Converting a Conservatory to an Orangery: A Complete Guide
Updated: Oct 6
Yes, most conservatories can be converted to an orangery, provided a survey confirms the existing base and footings can carry heavier walls and a solid roof. The glazed roof and frames come off, brick or stone piers and a new insulated roof with a lantern go on, and the room becomes a year-round part of the house. It is a building project rather than a refurbishment, and the new roof will need building regulations approval.
Why convert a conservatory to an orangery?
Many older conservatories were built with basic glazing and lightweight frames. While they let in plenty of light, they often struggle with insulation. An orangery adds solid walls, better glazing, and a roof lantern, making it a true year-round living space.
This change can transform the room’s appearance, add property value, and make it more functional for daily use. Converting rather than replacing also has practical advantages:
Retains part of the existing structure, reducing cost.
Improves insulation and comfort levels.
Offers a more permanent architectural style.
Increases property value.
What is involved in a conservatory to orangery conversion?
The process depends on your existing structure. In most cases, the frames and roof are removed, while the base and foundations remain in place, provided a survey confirms the existing footings can carry the heavier walls and roof. Brick or stone walls are added, along with high-performance glazing and a new insulated roof with a lantern feature.
Any necessary reinforcements are made to ensure the structure meets current building regulations. Step by step, a typical conversion runs like this:
Survey and design. We measure the conservatory, look at how it meets the house and agree the layout, roof form and doors. This is also when planning and building regulations are checked.
Footing and base check. The foundations are exposed in one or more places to confirm their depth and condition. A conservatory base was designed for a light glazed structure, so it may need underpinning or new footings under the piers.
Structural design. An engineer calculates the new roof, the lantern opening and any beams over wide openings into the house.
Strip-out. The old roof, frames and glazing are removed, usually leaving the base and, if they are sound, the dwarf walls.
Walls and piers. Brick or stone piers and any new wall sections are built to match the house, with cavity insulation where the design allows.
Roof and lantern. The insulated flat roof deck goes on, with the lantern set into it, the fascia around the edge and the covering on top. At this point the room is weathertight.
Glazing and doors. New hardwood or aluminium windows and doors fit between the piers.
Finishes. Plastering, the pelmet and ceiling, electrics, heating, flooring and decoration.
What can be kept from the existing conservatory?
Usually the concrete base and slab, if it is level, dry and has a damp-proof membrane, and often the dwarf walls, if they are plumb, in good condition and deep enough footings sit beneath them. The survey decides this, not the age of the conservatory. The frames, glazing and roof are nearly always replaced, because the new roof is heavier and the old frames were never designed to carry it. Floor insulation is worth checking at the same time, since many older bases have little or none.
Roof options for the conversion
The roof is what turns a conservatory into an orangery, so it is the main design decision:
Flat roof with a lantern: the classic orangery, with a warm plastered perimeter and a glazed lantern over the centre.
Flat roof with rooflights: a lower, more contemporary line, with light placed over a table or kitchen island.
Shallow pitched roof with a lantern insert: tiled or slated to match a pitched house.
Our guide to orangery roof types compares these in more depth.
Planning permission considerations
You may not need full planning permission if the footprint and height remain the same. However, if you change the size, shape, or height significantly, you may need to apply. A listed home needs listed building consent, and in a conservation area or National Landscape (formerly AONB) your permitted development rights are more limited. It is best to confirm requirements with your local authority before starting work. Our guide to planning permission for an orangery sets out the limits.
Building regulations
A conservatory is only exempt from building regulations in England while it stays a conservatory: at ground level, no more than 30m², substantially glazed, separated from the house by external-quality doors, with independent heating. Replace the glazed roof with a solid one and it usually stops qualifying, so the converted room is treated as an extension under the regulations. That means approval for the structure, thermal performance of the roof and walls, drainage and safety glazing, with structural calculations for the roof and any new openings. Our guides to orangery building regulations and when a conservatory becomes an extension explain the detail.
Design options for your new orangery
Add bifold or sliding doors for easy garden access.
Choose a hardwood frame for a timeless look or aluminium for a modern feel.
Incorporate underfloor heating for consistent warmth.
Use interior finishes that match the rest of the home for a consistent feel.
A well-designed traditional hardwood orangery can give the space elegance, durability, and better energy efficiency.
How long does a conversion take?
The stages run in the order above: survey and design, approvals, then work on site. Design and approvals typically take longer than the build itself, particularly if planning or listed building consent is needed. On site, the room is out of use from strip-out until the roof and glazing are in, and the finishing trades follow. The biggest variable is the base: if the footings need work, that adds a stage before anything goes up.
Cost of conversion
Converting a conservatory to an orangery is generally more cost-effective than building a new orangery from scratch, as existing foundations and base walls can be reused. However, costs vary depending on materials, glazing, and interior finishes.
How much you save depends on how much of the existing base can be reused once it has been surveyed. The main cost drivers are:
Whether the footings need strengthening or replacing.
The size of the room and the roof form, including a single or double lantern.
The frame material and glazing specification.
The width of any new openings into the house and the steelwork they need.
Heating, lighting and the level of interior finish.
Our orangery cost guide explains what drives the price of a new orangery, which is the useful comparison.
Conversion or solid roof replacement?
A solid roof replacement keeps the conservatory frames and swaps only the glazed roof for an insulated one. It is quicker and simpler, but the walls stay mostly glass and the room keeps the look of a conservatory. A full orangery conversion rebuilds the walls with piers, replaces the frames and adds a lantern, so it costs more but gives a warmer, more permanent room with a proper orangery roof and fascia. If the frames are old or failing, conversion usually makes more sense.
Conservatory to orangery questions, answered
Can I keep my conservatory's dwarf walls?
Sometimes. If the survey shows the walls and the footings beneath them are sound and deep enough for the new loads, they can be reused and clad or rendered to match.
Is a converted orangery warmer than a conservatory?
Yes. The insulated roof, solid piers and modern glazing lose far less heat than a glazed conservatory roof, which makes the room usable all year.
Talk to our design team
If you would like to know whether your conservatory can be converted, talk to our design team about a survey.
