A conservatory in 2026 typically costs £8,000–£16,000 for a straightforward lean-to, the cheapest and quickest option because its single-pitch roof sits directly against the existing house wall; £13,000–£22,000 for a Victorian or Edwardian, the most popular styles, with a bay-fronted or square footprint and more glazing and joinery than a lean-to; £20,000–£35,000 for a gable-end, which has its own vertical front wall and apex roof for extra headroom and light; and £28,000–£50,000 or more for an orangery, which uses brick piers and a flat, part-solid roof with a glazed lantern and is closer to a small extension in build method than a conservatory.
But those bands only answer "what does it cost to build" — not "will I actually use it", which in my experience is the more expensive question. A conservatory built to the building regulations exemption isn't required to meet any insulation standard at all, which is exactly why so many end up as an expensive room nobody sits in for half the year: too hot to bear in July, too cold to heat efficiently in January. That's a design and thermal-performance question as much as a budget one, and it's worth settling before you price up a style.
I'm a building surveyor and domestic energy assessor, not a conservatory installer, so what follows is 2026 pricing cross-checked against current UK cost guides, what actually drives the number, the permitted development and building regulations rules that decide what you can build without a planning application, and — because it's my own patch — how a conservatory is treated on an EPC, and the mistake that quietly wrecks that rating.
The short answer
Figures below were checked on 11 August 2026 against 2026 cost guides from Checkatrade, RatedPeople and specialist conservatory and orangery installers, cross-referenced against each other — the spread between sources is wider than most trades in this series, because so much rides on frame material, roof type and glazing spec. As with the rest of this series, London and the South East, Dom’s patch included, commonly run 20–25% above the national figures quoted here.
| Type | Typical cost (2026) | What's included |
|---|---|---|
| Lean-to | £8,000–£16,000 | Simple single-pitch roof against the house wall, cheapest and fastest to build, least floor area for the money |
| Victorian / Edwardian | £13,000–£22,000 | Bay-fronted or square footprint, the most common styles, more glazing bars and joinery than a lean-to |
| Gable-end | £20,000–£35,000 | Vertical front wall with its own apex roof, more headroom and light, a more complex roof structure to build |
| Orangery | £28,000–£50,000+ | Brick piers, flat perimeter roof with a glazed lantern, nearer a small extension in cost and build method |
Per square metre, that works out at roughly £1,500–£3,000/m² for a glazed structure, toward the bottom for a basic polycarbonate-roofed box and above £3,000/m² for an orangery with a solid lantern roof. Fitting a solid or tiled roof to fix the comfort problem on an existing conservatory — covered further down — typically adds £6,000–£15,000 depending on size, or £2,500–£15,000 for a straight roof swap on its own.
What drives the price
Size. The per-m² rate holds roughly steady across a given style, but a staircase's worth of fixed costs — base, structural steel where needed, planning fees — don't shrink for a small room, so tiny conservatories rarely look proportionally cheap.
Frame material. uPVC is the cheapest by a clear margin; aluminium and timber both add 20–40% depending on the finish, and hardwood more again. Aluminium is increasingly the middle-ground choice because it takes slimmer sightlines and larger glazed panels than uPVC.
Roof type. A polycarbonate roof is cheapest to install but performs worst thermally; a glass roof with solar-control coating sits in the middle; a solid or tiled roof costs the most upfront but is the only one that behaves like a proper room in both summer and winter — this is the single biggest lever on both price and how much the room actually gets used.
Base and groundworks. A conservatory needs its own foundation, and a sloping site, soft ground or nearby trees on clay soil can mean a more substantial (and more expensive) base than a standard concrete raft — a check worth doing before a quote is treated as fixed.
Glazing spec. Solar control and self-cleaning glass, and double or triple glazing to a decent U-value, add cost but do most of the work in making the room usable without the roof upgrade above.
Planning route. Staying within standard permitted development limits costs nothing extra; a larger conservatory needing prior approval under the Neighbour Consultation Scheme adds a modest council fee, typically £100–£250, and a few weeks' wait.
Region. London and the South East commonly run 20–25% above the national figures quoted here, largely down to labour rates and site access in denser housing.
Permitted development — what you can build without planning permission
Most houses can add a conservatory without a planning application, provided it stays within permitted development limits: no more than 3 metres beyond the rear wall for a terraced or semi-detached house, or 4 metres for a detached house; a maximum height of 4 metres overall, reduced to 3 metres where the structure sits within 2 metres of a boundary; and eaves no higher than the existing house eaves. A side conservatory is capped at half the width of the original house and, on designated land such as a conservation area, can't extend beyond the side walls at all. Combined with any other extension or outbuilding already built, the total can't cover more than 50% of the garden around the original house — that limit is cumulative for the life of the building, so a previous extension eats into what's left.
A larger conservatory — up to 6 metres for a terraced or semi-detached house, or 8 metres for a detached house — can still avoid a full planning application under the Neighbour Consultation Scheme, which involves submitting a prior approval application, a modest council fee, and a 21-day notice period to adjoining neighbours. If no neighbour objects, or the council doesn't intervene, the scheme is deemed approved without a full application. Flats and maisonettes have no permitted development rights for conservatories at all and always need planning permission, and an Article 4 direction — common in some conservation areas — can remove permitted development rights for a house too, so it's worth a quick check with the local planning authority before a design is drawn up.
