Cornerstone Group
0800 011 9758Start a project
Home / Case studies / Booker Watford

Booker Watford Roof & Solar

A new roof and a 334 kWp solar PV system delivered together for Booker’s Watford cash-and-carry: one coordinated programme, a 20-year warranty and a 3.1-year payback.

Start a similar project
Booker Watford from the air, with solar arrays across the new roof above the branded entrance

The opportunity

Booker wanted to cut operating costs and improve energy efficiency while securing long-term structural reliability. The existing roof was due for replacement: the ideal moment to integrate solar. We delivered it through a partnership between Cornerstone (solar) and NWIR (roofing), so the new roof and array went on as one job.

The solution

A high-quality, weather-resistant roof engineered to carry the panels, topped with a 334 kWp array using smart inverters. Export was capped at 200 kW to meet DNO requirements, with on-site consumption prioritised to maximise savings. Both roof and system carry a 20-year warranty.

The outcome

A 3.1-year payback, materially lower energy bills, additional revenue from exported power and low ongoing maintenance, cutting roughly 70 tonnes of CO₂ a year and supporting Booker’s sustainability goals.

Project facts
ClientBooker Wholesale, Watford
System size334 kWp solar PV
RoofNew roof with integrated PV
Warranty20 years: roof & solar
Payback3.1 years
334 kWpRooftop array
3.1 yrsPayback period
~70tCO₂ saved a year
20 yrWarranty

“The combined expertise of Cornerstone and NWIR delivered a seamless roof and solar solution, with immediate savings and long-term reliability.”

Booker Watford · Facilities Manager
More case studies

Explore more of our work.

Energy · 114 kWBooker Newton Abbott
Energy · 750 kWFDC Solar PV Scheme
Energy · 75 kWBilsborrow Hall Farm
All case studies
Project gallery

Booker Watford in pictures.

Photographs from site, from early works through to handover. Select any image to enlarge it.

Two large solar arrays running along the re-roofed Booker Watford warehouse
EnergyBooker Watford
Front aerial of Booker Watford with solar on both roof pitches
EnergyBooker Watford
Close aerial of the solar array across the Booker Watford roof sheets
EnergyBooker Watford
Booker Watford site from above showing the roof, array, car park and loading yard
EnergyBooker Watford
Booker Watford warehouse elevation with the new roof and solar seen from the car park side
EnergyBooker Watford
Rear aerial of the Booker Watford building and its rooftop solar array
EnergyBooker Watford
All projects
Further reading

Guides and project stories.

All insights
Project spotlightProject spotlight: Booker Watford roof and solarHow a roof that was due for replacement became the platform for a 334 kWp solar array at Booker Watford, with a 3.1-year payback.Read the article GuidesShould you re-roof before installing solar? The case for doing both togetherWhy roof condition matters before solar, how a combined roof and solar project works, and the warranty when we fit the roof and the solar.Read the article GuidesCommercial solar payback explained: what affects it and how long it takesHow commercial solar payback works, what drives it, from daytime demand to roof condition, and how we model yours before you commit.Read the article

Power your business with solar.

Our renewables team designs, installs and maintains commercial solar, storage and EV charging across the North West and the UK.

Commercial solar PV installationRoof and ground-mounted solar sized to how your building uses power, with a clear payback.Roof and solar with a 30-year warrantyWhen we fit the roof and install the solar, both are covered by one combined 30-year warranty.Battery storage for businessStore cheap or solar power and use it at peak times to cut bills further.

Let's talk about your next project.

One call reaches the whole group. Tell us what you need and we'll bring the right teams together.

Tell us about your project0800 011 9758

Accreditations