPDM, new deck + insulation | £2,600–£4,500 |
Which flat roofs are common in Carmarthenshire?
Flat roofs in Carmarthenshire sit on newer estates where the first extension roofs are now being replaced, terraced streets with flat-roofed rear kitchens and bathrooms and 1960s and 1970s link-detached houses with flat-roofed garages and porches. Wales averages roughly 1,460 mm of rain a year, among the wettest in Britain, so we design for steady run-off: proper falls, clear outlets and upstands well above the finished roof. Approximate 1991–2020 regional averages based on Met Office data.
Building regulations in Wales
Welsh guidance is that most re-roofing needs building control approval, so it's worth checking whenever more than a quarter of a roof is replaced or repaired. Renovated roofs are upgraded to around 0.16 W/m²K where feasible, and new extension roofs are built to 0.13 W/m²K under the Welsh Approved Document L. In Carmarthenshire the application goes to Carmarthenshire County Council. More on the rules.
Can my flat roof take the weight of a green roof?
Not every roof can, which is why we check the structure before quoting. A sedum roof is light compared with an intensive garden, but its growing medium holds water, and a saturated build-up adds significant weight to the roof.
We look at the joist sizes, spans and spacing, the condition of the deck and what the roof sits on. On a recently built extension with generously sized joists, an extensive green roof may be straightforward. On an older garage or a roof with undersized or rotten timbers, the structure may need strengthening, or a structural engineer's calculation may be needed before we can go ahead.
In England, a new roof covering that adds 15% or more to the weight of the roof triggers building control approval, and a green roof will often fall into that category. We handle building control where it is needed. The building regulations page covers the approval routes in each nation.
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.
Which towns in Carmarthenshire do we cover?
Green and sedum roofs in Carmarthenshire: questions
Which towns in Carmarthenshire do you cover?
All of Carmarthenshire. 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 Carmarthenshire?
£4,050–£7,450 for a 20 m² insulated extension roof finished as a sedum green roof, at Wales guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Which postcode areas do you cover in Carmarthenshire?
All of Carmarthenshire, including the SA postcode areas. Send your full postcode and we'll confirm.
Does a green roof leak more than a normal flat roof?
No, as long as it is built correctly. The waterproofing beneath is what keeps water out, and the green layers protect it from sun and weather. The main risk is building it on a weak or ageing membrane.
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.
What happens if a green roof needs repairing?
The green layers are lifted around the problem area, the membrane is repaired, and the layers are relaid. Building on a sound, long-life membrane in the first place keeps that to a minimum.
Everything about green and sedum roofs → · All flat roofing in Carmarthenshire →