The quote was right for the roof you thought you surveyed. The crew turned up to the one that was there.
Part of the series Survey and design: getting the roof right before you quote.
Three weeks after the survey, the questions start
The survey was on a Tuesday, between a call-back and a school run. The surveyor looked at the roof from the drive and put "tiles" on the pad, glanced at the fuse box and wrote "looks fine", and noted that the battery could go under the stairs. The quote went out on Thursday.
Three weeks later the roofer asks whether the tiles are clay or concrete. The electrician asks for the MPAN and whether the supply is single-phase, because the DNO paperwork needs both. The scaffolder rings to say the back of the house is a shared alley and the tower will not go where it was priced. The designer says the battery cannot go under the stairs. The quote is re-issued for a higher figure, and the customer starts wondering what else was guessed.
Nobody did anything wrong. The surveyor was rushed off their feet. But the quote was built on a sheet with blanks on it, and every blank became a phone call, a return visit or a re-quote.
The sheet. Four headings, one reason for each line.
Fill it in the house, not in the van afterwards. It can start on paper once. After that it lives on the job record, where the designer, the electrician and the scaffolder read it without ringing you.
The roof
- Covering: slate, clay tile, concrete tile, metal, felt, fibreglass or rubber. The fixings and the roofer's price change with it. "Tiles" is not an answer.
- Type, pitch and orientation of every usable plane. The panel count and the yield estimate rest on these three numbers. A guessed pitch is a guessed quote.
- Condition. A roof that needs work before panels go on is a different job. The customer hears it before the quote.
- Usable area and what is in the way. Windows, vents, aerials and chimneys decide whether it is 13 panels or 14. Measure it.
- Shading, and what causes it. Trees, the neighbour's extension, the chimney. Name the source so the designer can plan round it.
- Bird proofing wanted, yes or no. It is a line on the quote or an argument after the install.
- Listed building or conservation area. Either can mean planning before anything else happens. Write the answer down even when it is no.
The electrics
- Supply phase: single or three. It decides the inverter and the DNO route. Under ENA Engineering Recommendation G98, up to 16 A per phase (3.68 kW) is connected and notified afterwards. Above that is a G99 application before the install, and the wait that comes with it.
- Supply type: underground, overhead or looped. A looped supply is shared with the neighbour and changes what the DNO will allow.
- Main fuse rating and earthing arrangement. The electrician designs the AC side from both. Photograph the cut-out.
- The MPAN, and the export MPAN if there is one. The DNO notification and the export tariff both need it. It is on the bill. Photograph it.
- Meter type, and whether it is a smart meter. The export tariff conversation starts from it, and that conversation belongs before the sale, not after.
- Consumer unit: where it is, what type, how many spare ways. No spare way means a new board or a separate unit, and the quote has to carry it.
The site and access
- Scaffold required, and where it stands. Ground conditions, the neighbour's side, the conservatory. The scaffolder prices from this line, and a scaffold left out of a quote is the one that gets argued over. If it is a cherry picker instead, say so now.
- Parking and unloading. A permit street or a shared drive costs the crew an hour a day.
- Loft access: hatch with ladder, hatch without, boarded, or none. A crew that cannot get into the loft cannot run the cables or fit the inverter there.
- Cable routes and their lengths, DC and AC. Length sets the cable size and the labour. Draw the route.
- Asbestos, and anything else that affects safety on site. Soffits, garage roofs, old water tanks. The crew needs to know before they cut.
The customer and their kit
- Proposed battery location, and its capacity. PAS 63100:2024 rules out lofts and roof voids, bedrooms, cupboards opening onto a bedroom, hallways, stairwells and landings, and bathrooms. A garage, a utility room or an outbuilding is preferred. Outdoors on a wall, a kitchen, a living room, an internal cupboard and a cellar are allowed with conditions, and the standard limits one enclosure to 20 kWh. Settle it in the house, with the customer, and note the conditions still to confirm.
- Inverter location. It fixes the cable runs above and the Wi-Fi question below.
- EV charger location, if one is wanted. The cable route and the fuse capacity both follow from it.
- Wi-Fi where the inverter will be. Monitoring that never connected is the second visit nobody pays for.
- Who lives there and who decides. Owner, landlord or tenant, and whether both partners need to see the quote. A tenant needs the landlord's consent.
- Existing system, consumption and the bill. Panels already on a FIT tariff make it a battery retrofit, and the savings estimate is only as good as the kWh figure it starts from.
- What the customer was told. "The battery will go in the garage" is a promise. Write it where the designer can see it.
The sheet fails when it is filled in from memory
A sheet completed in the van from a few photographs has the same blanks as no sheet at all, because the questions were never asked while the answer was in front of you. Two things stop that. Treat a blank line as a reason not to send the quote yet. And keep the sheet on the job, not on a phone, so the scaffolder's price and the string design come from the same answers.
Installa does the survey sheet for you
- Stop carrying the sheet. The survey form is the sheet. It asks every question above, from the roof covering and the supply phase to the MPAN, the spare ways, loft access, cable lengths, scaffold and parking, and the proposed battery, inverter and EV charger locations.
- Stop checking the battery location against the standard afterwards. Choose the proposed location on the form and it tells you there and then whether PAS 63100:2024 rules it out, allows it with conditions it spells out, or prefers it, and it flags a battery over 20 kWh in one enclosure.
- Stop asking the office what was said at enquiry. Who is buying, the existing system, annual consumption, the bill, timeframe and decision-makers are captured on the enquiry, so the surveyor arrives knowing them.
- Stop losing the survey date. Surveys sit on the team calendar with the surveyor's name on them, so the office can see who is where.
- Stop measuring the roof from the pavement. The 3D designer builds the roof from satellite imagery and a 3D height model of the building, and places the sun from the site's own latitude and longitude for any day and hour.
- Stop hunting for the photographs. Documents attach to the survey record, next to the answers they back up.
Every line filled in the house, on the job record, before the quote goes out. That is the whole routine, and it is what the survey form is for. See how 3D solar design in Installa works, or try the sun path simulator on a roof you know.