- Guide price
- £4,200–£7,700
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
West Dunbartonshire at a glance
- Largest towns
- Clydebank, Vale of Leven, Dumbarton, Duntocher
- Postcode areas
- G
- Building standards
- West Dunbartonshire Council
- Neighbouring areas
- Renfrewshire · East Dunbartonshire · Inverclyde · Glasgow City
- Guide price region
- Scotland (−5% on West Midlands rates)
How much does a green roof cost in West Dunbartonshire?
Guide prices including VAT at Scotland 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 | £4,200–£7,700 |
| Extension (20 m²), EPDM, new deck + insulation | £2,650–£4,650 |
Which flat roofs are common in West Dunbartonshire?
Flat roofs in West Dunbartonshire sit on 1960s and 1970s link-detached houses with flat-roofed garages and porches, low-rise post-war blocks of flats and terraced streets with flat-roofed rear kitchens and bathrooms. Scotland averages roughly 1,570 mm of rain a year, with the west far wetter than the east, so drainage, falls and wind uplift are part of every specification we write. Approximate 1991–2020 regional averages based on Met Office data.
Building standards in Scotland
In Scotland a building warrant is usually needed for alterations, structural work and new roofs; like-for-like repairs to a covering can be exempt. Section 6 of the technical handbooks sets a domestic roof benchmark of 0.12 W/m²K, applied as far as reasonably practicable on an existing roof. In West Dunbartonshire the application goes to West Dunbartonshire Council (building standards). More on the rules.
How is a green roof built on top of a flat roof?
From the bottom up, a green roof is a deck, a waterproofing system with root protection, then drainage, filter, growing medium and plants. The waterproofing does the job of keeping water out. The green layers sit above it.
- Warm roof build-up: vapour control layer, insulation and waterproof membrane on the deck, then the green layers on top. This is the usual choice on a home extension being re-roofed.
- Inverted build-up: waterproofing on the deck, then insulation boards designed to sit above it, then the green layers. This is common on terraces and some commercial roofs.
- Root barrier: roots will exploit any weakness, so the membrane needs to be root-resistant. Some membranes are tested as root-resistant; others need a separate root barrier laid on top.
- Drainage and edges: a drainage layer carries surplus water to outlets, and a gravel or pebble strip is usually left around edges, outlets, upstands and rooflights to keep them clear and accessible.
Upstands still need to rise around 150 mm above the finished surface, which on a green roof means above the top of the growing medium. We check that at the survey, alongside the external fire performance of the build-up where the roof is close to a boundary.
Which towns in West Dunbartonshire do we cover?
Green and sedum roofs in West Dunbartonshire: questions
Which towns in West Dunbartonshire do you cover?
All of West Dunbartonshire. 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 West Dunbartonshire?
£4,200–£7,700 for a 20 m² insulated extension roof finished as a sedum green roof, at Scotland guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Which council handles building standards for a flat roof in West Dunbartonshire?
It depends on where the roof is: in West Dunbartonshire that's West Dunbartonshire Council. In Scotland a building warrant is usually needed for alterations, structural work and new roofs; like-for-like repairs to a covering can be exempt. 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.
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.
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 West Dunbartonshire →