The short answer
A garage roof can carry solar panels if its structure is sound, its covering has plenty of life left and the fixings can be made watertight. Panels add weight and wind load, so timbers and walls need checking. Asbestos cement sheets are not a suitable base, and an old covering should be renewed before panels go on so the roof is not stripped again within a few years.
What a roof has to offer a solar array
Solar panels are heavy compared with their footprint, and they behave like sails in a gale. Whatever carries them must bear the array weight all year and resist the uplift wind creates around it. On a garage, the structure is often lighter than on a house, with thinner timbers, wider spans and walls that were never designed for extra load.
That does not rule solar out. It means the roof needs to be assessed as a structure first, and as a place to put panels second. A roofer can look at the timbers, the timber lying along the top of each wall, and the way the roof is tied down, and flag when an engineer should take a view. Where doubt remains, a structural opinion is cheap against the cost of a failed array.
The outside of the roof matters too. Panels need a surface they can be fixed to without compromising its weatherproofing, and the fixings must reach something solid, usually a rafter or purlin, not just the covering. A tired or brittle covering cannot hold them.
Pitch, aspect and shade
The shape of the roof affects how well panels will work, though that is a question for the solar installer rather than the roofer. A pitched garage roof facing roughly towards the sun suits panels better than one facing away or sitting in the shade of a tall house or tree. A low-pitched or flat roof can take panels on tilted frames, but those frames add weight and wind exposure.
Garages often have simple, single-pitch or low gable roofs, which are easy to work on. The verge, which is the edge of the roof at a gable, needs to be sound so panels can sit clear of them. Ventilation and gutters should not be blocked either.
A garage may sit away from the house, in which case the cable run back to the inverter and the consumer unit also needs planning. That is the electrician's concern, but it affects where the panels are best placed.
Covering and age: do the roof first
The most useful rule is that the roof should last longer than the panels. Panels are meant to produce for many years, and taking them off to repair or replace the roof beneath is expensive, because the array has to be disconnected, removed and refitted by two trades.
So a worn covering should be dealt with before the panels go on. If the sheets are tired, the felt is blistering or the tiles are slipping, replace the roof first, and have the mounting points planned into the work. That is the stage at which a roofer can build in extra support or install flashed brackets under the new covering instead of cutting through it afterwards.
Typical lifespans give a sense of the timing. MyBuilder's 2026 guide puts metal roofs at 40 to 70 years, while built-up felt on a flat roof is typically 10 to 20 years, more with a good multi-layer build. A felt garage roof on its last legs is an obvious candidate for renewal before any solar.
Why asbestos sheets are not a base
Many older garages are roofed with corrugated asbestos cement sheets. Drilling or fixing through them releases fibres, and the sheets are brittle and cannot be relied on to carry brackets. Fitting solar over asbestos sheets is not advisable, and any panel installer who follows good practice will refuse to work on them.
The usual answer is to remove the sheets and replace them with a covering that can hold an array, then fit the panels. Under HSE guidance, lifting sheets out whole is non-licensed work. We explain the process on our page about asbestos sheet disposal, and the background to the material itself is in the guide to the asbestos garage roof.
It adds to the project cost, but it avoids covering a hazardous roof with expensive equipment that would then have to be taken off for the very same job later.
Consent and permissions
This page does not restate the planning rules for solar, because they depend on where the building is and what it is. Outbuildings, listed properties, conservation areas and sites with Article 4 directions can each change the position, and the rules for a garage in the grounds of a house are not the same as for the house itself. Put the question to B&NES planning, or whichever council covers the garage, before ordering anything.
Building Regulations can apply as well, particularly where the roof structure is altered or strengthened. Where re-roofing passes the Planning Portal threshold, approval is needed and the insulation may have to improve. Our part is the roofing; the electrical certification belongs to your solar installer.
If the garage is a listed outbuilding or stands in the curtilage of a listed house, speak to the council conservation officers before touching the roof. The listed outbuilding roof guide lists what to ask.
Insulation and the order of work
If you want to insulate the roof as well, plan both together. Insulation and a new covering are best fitted in one operation, with the solar mounts added on top. The page about whether to insulate your garage roof explains the options and the condensation risks of getting it wrong.
The sequence we recommend is simple. Survey the roof and structure. Strip and renew the covering, with insulation if wanted. Check the fall of any flat section and make the flashings and upstands sound. Then let the solar installer fix the array to a roof that is ready for it. Our garage roof replacement service covers the roofing stages and leaves the surface clean, and we can mark where the rafters or joists run so the installer knows where the fixings will hold.
