How to Choose a Solar Canopy Installer: 15 Questions to Ask

A solar canopy is not a big roof system. It is a steel structure that happens to carry panels, built in a car park or a play area, wired to a grid connection that may need the network operator’s permission. The frame alone is roughly 45% of what you pay, according to the costings on our cost page, so the firm you choose is mostly choosing a structural engineer, a steel fabricator, a groundworker and an electrician at once. This guide gives you fifteen questions you can put to any canopy contractor, grouped by what can go wrong, plus the red flags and a like-for-like table for comparing quotes.

One thing to be clear about first. This site is an independent guide, not an installer. We do not carry out installations, we cannot vouch for any named firm, and nothing here replaces checking the public registers and asking for documents. Every question below is built so that the answer is something you can ask to see.

Why choosing a canopy contractor is different from choosing a roof installer

On a roof, the building already exists. On a canopy, the contractor designs and builds the thing the panels sit on. That brings in four risks that rarely arise on a rooftop job: structural failure under wind and snow, groundworks that hit buried services, planning conditions, and a bigger electrical connection. The questions below follow those risks in turn. If a contractor cannot answer the structural questions in writing, it does not matter how good their panel warranty looks.

Structure and engineering (questions 1 to 4)

1. Who designs the structure, and to which loads?

Ask for the name and professional status of the engineer who designs the frame, and for the design basis. For UK canopies this normally means wind and snow actions taken from BS EN 1991-1-4 and BS EN 1991-1-3 with their UK National Annexes. A canopy is a large, lightly clad surface, so wind uplift is the critical case. “Our standard design” is not an answer; the loads depend on your site’s location, altitude and exposure.

2. How is the steelwork made, and how is it protected?

Structural steelwork placed on the UK market is expected to be CE or UKCA marked under BS EN 1090-1, which means the fabricator operates factory production control. Ask for the fabricator’s certificate and the execution class they are working to. Ask how the steel is protected: hot-dip galvanising to BS EN ISO 1461 is the usual route for car-park canopies, and our steel versus timber comparison explains why. A canopy that rusts at the base in year five is a maintenance bill for you, not for the contractor.

3. What do they know about the ground?

Columns need foundations, and foundations need to know what is underneath. Ask whether the price includes a ground investigation and a buried-services survey, what foundation type they are assuming (piled, pad or ballasted) and what happens to the price if the ground turns out to be different. Car parks are full of drainage, ducts and cables that nobody drew accurately. A fixed price that excludes ground risk is not a fixed price.

4. What happens to drainage and lighting?

A canopy changes where rain lands and can shade existing lamp columns. Ask how roof drainage will be collected and discharged, whether the existing car-park lighting design has been checked, and whether the layout keeps the headroom and turning space your delivery vehicles need.

Planning and consents (questions 5 to 7)

5. Which planning route are you assuming, and who submits it?

In England a solar canopy over a non-domestic car park can fall under permitted development Class OA subject to prior approval, which our planning permission guide explains in detail. Wales and Scotland follow different rules, and a site in a conservation area, near a listed building or with existing planning conditions may need a full application. Ask the contractor which route they expect, who prepares and submits it, whether the fee and the supporting drawings are in the price, and what the timetable is.

6. Have you checked the site’s constraints?

Ask whether they have looked at conservation-area and listed-building status, tree preservation orders, flood-risk zones and any conditions on the original car-park consent. A good contractor raises these before you do.

7. Do Building Regulations apply, and who signs it off?

Structures and electrical work can attract Building Regulations. Ask the contractor to state in writing whether building control is involved, who deals with it, and what certificates you will receive at handover.

Electrical and grid connection (questions 8 to 10)

8. G98 or G99, and who applies?

Up to 16 A per phase, which is about 3.68 kW single-phase or roughly 11 kW three-phase, a generator is connected under G98 and notified within 28 days. Above that, G99 applies: you apply to the distribution network operator and must have approval before you connect. Most commercial canopies sit above the G98 limit. Ask who makes the application, what studies the network operator is likely to require, how long the quoted programme assumes for the response, and who pays if the network operator asks for a network reinforcement or imposes an export limit.

9. What is the export and metering plan?

Many car-park canopies self-consume most of what they generate during the working day, but weekends and holidays produce surplus. Ask whether the design includes export limitation, how the generation will be metered, and whether the price assumes you register for an export tariff under the Smart Export Guarantee. Ask for the self-consumption assumption behind any payback figure and for the half-hourly data it was based on.

10. Which inverters, and are they accepted by the network operator?

Inverters connected to the UK network have to appear on the Energy Networks Association type-test register. Ask for the make and model, the register entry and the warranty terms, and who is responsible for monitoring and for replacing an inverter in year ten or twelve.

