What are the benefits of adding solar PV during a re-roofing project?

A full re-roof is usually considered because the existing covering is deteriorating, weather performance has declined or wider improvements are needed. Once scaffolding, labour and materials are being organised, the project also creates an ideal opportunity to consider whether the roof could do more than simply protect the property.

Installing solar PV alongside the roofing work can turn a necessary refurbishment into a wider energy upgrade. By planning both elements together, homeowners, housing providers and architects can reduce duplication, limit disruption and ensure the array is properly integrated into the finished roof.

Why install solar PV during a re-roofing project?

Solar PV can be added on top of an existing roof covering, but there is little value in installing panels over a covering that may soon need replacing. If major roofing work is already planned, it makes sense to assess the new covering and solar system together.

Having scaffolding and access equipment already in place can reduce duplicated costs and avoid the need to return for a second project. It also gives the project team more control over the array layout, cable routes and inverter position before work begins.

Roof windows, chimneys, hips and valleys can affect where panels are installed. Considering these features at the design stage makes it easier to use the available space effectively and avoid compromises later.

Reducing reliance on grid electricity with solar PV during a re-roofing project

Solar PV generates electricity that can be used within the property for lighting, appliances and other electrical demand. Every unit used on site reduces the amount that needs to be purchased from the grid.

The savings available will vary between properties. System size, roof orientation, pitch and shading all influence generation, while the occupants’ energy-use patterns affect how much of that electricity can be used within the building.

A PV system which forms part of a full re-roofing project, should therefore be designed to suit the property rather than based on the assumption that the largest possible array will always provide the best outcome. Available roof area needs to be considered alongside likely electricity demand and the times at which the building uses the most power. For housing providers, applying this approach across suitable homes can help reduce residents’ reliance on grid electricity costs, and can improve existing housing stock through a longer-term assurance of the roof longevity which should be supplied with a warranty. This will need checking with the roof system supplier.

Lowering operational carbon with solar PV

Operational carbon is associated with the energy used while a building is occupied. Generating renewable electricity on the roof reduces the amount drawn from the grid and can therefore lower the emissions linked to day-to-day operation.

Solar PV should form part of a wider approach to improving the property. Roof insulation and other building-fabric measures can reduce energy demand, while solar PV helps meet part of the remaining electrical load.

A planned roof refurbishment may allow several improvements to be coordinated within one programme. For housing providers managing larger estates, repeating this approach across suitable properties can support wider carbon-reduction goals.

Making better use of existing pitched roof spaces

A pitched roof performs an essential weatherproofing function, but most of its surface otherwise remains passive. Solar PV allows part of that space to generate usable electricity without requiring additional land or a separate structure.

Not every section of roof will be equally suitable for the installation of Solar PV. Roofs with significant undulations in the rafters can make the fitting of Solar PV very difficult, shading from trees or neighbouring buildings can reduce output, while complex roof shapes may limit panel positioning. However, many of these issues can be addressed when solar is considered during the planning stage of a re-roofing project.

Integrated PV systems can also replace part of the conventional roof covering rather than being mounted above it. Marley SolarTile® sits within the roof, creating a more unified appearance while reducing the number of standard tiles or slates required.

For homeowners and architects, this can provide a cleaner visual aesthetic. For housing providers, coordinating the roof covering and solar system may also support greater consistency across repeat projects.

Preparing for future energy needs

The way homes use electricity is changing. Heat pumps and electric vehicle charging can increase demand, while battery storage allows households to retain more of the electricity generated by solar PV.

A battery can store surplus solar power produced during the day for use later, including during the evening when household demand is often higher. This can increase the amount of renewable electricity used within the property rather than exported to the grid.

Not all of these technologies need to be installed at once. However, considering them during a re-roofing project can make later upgrades easier by ensuring the array, inverter and wider electrical system suit the property’s likely future requirements.

Futureproofing is not about adding every available technology immediately. It is about avoiding decisions during the refurbishment that could make the next stage more difficult or expensive.

What should be considered before installing solar PV during a re-roofing project?

A successful solar roof retrofit begins with a proper assessment of the building. The condition of the roof structure, available area, orientation, pitch and likely shading all need to be reviewed before the array is designed.

The proposed system should also reflect how the property is used. Current electricity demand, future heating plans and the possible addition of battery storage or EV charging can all influence the most appropriate array and inverter specification.

For occupied housing, careful coordination is needed to minimise disruption and maintain weather protection throughout the work. Social housing providers may also need to consider resident communication, access arrangements and how a repeatable specification can be applied across different property types.

Adding Marley SolarTile® during as part of a re-roofing project

Marley SolarTile® is an integrated solar PV system for pitched roofs. The panels replace an area of standard tiles or slates, combining weather protection with on-site electricity generation.

With the system being installed as part of the roof covering, re-roofing works present an ideal opportunity to consider the size and position of the array alongside the other roofing components. This helps create a coordinated specification and avoids unnecessary work later.

Adding solar PV during a full re-roof can reduce grid electricity use, lower operational carbon and make better use of an existing building surface. It can also provide a foundation for battery storage, electric heating and vehicle charging as the property’s energy requirements develop.

Planning to re-roof your building? Contact our expert team or use the Marley solar configurator to begin planning your array.


Disclaimer - The information shared in this blog is correct at the time of publication. Guidance, standards, and best practices may change over time, so if you’d like further clarification or the latest updates, please get in touch with the Marley Technical Advisory Team, who will be happy to help.