Green Roof Cost in Sheffield & North East Derbyshire (2026)

Straight answer first: a sedum green roof costs from £285/m² inc VAT with us, and that price includes the single ply roof underneath and an electronic leak test. On a ground-floor roof that works out at:

Garden room or garden office, 10 m², with warm roof insulation: £3,250–£3,430
Single garage, about 20 m², no insulation: £5,700–£6,060
Double garage, about 30 m², no insulation: £8,550–£9,090
Extension, about 40 m², with warm roof insulation: £13,000–£13,720

Those are the figures our green roof estimator gives. Below: how they are built, what a green roof costs over a plain flat roof, and what we confirm before you get a firm price in writing.

How much does a green roof cost? Prices by size

Roof	Size	Uninsulated	Warm roof
Porch or bay	6 m²	£2,060	£2,060
Garden room	10 m²	£2,850–£3,030	£3,250–£3,430
Garden room	15 m²	£4,275–£4,545	£4,875–£5,145
Single garage	20 m²	£5,700–£6,060	£6,500–£6,860
Double garage	30 m²	£8,550–£9,090	£9,750–£10,290
Extension	40 m²	£11,400–£12,120	£13,000–£13,720

All prices are inc VAT for a ground-floor roof, with the single ply roof beneath, the sedum layer and an electronic leak test included. Use the warm roof column if the room below is heated, and the uninsulated column for an unheated garage or store. A garden room or small garden office roof is often 10–15 m², so measure yours. On the 6 m² row, our £950 minimum charge for the roofing works applies in both columns (see below).

If the roof is first floor or higher, scaffolding adds £1,000 to £2,000.

Sedum roof cost per m²: how the price is built

Per m², a sedum roof costs £285–£303 inc VAT without insulation, or £325–£343 as a warm roof. That comes from three lines, and only one of them is the sedum.

1. The single ply roof beneath: £100–£118/m². This is the waterproofing, the part that keeps the building dry, and if there is an old roof to strip off first, that is included. It is the same £100–£118/m² we charge for a plain flat roof replacement on most homes, and it carries the same cover: a 20-year manufacturer-backed warranty on the membrane plus our own 20-year workmanship guarantee.

2. The sedum layer: £185/m². The system we use is Fatra’s Modular Tray, the same as on our Sheffield garage. The trays arrive pre-grown, are laid on a protection fleece over the membrane and clip together, so the roof is green and established on day one. No seeding, no waiting. Each tray is 540 × 540 mm, made from recycled polypropylene, with 30–40 mm of plants growing in 60 mm of recycled growing medium. The tray is also the drainage layer and the water reservoir: Fatra’s figure is that it holds about 20 litres of water per m².

3. Warm roof insulation, if the room below is heated: +£40/m². A heated room under a flat roof needs a warm roof to current Building Regulations, usually to a U-value of 0.18 W/m²K. An unheated garage or store can stay a cold, uninsulated deck. The sedum is not insulation, so it does not replace this. More on warm roof upgrades.

The electronic leak test: included. On every green roof, we test the finished membrane electronically before anything goes on top of it. Once the sedum is down, a leak would be hidden under the plants, so this is the moment to find it. When we lay the membrane, the test is part of the price; testing one we didn’t lay is £500. Here is how electronic leak detection works.

Our Sheffield green roof case study shows that order of work on a real job: a warm roof on a new stone garage, tested, then finished with pre-grown Fatra Modular Trays.

The £950 minimum on small roofs

Our £950 minimum job charge covers the roofing works only: the membrane, plus insulation if you have it. The sedum is added on top.

Take a 6 m² porch or bay roof. The membrane at £100–£118/m² would come to £600–£708, which is under the minimum, so the roofing works are £950. The sedum is 6 × £185 = £1,110. Total: £2,060 inc VAT, with the leak test still included. On a roof without insulation, the minimum applies to anything under about 9.5 m².

Green roof vs a plain flat roof

Take a single garage of about 20 m², on the ground floor, with no insulation:

Plain single ply flat roof: £2,000–£2,360 inc VAT
Sedum green roof: £5,700–£6,060 inc VAT

The difference is the sedum layer: 20 m² × £185 = £3,700. The roof beneath costs the same either way.

So what does that £3,700 get you? Honestly:

A roof worth looking at. If you look down on the garage or extension from the house, you see planting instead of grey membrane. Fatra’s sedum mix has 8–12 sedum varieties. It is evergreen and the lowest-maintenance choice. Our Sheffield garage was in flower the day we finished it. Sedum also turns red or bronze in dry or cold spells or when it is short of nutrients. That is stress, not a dead roof.
Slower rainwater. Fatra’s figure is that a green roof can retain around 75% of summer rainfall runoff. One garage roof will not stop a flood, but it takes some of the load off your gutters and drains.
Possibly some help with planning. A green roof may count in a scheme’s favour on biodiversity and drainage, and some councils ask for one. There are no promises, though. Check with your local planning authority: Sheffield City Council, North East Derbyshire District Council or Chesterfield Borough Council, depending where you live. If your home is in a conservation area or inside the Peak District National Park boundary, talk to the planning authority early.

