Glazed extensions cover everything from a bolt-on Victorian-style conservatory to a fully insulated garden room with its own kitchenette. In 2026, UK prices across the family run from around £8,000 for a modest lean-to conservatory to £60,000 or more for a large, high-specification garden room or orangery — with roof lanterns and rooflights sitting at the cheaper end as an upgrade to an existing extension rather than a standalone structure.
The right choice depends on how the space will be used, whether it needs to be heated and lived in year-round, and how much planning risk you’re willing to take on. This guide curates our detailed guides to each type — what they cost fully fitted, and the planning and Part L rules that apply — in one place.
Conservatories: Cost and Types
A conservatory is defined by its largely glazed roof and walls, and is usually built under permitted development provided it stays single-storey and within footprint limits. Our full breakdown of conservatory prices by style — lean-to, Victorian, Edwardian and P-shape — covers what drives the £8,000–£35,000 range and the glazing specification worth insisting on.
Older conservatories rarely perform well against modern Part L standards; if yours has a failing polycarbonate roof, conservatory refurbishment costs covers swapping it for a solid insulated roof versus a full refit. Whatever the roof, solar gain is the main comfort problem in summer — conservatory blinds and their cost compares pleated, pinoleum and perfect-fit options for heat and glare control.
Orangeries and Sunrooms
An orangery sits between a conservatory and a full extension: more brick, a flat roof with a glazed lantern, and a stronger case for year-round use at £30,000–£60,000. Our comparison of an orangery against a conservatory and a full extension sets out the cost, thermal performance and resale differences.
A sunroom takes the opposite approach — mostly glazed walls in a timber or aluminium frame, prioritising garden views over thermal mass. Our sunroom cost guide explains the gap between a prefabricated kit and a fully installed, Part-L-compliant structure.
Garden Rooms: A Detached Glazed Space
A garden room is a standalone glazed building rather than an attached extension, with different planning and value trade-offs. Our garden room cost and planning guide covers the full range from a basic insulated box to a high-specification year-round space, and garden room planning permission rules explains the Class E limits that keep most builds consent-free.
Weighing a detached garden room against extending the house itself? Garden room vs extension compares cost, added value and disruption. And if the room is destined to be a home office, garden office vs garden room covers the extra insulation, power and broadband specification that working from it daily demands.
Roof Lanterns and Rooflights
Not every glazed addition needs to be a whole new room — a roof lantern or rooflight can bring the same light into an existing flat-roof extension or loft. Our roof lantern cost guide covers sizes, frame materials and the £1,500–£8,000+ fitted range.
For the wider family of options, rooflight materials and types compares flat rooflights, pitched roof windows and lanterns on U-value and cost, and skylights vs roof lanterns vs roof windows is the quickest route to the right term for your roof shape. If the glazing is going into a loft rather than a ground-floor extension, loft conversion windows and skylights covers the fire-egress rules specific to that context.
Planning Permission, Part L and Choosing Between Them
Most conservatories, orangeries, sunrooms and garden rooms fall under permitted development if they’re single-storey and stay within the relevant footprint, height and curtilage limits. The exceptions are consistent across the family: listed buildings, Article 4 Directions, and anything that pushes total garden coverage over 50%.
Part L is the more common trip hazard than planning. A conservatory or porch under 30m² with its own external doors to the house is typically exempt from Part L, but the moment that separating door comes out — or the space is heated permanently — it must meet the same U-value and glazing standards as the rest of the house. This is the single biggest reason two “like-for-like” quotes can differ by thousands.
| Type | Typical Cost (fitted) | Planning | Best For |
|---|---|---|---|
| Conservatory | £8,000–£35,000 | Usually PD | Budget glazed space, seasonal use |
| Orangery | £30,000–£60,000 | Usually PD | Kitchen-diner feel, more solid structure |
| Sunroom | £10,000–£50,000 | Usually PD | Garden views, timber/aluminium frame |
| Garden room | £8,000–£60,000+ | Usually PD (Class E) | Detached office, studio or annexe |
| Roof lantern | £1,500–£8,000+ | Part of host extension | Adding light to an existing flat roof |
[!tip] Ask About Part L Before You Compare Quotes A conservatory quote that’s £5,000 cheaper than a rival’s is often simply excluding the insulated roof, upgraded glazing or separating door needed to meet Part L. Ask each contractor to confirm in writing whether their price is Part L compliant before comparing line by line.
Where to Start
If budget is the main constraint, start with the conservatory cost guide — still the cheapest way to add a glazed room. If you want a standalone, year-round space, the garden room cost and planning guide is the better starting point. And if you already have an extension but want more light in it, the roof lantern cost guide is the quickest, cheapest upgrade of the three.
