What a Warm Roof Is, and What One Costs
Warm roof describes where the insulation sits, not what the roof is made of. It is used in this trade as a brand word, a finish word and a construction word, often on the same page, and the price follows the system rather than the label. Here is the distinction, the fitted bands for each named system, and the one thing no manufacturer in this market will publish. Start from the roof covering you have now.
Guardian Warm Roof · existing conservatory · fitted, all sizes
£6,980 to £14,500 typically £9,000 to £11,500
Reasonably evidenced2 third-party publishers · ~3× across the market · the manufacturer publishes nothing · checked 20 August 2026
Cosy roof for conservatory: what the phrase actually means
Cosy roof, warm roof and thermal roof are the same sales idea worded three ways: an insulated replacement roof that makes the room usable in January and July. The words are not interchangeable in building physics, but they are used interchangeably in this market, and knowing which is which is what stops you comparing two quotes that are not for the same thing.
A warm roof, strictly, is one where the insulation sits above the structural rafters, so the structure stays inside the thermal envelope and stays at close to room temperature. A cold roof puts the insulation at ceiling level, leaving the structure outside the warm zone. We flag one honest limit here: we have not found a published, conservatory-specific definition from a standards body that settles the term for this product category, and the trade uses solid, tiled, warm and insulated as synonyms when they are not. Treat the word as a prompt to ask where the insulation goes, not as a specification.
Two practical consequences. First, “Guardian Warm Roof” is a brand name that uses the term loosely, so seeing it on a quote tells you the maker and not the build-up. Second, a warm roof is not the same product as insulating the roof you already have, which is cheaper, does not reach the same U-value and does not make the room a habitable one. If you want a figure for your own conservatory first, price your conservatory roof, then read on for what the number should include.
What warm actually has to mean
There is a number behind the adjective, and it is the reason every current system quotes almost exactly the same figure.
Across the eight named systems in our register the published U-value range is 0.10 to 0.18 W/m²K, a 1.8× spread, which we grade Well evidenced because it is drawn from manufacturer technical literature across eight products. Checked 20 August 2026. The clustering is not a coincidence: 0.15 W/m²K is the limiting value a replacement roof has to meet in England, so it is the entry ticket rather than a performance claim. One manufacturer's own 2025 brochure states the requirement as 0.15 in England, 0.13 in Wales and 0.12 in Scotland. The regulation itself is set out at the U-value it has to hit.
Two figures in that range deserve a second look. The best claimed number in the market, 0.10, is published as “as low as” with no build-up behind it, so we attribute it rather than assert it. And Guardian's published maximum of 0.18 does not meet the England limiting value at all. That is a legacy figure, published against a build-up of 40mm phenolic between the rafters, 25mm between the battens and 60mm of insulated plasterboard, and it is a fair question to put to anyone quoting that system today.
Ask for the calculated U-value, in writing
A system U-value is a laboratory figure for a build-up. Your roof is that build-up minus whatever was value-engineered out of it on the day. The document that matters is the calculated U-value for the roof as quoted, with the insulation thicknesses listed. If an installer cannot produce one, the number in the brochure is not a number about your house.
What it costs fitted
Fitted prices for these systems exist only because third parties publish them. Every band below is somebody pricing somebody else's product, and we say so on every row rather than presenting it as a manufacturer figure.
| System | Low | Typical | High | Evidence |
|---|---|---|---|---|
| Guardian Warm Roof, fitted, all sizes | £6,980 | £9,000 to £11,500 | £14,500 | Reasonably |
| Ultraframe LivinROOF, fitted | £9,500 | £10,500 to £12,500 | £15,500 | Thin |
| Equinox, fitted | £8,500 | £9,500 to £11,500 | £13,500 | Thin |
| Leka, installer-quoted | £4,100 | no defensible typical | £12,000 | Reasonably |
| Guardian, installation labour only | £1,340 | not published | £2,400 | Thin, undated |
Guardian: one UK cost publisher, May 2026, for the outer band and a second, undated, for the size table, two publishers, third-party figures across the market spanning about 3×. LivinROOF: one publisher, May 2026. Equinox: one publisher, May 2026; Eurocell's own pricing returned HTTP 403 to automated fetching and is unverified. Leka: a manufacturer “from £5,500” with no date, against two installer sites at £4,100 and £12,000, 2.9× apart, so no typical is published. All checked 20 August 2026.
| Guardian by size, fitted inc VAT | Published figure | Evidence |
|---|---|---|
| Lean-to, 3m × 3m | £7,725 | Thin, undated |
| Victorian, Edwardian or gable, 4m × 4m | £8,850 | Thin, undated |
| P-shape or T-shape, 5m × 3m | £8,950 | Thin, undated |
| 5m × 5m | £10,700 | Thin, undated |
One publisher, carrying no date. It is the only source publishing a full size table for this system, which is why we show it, and the two caveats travel with it wherever it appears. The 3m by 3m figure is itemised as roof £6,150 plus fitting £1,575. Checked 20 August 2026.
Held against the general market, these land where you would expect. A tiled or solid roof on a 3m by 3m conservatory runs £6,000 to £11,000 installed including VAT, typically £8,075, which is Well evidenced across four publishers whose floors agree within 1.05×, checked 20 August 2026. A warm roof is priced like a tiled roof because, on most of these systems, it is one. The full picture on the cost of replacing the roof, or ask for conservatory roof quotes against your own size.
