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Green and sedum roofs across Pembrokeshire

If you are planning an extension or replacing a flat roof in Pembrokeshire, 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
£4,050–£7,450
Survey
Free for new and replacement roofs
Quote
Fixed, in writing
Coverage
England, Wales, Scotland, NI

Pembrokeshire at a glance

Largest towns
Haverfordwest, Milford Haven, Pembroke Dock, Pembroke
Postcode areas
SA
Building control
Pembrokeshire County Council
Neighbouring areas
Carmarthenshire · Swansea · Neath Port Talbot · Bridgend
Guide price region
Wales (−8% on West Midlands rates)

How much does a green roof cost in Pembrokeshire?

Guide prices including VAT at Wales 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£4,050–£7,450
Extension (20 m²), EPDM, new deck + insulation£2,600–£4,500

Which flat roofs are common in Pembrokeshire?

Flat roofs in Pembrokeshire sit on shops with flat-roofed rear stores below flats, terraced streets with flat-roofed rear kitchens and bathrooms and 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. 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 Pembrokeshire the application goes to Pembrokeshire County Council. More on the rules.

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.

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.

Which towns in Pembrokeshire do we cover?

Green and sedum roofs in Pembrokeshire: questions

Which towns in Pembrokeshire do you cover?

All of Pembrokeshire. 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 Pembrokeshire?

£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 council handles building control for a flat roof in Pembrokeshire?

It depends on where the roof is: in Pembrokeshire that's Pembrokeshire County Council. 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. We confirm which applies at the survey.

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.

Can I walk on a green roof?

Only for maintenance, and only where it is safe. Most extensive green roofs on homes aren't designed as roof terraces, and a terrace generally needs planning permission and edge protection.

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.

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

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