What the job involves
Replacing a conservatory roof means taking off the existing roof, usually tired polycarbonate or older glass, and fitting a new one on the existing frame and base. Most homeowners choose one of three routes:
- A new glazed roof. Modern glass units, often with a solar control or self-cleaning coating, replace old polycarbonate sheets. You keep the light but the room is much less prone to overheating and noise.
- A solid, lightweight tiled roof. A purpose-made system with insulation, a tiled or slate-effect finish and a plastered ceiling inside. The room feels more like part of the house and is easier to heat.
- A hybrid roof. Mostly solid, with a roof lantern or a few roof windows to let light in.
The work normally includes erecting scaffolding or access equipment, stripping and disposing of the old roof, checking and sometimes strengthening the frame, fitting the new roof, sealing it to the house wall, and sorting guttering and finishing. A solid roof adds insulation, internal plastering and often lighting.
The frame matters more than most people expect. A solid roof is much heavier than polycarbonate, so the walls, frame and foundations must be able to carry it. A sensible installer will inspect these before quoting firmly.
What affects the price
Two conservatories that look similar from the garden can be priced very differently. The main drivers are:
- Size and shape. A larger roof needs more materials, more labour and more time on scaffolding. Complex shapes with multiple facets, such as Victorian or P-shaped designs, take longer to measure, make and fit than a simple lean-to.
- Type of roof. Glass is generally priced differently from a full solid system, and a hybrid with a lantern sits somewhere in between depending on the specification. Premium glass coatings cost more than a basic unit.
- Tile or slate choice. Lightweight tile systems vary in finish and quality. Products that closely imitate natural slate or clay usually cost more than plainer options.
- Condition of the existing frame. Rotten timber, tired uPVC or weak corners may need repair or reinforcement before a new roof can go on. This is the most common source of extra cost.
- Structural work. Some solid roofs call for steel reinforcement, a new wall plate or alterations to the base. Your installer or a structural engineer should advise.
- Access. Tight side access, steep gardens or a conservatory attached to a two-storey wall can mean more scaffolding, more labour and more care.
- Internal finishing. Plastering, decorating, spotlights, new sockets and making good around the walls all add to the job. A plain glazed roof avoids most of this.
- Roof windows and lanterns. Each one adds materials, opening mechanisms and extra weatherproofing.
- Guttering, fascias and flashings. Replacing these at the same time is sensible, but it adds to the total. The junction with the house wall needs careful sealing, often with lead flashing.
- Building regulations. Fitting a solid roof usually means the conservatory no longer qualifies for the exemption that glazed ones often enjoy, so building regs approval is normally needed. Fees and paperwork add to the cost.
- Your location and the time of year. Labour rates differ across the UK, and good installers are busiest in warmer months.
Ways to keep the cost down
- Get several quotes for the same specification. Decide whether you want glass, solid or hybrid first, so each quote is comparable.
- Keep the design simple. Fewer roof windows and a straightforward finish usually mean less labour.
- Have the frame inspected early. Finding a problem before work starts is cheaper than discovering it with the roof off.
- Do your own decorating. Leave the plastering to the professionals, but painting afterwards is something many people do themselves.
- Choose the right roof for how you use the room. If it is a utility room or occasional space, a full solid roof with a high-end finish may be more than you need.
- Be flexible on timing. Some firms have quieter periods and may be more open to negotiating.
- Avoid changing your mind mid-job. Variations, such as extra electrics or a different tile, cost more once work is under way.
What should be included in a quote
A proper quote should be written, itemised and specific. Check that it covers:
- [ ] The full roof specification: glass type and coating, or tile system and insulation details
- [ ] Scaffolding or access equipment
- [ ] Removal and disposal of the old roof
- [ ] Inspection of the frame and what happens if repairs are needed
- [ ] Any structural strengthening, with who has designed it
- [ ] Roof windows, lanterns, vents and trims
- [ ] Guttering, fascias and flashings
- [ ] Internal work: insulation, plastering, decorating, lighting and electrics
- [ ] Building regulations application and sign-off, and who pays for it
- [ ] Whether VAT is included
- [ ] Payment schedule, with the final payment tied to completion
- [ ] Start date, expected duration and what happens if weather delays work
- [ ] Guarantee details for both the product and the workmanship, in writing
- [ ] Insurance cover held by the installer
Questions to ask a window fitter
- Have you inspected the existing frame and base, and are they suitable for this roof?
- Will you arrange building regulations approval, and do you deal with the building control body?
- Who does the structural calculations if reinforcement is needed?
- Is the electrical work carried out by someone qualified, and who certifies it?
- What happens if you find rot or damage once the old roof is off?
- Is the roof made to measure, and when will it be ordered?
- Who will be on site: your own employees or subcontractors?
- How do you protect the inside of the room and the rest of the house during the work?
- Can I see a similar job you have completed, or speak to a recent customer?
- What does the guarantee cover, and who do I contact if there is a problem?
How long it takes and what to expect
A glazed replacement is usually the quicker job. A solid roof takes longer because of the extra layers, the internal plastering and the drying time. Larger or more complex conservatories take longer still. Weather matters, because the roof is open at some stage and a good installer will plan around the forecast.
Expect scaffolding to go up first, followed by stripping the old roof. The frame is then checked and prepared, and the new roof is installed and sealed. Internal finishing comes last on a solid roof. Expect noise, dust and some disruption to the garden and the rooms next to the conservatory. Clear the room of furniture beforehand and protect floors.
Before making the final payment, check the finish, look for any leaks after rain, make sure windows open properly, and ask for all certificates, guarantees and building regulations paperwork.
Signs a quote is too cheap or too expensive
Too cheap
- No site visit, or a quote given without looking at the frame
- A vague description such as "new roof" with no specification
- No mention of building regulations for a solid roof
- Pressure to pay a large sum upfront
- No written guarantee or insurance details
- Scaffolding, waste removal or finishing left out
- A price far below the others, which often means corners cut or extras added later
Too expensive
- Costs bundled into one figure with no breakdown
- Premium products specified without you asking for them
- Structural work proposed with no explanation or calculations
- Large allowances for "unforeseen problems" without detail
- A quote that is much higher than others for the same specification, with no clear reason
Compare the prices on this page with your own quote. If yours sits well outside what other homeowners paid for similar work, ask the installer to explain exactly why before you commit.