Plymstock at a glance
- Postcode districts
- PL9
- Population
- about 24,103 (GeoNames)
- Council area
- Plymouth City Council
- Building approval
- Plymouth City Council building control, or a registered building control approver
- Nearest main town
- Plymouth, about 2 miles
- Guide price region
- South West (+3% on West Midlands rates)
Why choose a green roof in Plymstock?
Garden rooms and outbuildings in Plymstock, as elsewhere, often have small flat roofs that are seen from the house and garden. A sedum finish helps them blend in, provided the structure is strong enough and the roof underneath is built properly.
In and around Plymstock, flat roofs are typically found on 1930s semis with flat-roofed garages and kitchen extensions, and on shops with flat-roofed rear stores below 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.
How much does a green roof cost in Plymstock?
At South West guide rates, a 20 m² insulated extension roof finished as a sedum green roof comes to £4,550–£8,350 including VAT. 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 | £4,550–£8,350 |
| Extension (20 m²), EPDM, new deck + insulation | £2,900–£5,050 |
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.
What's included?
- Drainage layer, filter and lightweight growing medium
- Root-resistant membrane or separate root barrier
- Structural check of joists, deck and supports
- Warm or inverted build-up to suit the roof
Building regulations in England
Replacing more than half of a flat roof over a heated room usually counts as renovating a thermal element, so the roof is insulated to around 0.16 W/m²K where that's technically and economically feasible, and the work is notified to building control: the council or a registered building control approver, unless a registered competent person self-certifies it. A roof on a new extension is built to 0.15 W/m²K. Patch repairs, and most unheated detached garages, don't trigger the upgrade. Structural changes, or a new covering that adds 15% or more to the roof's weight, also need approval. More on the rules.
Which nearby areas do we also cover?
Green and sedum roofs in Plymstock: questions
Do you cover Plymstock?
Yes. Plymstock is part of our Devon coverage, including postcode districts PL9. 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 Plymstock?
Where the work needs approval it goes to Plymouth City 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 Plymstock?
£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.
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 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.