What it does not get you: it is not insulation, and the plants are living things, not a product with a 20-year warranty. It also needs a little looking after once a year. If none of the points above matter to you, a plain single ply roof is the cheaper answer, and we will say so. Our green roofs page covers the full build-up.

What changes the price

The estimator gives you a guide price. These are the things that can move it before you get a firm price in writing:

The structure. A green roof is heavy when it is wet. Fatra’s saturated weights are 65 kg/m² for sedum and 75 kg/m² for the wildflower mixes. A structural engineer confirms the structure can carry that, and we install on the basis of their calculation. Some structures need strengthening and some aren’t suitable. You arrange the engineer and pay their fee separately: it isn’t in our price, and nor is any strengthening. On a new build, your designer or structural engineer sizes the joists to the saturated load, so give them Fatra’s figures.
Access and height. First floor or higher means scaffolding, at £1,000 to £2,000. Unusual access is confirmed at the visit.
Edge details. The trays can run up to a parapet or upstand, finish at a pebble margin, or stop at an aluminium guard. We agree the edge detail for your roof at the visit.
The plant mix. The estimator prices sedum only. Sedum & wildflower adds 20–30 wildflower and meadow grass varieties and needs more maintenance. Brown wildflower has no sedum: it blooms in spring and summer and dies back to bare in autumn and winter. Both are priced at the visit.
New build or existing roof. The estimator asks which yours is. An existing flat roof usually needs a new root-resistant membrane anyway, and stripping the old roof is included. If your membrane is good enough to keep and we didn’t lay it, we test it first, and that test is £500 (see the FAQs below).

We usually visit within 2–5 working days, and the written quote follows within 2–3 working days of the visit.

Running costs: once a year, in early autumn

There is no mowing, and no watering once the plants are established, except in a long dry spell. Then Fatra suggests about an hour once a week, or you can wait for rain. Fatra’s maintenance routine is once a year in early autumn, after the bird nesting season:

hand-weed any unwanted seedlings
clear the outlets and gutters
feed with an organic phosphate and potassium fertiliser
keep the pebble margins clear of plants
clear fallen leaves

You can do that yourself, or ask us about our roof maintenance plans, which cover green roofs as well as single ply.

Where we quote for green roofs: Sheffield, Dronfield and Chesterfield

We are based in Kilnhurst, and we quote for green roofs across Sheffield, especially the western and south-western suburbs: Dore, Totley, Bradway, Fulwood, Ranmoor, Ecclesall, Whirlow, Crosspool and Broomhill (S10, S11 and S17). S10 and S11 are about 32 minutes from our yard, and S17 about 38.

We also cover the North East Derbyshire edge: Dronfield and Holmesfield (S18), Eckington (S21) and Chesterfield (S40–S45). Pricing a green roof in Chesterfield or Dronfield works the same way: the estimator first, then a free quote visit. There is no extra charge for travel.

Planning a green roof on a smaller building? Our guide to green roofs on extensions, garages and garden rooms covers the structure, edges and drainage to get right.

Get your price

Get a guide price: tell the estimator the size of the roof, how high it is and whether you want insulation, and you get a range inc VAT.
Send us your drawings: for when you already have plans from an architect or builder.

If a builder or landscaper is already on the job, we work alongside them: they build the structure and lead the garden, and we take the waterproofing, the leak test and the sedum layer.

Business clients: commercial work is quoted per job and is + VAT. Architects and main contractors, here is how we work with design teams on green roofs.

Green roof cost FAQs

Is VAT included in these prices? Yes. Every homeowner price on this page includes VAT. Commercial work is quoted per job and is + VAT.

Does the price include the roof underneath? Yes: stripping the old roof if there is one, the single ply roof beneath, the sedum layer and an electronic leak test. Warm roof insulation (+£40/m²) and scaffolding (£1,000 to £2,000) are added only if your roof needs them. The structural engineer isn’t included (you arrange them and pay their fee separately), and nor is any structural work. Unusual access, edge details and wildflower mixes are confirmed at the visit.

Can you add sedum to my existing flat roof? Sometimes. The membrane has to be root-resistant and in genuinely good condition, and the structure has to carry the saturated weight, which a structural engineer confirms. On most tired felt roofs the membrane alone rules it out, so the usual answer is a new membrane with the green roof on top. Before we quote, we will tell you whether your membrane can stay. If we keep a membrane we didn’t lay, we test it electronically before the green roof goes on, and that test is £500.

Do you charge extra for the leak test? Not when we lay the roof underneath: we test the membrane electronically before the sedum goes on, and it is included in the price. If the green roof is going on a membrane we didn’t lay, the test is £500.

How long does it take? Our Sheffield garage ran in two short visits: the waterproofing in June and the green roof in early July. Because the sedum arrives pre-grown, it was in flower the day we finished.

What warranty do I get? The membrane carries a 20-year manufacturer-backed warranty plus our 20-year workmanship guarantee. The plants are living, so they don’t carry a 20-year warranty. Fatra guarantees the trays for 1 year.

Prices correct as of October 2026, inc VAT for homeowners.