The heat problem — thermal performance and the EPC trap
Here's the detail that decides whether a conservatory earns its keep: it's normally exempt from the building regulations entirely, provided it's at ground level, under 30 square metres of internal floor area, and thermally separated from the house by an external-quality wall, door or window. That exemption means nobody has to meet any insulation standard on the walls, roof or glazing — which is exactly why so many conservatories are unbearable in summer and need supplementary heating all winter, whatever was spent building them. A polycarbonate or single-glazed lean-to bought on price alone is the classic result.
The separating door is doing more work than it looks like. Swap it for a wide opening, bi-fold doors left permanently open, or knock the wall through entirely to make the conservatory feel like part of the kitchen or living room — an increasingly popular renovation move — and the whole combined space technically has to comply with the full building regulations, including Part L insulation standards that a conservatory built to the exemption was never designed to meet. That's an expensive retrofit to do properly after the fact, not before.
It also has a direct, and often unexpected, consequence for the EPC. Under RdSAP, the assessment method behind every domestic EPC, a conservatory is defined by how much of it is glazed — broadly, 50% or more of its external walls and 75% or more of its roof — and a thermally separated one meeting that definition is excluded entirely from the calculation. It doesn't count toward the floor area or the heat loss figure, so it neither helps nor harms the rating while the separating door stays in place. Remove that door, and the assessor has no choice but to bring the whole space into the calculation, complete with whatever glazing and roof it was actually built with. I've seen that single change drag a rating down a full band or more on a re-assessment, which matters more than it sounds: landlords need an E or above to legally let a property under MEES, and a slipping band can affect mortgage terms too. Worth knowing before "let's open this up" becomes the plan, and worth an EPC check before, not after, if you're planning to sell or let.
What I'd watch for in a quote
- Base and foundation type specified for your actual ground conditions, not a standard raft assumed regardless of slope or soil — priced in, not discovered once digging starts.
- Roof type and its U-value stated plainly (polycarbonate, glass or solid/tiled), not just described as "high performance" without a figure.
- The separating door confirmed as external-quality and staying in place, if keeping the building regulations exemption and an unaffected EPC matters to you.
- Planning route confirmed in writing — permitted development, Neighbour Consultation Scheme, or full planning — not left for you to discover from a neighbour's objection.
- Electrics, and any heating, scoped explicitly, since retrofitting either into a finished conservatory later is disruptive and priced high.
Questions I get asked
Does a conservatory need planning permission? Usually not, provided it stays within permitted development limits: extending no more than 3 metres beyond the rear wall for a terraced or semi-detached house (4 metres for a detached house), a maximum height of 4 metres (3 metres within 2 metres of a boundary), and not covering more than 50% of the garden once every other extension and outbuilding is counted in. A larger conservatory, up to 6 metres or 8 metres respectively, can still avoid a full application under the Neighbour Consultation Scheme, which involves a modest council fee and a 21-day notice period to adjoining neighbours. Flats and maisonettes have no permitted development rights and always need planning permission, and a conservation area or Article 4 direction can remove the rights for a house too.
Does a conservatory need building regulations approval? Most don't, because a conservatory is normally exempt from the building regulations provided it's at ground level, under 30 square metres of internal floor area, and thermally separated from the house by an external-quality wall, door or window. That separating door is doing real work: remove it, or swap it for a wide opening, and the whole combined space technically has to comply with the full building regulations, including Part L insulation standards that most conservatories were never built to meet.
Does a conservatory affect my EPC rating? A thermally separated conservatory is excluded entirely from an EPC assessment under RdSAP, the method behind every domestic EPC — it doesn't count toward the floor area or heat loss calculation, so it neither helps nor harms the rating while the separating door stays in place. Remove that door to open the conservatory into the house and the assessor has to bring the whole space into the calculation, including its usually poor-performing glazing and roof. That single change routinely drags a rating down a full band or more, which matters if you're selling, remortgaging, or letting the property, where landlords need an E or above.
Does a conservatory add value to a house? Estimates vary: RICS puts the typical uplift around 5%, Checkatrade around 7%, and Savills suggests up to 10% for a well-specified example — all well below the 15–20%+ a genuine loft conversion or extension can add. Condition does most of the work in that range: a well-insulated, well-maintained conservatory in proportion to the house adds toward the top of it, while a dated, draughty or leaking one that a surveyor flags for damp, blown units or roof movement is routinely treated as a liability rather than an asset, sometimes value-neutral or worse.
If you're weighing up a new conservatory, a solid-roof upgrade to an existing one, or knocking through to open it into the house, the question worth answering first is what it does to your EPC and whether building control still sees it as exempt — that's exactly the kind of check my EPC assessments and building survey work are built around. Call 07946 618203 or get in touch for a straight answer before you commit to a design.
Small print. This guide is general information, not advice on a specific property, and it doesn’t replace a proper inspection and quote for your own home. Prices were researched and correct to the best of my knowledge on 11 August 2026; costs move and vary by region and property. Always get at least three written quotes.