Which systems call themselves warm roofs
Six names cover most of the UK market, they are not the same construction, and one of them is not a roof.
- Guardian Warm Roof, made by Guardian Building Products Ltd, company 08135674. Aluminium rafter profile, phenolic insulation, 12mm ply and tiles. The only system with the words in its name.
- Ultraframe UltraRoof380, a hybrid tiled roof with optional glass, box eaves beam, SIP panels and polypropylene slates. 38 kg/m².
- Ultraframe LivinROOF, a hybrid of solid panels and glazed panels in one roof. 31 kg/m².
- SupaLite, an aluminium sub-frame with EPS between the rafters plus PIR and insulated plasterboard.
- Equinox, from Eurocell. Aluminium, pitches from 5 to 35 degrees, GRP sheet tiles or composite slate.
- Leka, the only system here with GRP rather than aluminium rafters. Reported as being in administration in several places; Companies House shows LEKA SYSTEMS LIMITED, company 09504332, active with no insolvency filings.
Ultraframe Loggia appears in most comparison articles as a seventh warm roof system. It is an insulated structural column system, and its published 0.15 W/m²K is a column figure rather than a roof figure. Ultraframe Classic appears as an eighth. It is a glazed aluminium roof; BBA 96/3261 lists its glazing as sevenwall polycarbonate or a low-E argon sealed unit. Neither belongs on this list. Side by side, with U-values and certification, they are the named warm roof systems compared, and the one that gave the category its name is set out at Guardian Warm Roof.
The refusal that explains the whole market
We checked the price pages of the three largest system makers. All either return 404 or are parked, and one of the domains is listed for sale rather than being a live brand site. One installer network states the position outright: “Rather than publishing fixed price brackets that may not reflect structural realities, a tailored survey ensures transparency and suitability.” That is a defensible position and it is also why every price on this page comes from somebody else. Retrieved and checked 20 August 2026.
One phrase we will not print about any of them is that a system is LABC approved. Every publicly downloadable certificate we located in this category is expired on its face: Guardian EW320 to 8 August 2016, SupaLite EW277 to 26 June 2016, Equinox EW606 to 19 July 2017. The current approvals we could date are 12-month Stroma Building Control certificates. Ask for a number and a validity window. You can also compare local conservatory roof installers on what they are willing to put in writing.
Weight on the existing frame
A warm roof is heavier than the polycarbonate or glass it replaces, and lighter than most people fear. LABC's addendum on solid roofs to conservatories, May 2018, puts the added load from a lightweight composite roof at approximately 0.5 kN/m, less than 10 per cent over a typical translucent roof, and says that in most cases a 150mm concrete strip foundation or a reinforced slab bearing onto original ground is adequate. The two systems in this market that publish a weight sit at 31 to 38 kg/m², Reasonably evidenced, checked 20 August 2026.
The question that actually decides the job is whether your mullions contain steel reinforcement, because frames built for a polycarbonate roof may have been reinforced only for that lighter load. A magnet test or a pilot hole answers it and nothing else does. Where the steel is not there, the fix runs £800 to £4,000, Reasonably evidenced and conflicted: one publisher puts it at £800 to £2,500, which reads as reinforcing the existing frames, and another at £3,000 to £4,000, which reads as replacing them. We attach no probability, because none is published. The survey method is set out at what your existing frame can carry.
Who signs it off
A warm roof stops the structure being an exempt conservatory, which makes the work notifiable. It goes to Local Authority Building Control or a Registered Building Control Approver, and no competent person scheme covers it. CERTASS CQ-Assured does cover warm roofs, but it issues a Certificate of Conformity rather than a Building Regulations Compliance Certificate and does not notify your local authority, so it is not a substitute. The full position is why FENSA cannot sign this off.
Budget for the fee as a separate line. Building control approval on a solid roof conversion runs £200 to £800, Reasonably evidenced and conflicted: two publishers sit 2.0× apart on the floor, most likely because one prices the application and the other the application plus the inspection regime. That is our reading rather than a published fact. Checked 20 August 2026.
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The nearest alternative, and what it changes
Most of the systems on this page produce an opaque roof, and most of the money is in the opacity rather than the word on the brochure. If what you are weighing up is the daylight you lose against the room you gain, that argument, with the same size bands and the same sources, is at what a solid roof adds and saves.
If the budget is the problem rather than the roof, insulating the roof you already have is the cheaper route and it is a genuinely different product: it does not reach 0.15 W/m²K, it does not make the room habitable in regulatory terms, and it does not need signing off in the same way. Whichever direction you go, our conservatory cost calculator shows the register rows behind the estimate rather than a single number.
Questions people ask first
Is a warm roof for a conservatory worth it?
What is the difference between a warm roof and a cold roof?
How much is a warm roof on a 3m by 3m conservatory?
Do warm roof systems meet building regulations?
Can the installer sign the work off themselves?
Why does nobody publish a price for these systems?
Every figure on this page was last checked 20 August 2026, next check due 20 November 2026. Rows graded Thin come from a single publisher; rows marked undated carry no publication date at source and we show that rather than assuming currency. Structural facts come from the LABC addendum on solid roofs to conservatories, May 2018. Company numbers are from Companies House.
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