The questions that separate a good conservatory roof installer from a risky one are about paperwork, not sales talk. Ask for the panel thickness and U-value in writing, who applies to building control, whether the 10 year guarantee is insurance backed, and how much deposit they want. A fair deposit is rarely more than about 25% of the price.
How to use this list
Take these questions to every survey or phone call, and write the answers down. If you are comparing two or three quotes, the written answers side by side will tell you more than the headline price. A quote that looks £500 cheaper can easily be missing building control, removal of the old roof or a proper guarantee.
We have added what a good answer sounds like after each one. These are the answers we would expect to give ourselves.
About the roof itself
1. What thickness is the insulation core, and what is the U-value?
This is the most important technical question. A good installer gives both numbers and can explain how the U-value was reached. As a guide, a 25 mm foam core gives about 1.14 W/m²K, 50 mm about 0.62 and 75 mm about 0.43. Our guide to conservatory roof panel thickness shows the sum.
Good answer: a thickness in millimetres, a U-value, and both written on the quote.
2. Are the panels made to measure for my roof?
Panels cut to fit on site from stock sizes can leave gaps and joints that leak air. Made to measure panels are produced to the survey dimensions of each bay.
Good answer: yes, from measurements taken at the survey, with a lead time of a few weeks.
3. Will you check my frame and base before quoting?
Any new roof relies on the frame and base underneath it. An installer who quotes from photos alone, without looking at the roof bars, ring beam and dwarf wall, is guessing. Our guide on whether your frame can take a solid roof lists what should be checked.
Good answer: a survey in person, with anything that needs fixing written on the quote.
4. What happens to the old roof?
Taking off the old polycarbonate or glass and getting rid of it takes time and costs money. Some quotes leave it out.
Good answer: removal and recycling are included in the price.
About the paperwork
5. Who applies to building control, and is the fee included?
Fitting a solid insulated roof removes the building regulations exemption for conservatories, because at least 75% of the roof must be translucent for the exemption to apply. Approval is normally needed. An installer who says it is not needed at all is either wrong or skipping it, and you will find out when you sell.
Good answer: they agree the spec with building control before ordering, apply on your behalf, and include it in the price.
6. Will I get a completion certificate?
The completion certificate is the proof the work was signed off. Your buyer's solicitor will ask for it. Our guide to selling a house with a replaced conservatory roof explains why it matters.
Good answer: yes, after building control sign off, with the guarantee paperwork.
7. Do I need planning permission?
Planning permission is not normally needed because the footprint and height do not change. Listed buildings, conservation areas, national parks, National Landscapes and homes where permitted development rights have been removed are the exceptions.
Good answer: usually not, but they ask whether any of those apply to you.
About the guarantee
8. Is the guarantee insurance backed?
A guarantee from the installer alone is only as good as the business. An insurance backed guarantee is designed to protect you if the installer stops trading.
Good answer: yes, with the length stated and the document provided at the end. Ours is 10 years.
9. What exactly does the guarantee cover?
Ask whether it covers the panels, the fitting, leaks and the seals, and what you need to do to keep it valid. Ask whether it passes to a new owner if you sell.
Good answer: a written list, not a verbal promise. See our guarantees page for what ours includes.
About money and timing
10. Is the quote fixed, and what could change it?
A fixed written quote after a survey should not move unless you add something or a hidden problem is found once the old roof is off. Ask what would count as a hidden problem and how it would be priced.
Good answer: a fixed price with the extras listed separately, such as roof lights, LED spotlights or new gutters.
11. How much deposit do you want, and when is the balance due?
A large deposit is a risk if anything goes wrong before fitting. As a rule, a deposit much above 25% of the price is worth questioning, and full payment up front is a warning sign.
Good answer: a modest deposit with the balance due when the work is complete.
12. How long will it take, and do I need to be at home?
Fitting times vary with size. For panel roofs a small lean-to or Edwardian usually takes one day, a medium roof one to two days and a large or P-shaped roof two to three days. Most single storey roofs need no scaffold.
Good answer: a clear number of days, a lead time from survey, and a plan for rain.
Comparing quotes side by side
Copy this table onto paper for each quote. Gaps in the right hand column are where the price differences usually hide.
| Item | What to write down |
|---|---|
| Core thickness and U-value | Both numbers, in writing |
| Made to measure | Yes or no |
| Old roof removed and recycled | Included or extra |
| Building control application and fee | Included or extra |
| Completion certificate | Yes or no |
| Guarantee length and insurance backing | Years, and backed or not |
| Extras | Roof lights, lighting, gutters and fascia, each priced |
| Deposit | Amount and when the balance is due |
| Fitting time and lead time | Days on site, weeks from survey |
If you sign a contract in your own home, you normally have 14 days to cancel under consumer law. Any installer who pushes you to sign on the day for a one-off discount is using pressure, not giving you a better price.
Red flags to walk away from
- A price that is only valid if you sign today.
- No written U-value, or a very low U-value for a thin panel.
- "You don't need building regs for this."
- No survey of the frame before quoting.
- Full payment before the work starts.
- A guarantee that is not insurance backed, or no written terms.
How our prices compare
For reference, our fitted prices include removal of the old roof, 75 mm panels made to measure in your colour, fitting, the building control application and a 10 year insurance backed guarantee. Small roofs up to 12 m² start from £3,000, medium roofs from £4,000 and large or P-shaped roofs from £5,000. Most homes pay £3,000 to £7,500. Extras are priced separately: glazed roof lights £395 each, LED spotlights £345, and new gutters and fascia £295.
Next steps
Use the conservatory roof cost calculator to get a price range before anyone visits. Then book a free survey and put all 12 questions to us. You can read the full process on how it works.
Questions people ask
How many quotes should I get for a conservatory roof?
Two or three is usually enough to see a fair price. Compare them line by line on thickness, U-value, building control, removal of the old roof and the guarantee, not just the total.
What deposit is normal for a conservatory roof?
A modest deposit, rarely much more than about 25% of the price, with the balance due on completion. Full payment up front is a warning sign.
Should the installer handle building control?
Yes. A solid insulated roof normally needs approval, and a good installer agrees the specification with building control, applies for you and hands over the completion certificate.
What does insurance backed mean on a guarantee?
It means an insurer stands behind the guarantee, so it is designed to protect you if the installer stops trading. Ask to see the terms in writing.
