Conservatory Conversion: Turning an Old Conservatory Into a Room You Use

A conservatory conversion turns a conservatory that is too hot, too cold or too flimsy to use into a room that works all year. There are four routes: change the roof, upgrade the glazing and heating, open the room to the house, or take it down and replace it with an orangery or winter garden on the same footprint. Which one is right depends on what the existing conservatory was built on, and on what you want the room to be.

What does a conservatory conversion involve?

At its simplest, a new roof; at its most complete, a new room. Every conversion starts with the same three checks. What is the base built on, and is it sound? Can the frames carry a different roof? And is the room the right size and in the right place for what you want it to become? A conservatory that fails the first two is a candidate for replacement, not conversion, however new the roof would look.

Can you change the roof on a conservatory?

Yes, and it is the conversion most people mean. There are three routes:

• Solid tiled roof: an insulated, lightweight tiled roof with a plastered ceiling inside. It gives the warmest, quietest room, but the darkest, and it usually needs rooflights or a lantern to keep the light.

• Hybrid roof: a solid insulated roof with glazed panels or a lantern set into it, trading some warmth for light.

• Glass roof: modern solar control glass in place of old polycarbonate. The room stays a conservatory, gains light and quiet, and becomes far more comfortable in summer.

The limit is structure. A solid roof weighs considerably more than the glazed roof it replaces, and standard frames on a light base were not designed for it. The load usually has to be carried on a ring beam, a structural beam around the top of the frames or walls that spreads the roof weight down to the base, and the frames and foundations have to be checked to confirm they can take it. Where they cannot, the honest advice is a new room rather than a new roof on an old one.

A solid or tiled roof generally needs building regulations approval, so building control inspects the work and issues a completion certificate at the end. The roof swap itself is typically a matter of days to a couple of weeks on site, once the structural check, design and approval are in place. What drives the cost of each route is explained in our conservatory roof replacement cost guide.

Can you upgrade the glazing and heating instead?

Often, and it is the least disruptive route. Replacing old double-glazed units with modern solar control glass on the roof and low-emissivity glass on the walls changes how the room feels in July and January without touching the structure. Adding underfloor heating on a properly insulated floor, or a dedicated heating circuit with its own controls, does the rest. Roof blinds and vents finish the job.

This route works when the frames and base are sound and the room is simply under-specified. It does not work when the base is thin and the floor is cold from below; there the floor has to come up, and at that point the conversation usually turns to replacement.

Can you convert a conservatory into an extension?

Yes, by opening it to the house. Removing the doors between house and conservatory, or replacing them with a wide structural opening, removes the building regulations exemption, so the floor, roof and glazing must then meet extension standards and the work needs approval. On a light conservatory that means rebuilding most of it anyway. Our post on when a conservatory becomes an extension explains where the line falls. Our luxury conservatories are specified as separate garden rooms or as open-plan extensions from the outset.

When is replacement better than conversion?

When the base is inadequate, when the frames are standard and cannot take a better roof, when the room is the wrong shape for its new purpose, or when the sum of the upgrades approaches the cost of a new room. A replacement also lets you change the type: a conservatory that was always too cold becomes an orangery with brick piers, an insulated roof and a lantern, and our guide to how you convert a conservatory to an orangery walks through what that involves. A conservatory that was always too hot becomes a modern winter garden conservatory in slim aluminium with insulated glazing throughout.

The advantage of replacement is that every part of the room is designed for the way you will use it, rather than adapted from a room designed for something else.

What about planning and building regulations for a conversion?

Planning is rarely an issue for a like-for-like roof change or a glazing upgrade. A replacement on a larger footprint, or on a listed building or in a conservation area, is checked against the usual rules, and the current position is set out on the Planning Portal.

Building regulations depend on the route. A glass-for-glass roof swap on a closed-off conservatory usually stays within the exemption. A solid roof, an opening to the house, or heating connected to the house system each take the room out of the exemption and require approval. A conversion that ends with a completion certificate is worth more at sale than one that does not.

Conservatory conversion questions, answered

How much does a conservatory conversion cost?

It ranges from a glazing upgrade at the lower end to a full replacement at the upper end, with a new roof in between. Our conservatory roof replacement cost guide explains what drives the cost of each roof route; a replacement is priced as a new conservatory or orangery.

Can any conservatory be converted?

Any conservatory can be improved. Not every conservatory can carry a solid roof or be opened to the house without rebuilding, which is why the structural check comes first.

Is it cheaper to convert a conservatory or replace it?

A conversion is cheaper when the base and frames are good. When they are not, a conversion can cost most of a replacement and deliver less. An honest survey tells you which you have.

Talk to our design team

The best conservatory conversion is the one that starts with a clear view of what is worth keeping. If you have a conservatory you would like to use again, talk to us about your project and we will tell you whether to convert it or start again.