Treharris at a glance
- Postcode districts
- CF46
- Population
- about 12,352 (GeoNames)
- Council area
- Merthyr Tydfil County Borough Council
- Building approval
- Merthyr Tydfil County Borough Council building control, or a registered building control approver
- Nearest main town
- Rhondda, about 6 miles
- Guide price region
- Wales (−8% on West Midlands rates)
Why choose a green roof in Treharris?
If you're replacing an old flat roof in Treharris, it's worth deciding whether to add sedum at the same time. If the structure can take it, that is the ideal moment, because the waterproofing is new and the green layers won't need lifting for a long time.
In and around Treharris, flat roofs are typically found on low-rise post-war blocks of flats, and on newer estates where the first extension roofs are now being replaced. 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.
How much does a green roof cost in Treharris?
For Treharris we use Wales rates: £4,050–£7,450 is the guide for a 20 m² insulated extension roof finished as a sedum green roof, VAT included. 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 |
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.
What's included?
- Drainage layer, filter and lightweight growing medium
- Root-resistant membrane or separate root barrier
- Structural check of joists, deck and supports
- Pre-grown sedum blankets laid and watered in
Building regulations in Wales
The Welsh Approved Document L applies. Renovating more than half of a roof over a heated room means upgrading it to around 0.16 W/m²K where feasible, and new extension roofs are built to 0.13 W/m²K. Welsh Government guidance is that most re-roofing needs building control approval, so check whenever more than a quarter of a roof is replaced or repaired. We deal with the application as part of the job. More on the rules.
Which nearby areas do we also cover?
Green and sedum roofs in Treharris: questions
Do you cover Treharris?
Yes. Treharris is part of our Merthyr Tydfil coverage, including postcode districts CF46. Surveys and roofs are carried out by vetted roofing teams working under S&K Property Investments and Improvement Ltd.
Who checks building regulations for a flat roof in Treharris?
Where the work needs approval it goes to Merthyr Tydfil County Borough Council building control, or a registered building control approver. We tell you at the survey whether your job needs it and deal with the paperwork as part of the quote.
How much does a green roof cost in Treharris?
£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.
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.
Do I need to water a sedum roof?
Usually only in the first season, during long dry spells, while the blankets establish. After that, sedum copes with dry weather well.