Safety, contract and aftercare (questions 11 to 15)

11. Who are the principal designer and principal contractor under CDM 2015?

Under the Construction (Design and Management) Regulations 2015, a project involving more than one contractor needs a principal designer and a principal contractor, and the client has statutory duties of its own. Larger or longer projects also have to be notified to the Health and Safety Executive. Ask the contractor to name who will hold each role, to show you a draft construction phase plan, and to explain how pedestrians and vehicles will be separated from the works while the car park stays open.

12. What insurance do they hold, and can I see the certificates?

Employers’ liability insurance is a legal requirement for firms that employ staff, with a minimum cover of £5 million. Public liability and contract works cover are not compulsory by law but should be in place for a project of this kind. Ask for the certificates and check the limits against the value of your site and the neighbouring property.

13. Who does the electrical work and how is their competence shown?

Ask which firm will carry out and certify the electrical installation, and how its competence is assessed. Competent-person scheme membership such as NICEIC or NAPIT is common for electrical contractors, and you can check an entry on the scheme’s own register. For installations up to 50 kW, MCS certification may also matter, particularly if you intend to claim export payments; check the MCS public register directly. Do not rely on a logo on a website or a brochure.

14. What warranties, monitoring and maintenance are included?

Separate the warranties: panels, inverters, structure and workmanship all have different periods and different claimants. Ask what monitoring is included, what the operations and maintenance price is after year one, who cleans the panels if they are mounted where you cannot reach them, and what happens to the warranty if the contractor stops trading. A parent-company guarantee or an insurance-backed warranty is worth more than a promise.

15. Can I speak to someone who has had a project like mine?

Ask for references from projects of a similar size and structure type, ideally ones you can visit or telephone. Treat anonymous “case studies” and rounded satisfaction figures with caution; a contractor who can introduce you to a named client with a canopy that is two or three years old has something to show.

Red flags

• A solar-only payback of five years or less on a canopy. The structure is a large share of the cost, so a payback that short on the PV alone is not realistic. See the worked numbers on our carport cost guide.
• A “free” canopy with no terms. If someone else funds it, you are in a power purchase agreement or a lease. Read our buy versus PPA comparison before you sign anything.
• No structural calculations on request. A contractor who cannot show the design basis has not done one you can rely on.
• No grid plan. If G99 is described as “a formality”, the programme and the price are probably wrong.
• Pressure to sign this week because of an unnamed deadline or a discount that disappears.
• Accreditation claims you cannot verify on the public register or the issuing body’s own website.

How to compare three quotes like for like

Compare	Ask each contractor to state
Scope	kWp, number of panels, bays covered, frame type and material, finish
Structure	Design basis, engineer named, steelwork certification, foundation assumption
Consents	Planning route, who applies, fees included or excluded
Grid	G98 or G99, who applies, programme allowed, export limit risk
Safety	CDM roles named, insurance limits, construction phase plan
Price	Fixed or provisional, what is excluded (ground, network works, traffic management), payment stages
Output	Annual kWh, yield assumption, self-consumption assumption, degradation
Aftercare	Warranty by component, monitoring, O&M price, response time

The cheapest quote is often the one with the most exclusions. Put the exclusions in a row of their own and price them before you decide.

Where to start

Before you speak to anyone, collect your half-hourly electricity data, a site plan, the car park’s existing consent and a note of what you want the canopy to do. Read the cost guide so that you can tell a realistic price from an unrealistic one, check the funding position for your sector, and use the locations index to see our local planning notes for your area. Then request a quote: we reply by email, and any survey or quote that follows is arranged with an installer you choose.

Frequently asked questions

Is MCS certification needed for a solar canopy?

MCS certification applies to small-scale installations up to 50 kW. Many commercial canopies are larger, so an installer's MCS status tells you little about a larger canopy. For anything under 50 kW that you want to claim Smart Export Guarantee payments on, check the installer's entry on the MCS public register yourself.

What is the difference between G98 and G99 for a canopy?

Up to 16 A per phase (about 3.68 kW single-phase or roughly 11 kW three-phase) a system is notified under G98 within 28 days of connecting. Above that you need DNO approval under G99 before you connect. Most commercial canopies need G99, so ask the installer who applies, when, and what happens if the network operator asks for export limitation.

Who is responsible for safety on a canopy build?

Under the Construction (Design and Management) Regulations 2015, a project with more than one contractor needs a principal designer and a principal contractor, and the client has duties too. Ask who holds each role on your project and for the construction phase plan before work starts.

Should I get three quotes?

Yes, but only if they are like-for-like. Give each installer the same site drawing, the same half-hourly electricity data and the same brief, and ask for the quote in the same format, using the comparison table in this guide.