It is one of the most common things people ask us before they commit to anything: is my roof actually up to this? It is a fair question. Solar panels are designed to last 25 years or more, and they will be sitting on your roof for all of it. If the roof underneath is coming to the end of its life, you do not want to find out three years after the scaffolding came down.
The short answer is that most roofs in Dorset, Hampshire and Wiltshire are perfectly fine for solar as they are. But some are not, and we would rather tell you that at survey stage than take your money and hope for the best. Here is how to work out which camp you are in.
How old is too old?
There is no magic number, but the useful way to think about it is remaining life rather than age. A concrete tile roof typically lasts around 40 to 60 years. Clay tiles often go longer. Natural slate can run well past a century if it has been looked after, while the cheaper fibre-cement slates fitted in the 1970s and 80s tend to give up much sooner.
The rule of thumb we use: if the roof has fewer than about ten years of life left in it, it is worth dealing with the roof first. Solar panels can be taken off and refitted later, but you are paying for scaffolding, labour and a day or two of disruption twice over, and there is no good reason to do that if you already know the roof is on borrowed time.
If the roof has 15 or 20 years left, fit the panels. Panels actually shelter the tiles underneath from UV, rain and frost, so the covered area often ages more slowly than the rest of the roof.
What we actually look at on a survey
A proper roof assessment is not someone squinting at a satellite image. When we survey, we are checking:
- Tile or slate condition — cracked, delaminating, flaking or heavily weathered coverings. A handful of broken tiles is a quick fix; widespread delamination is not.
- The battens and felt — this is the layer most homeowners never see. Old sarking felt that has gone brittle, or battens that have started to rot, will not hold mounting hooks reliably.
- Rafter size and spacing — panels and mounting rails add weight, and more importantly they add wind loading. We check the timbers can take it.
- Signs of movement or leaks — sagging ridge lines, staining in the loft, daylight where there should not be any.
- Flashings, valleys and chimneys — the places roofs almost always fail first.
- Access and safety — how the scaffold will go up, and whether anything about the layout makes the job awkward.
Because our installation teams are employed by us rather than subcontracted, the people who survey your roof are part of the same business as the people who fit the panels. There is no incentive for anyone to wave a marginal roof through and leave someone else to deal with it.
Roof coverings that need a different approach
Some roofs are not a no, but they are a “let’s talk about it”:
- Thatch — panels cannot be mounted on thatch. A ground-mounted array or an outbuilding roof is usually the way forward.
- Asbestos cement sheet — common on older agricultural and light industrial buildings. It can sometimes be worked with, but it often makes more sense to replace the sheeting as part of the project.
- Flat roofs — genuinely good for solar in many cases, but the roof covering has to be sound and the mounting method matters. We have written separately about what works and what doesn’t on a flat roof.
- Interlocking pantiles and unusual profiles — fine, but they need the correct hooks and a bit more care at fixing points.
- Listed buildings and conservation areas — the roof may be fine; the consent is the harder part.
If the roof does need work
Two sensible options. The first is to re-roof and fit solar at the same time. This is by far the most efficient sequence: one lot of scaffolding, one lot of disruption, and the roofer and the solar team can coordinate on fixings and flashings. If you were already planning a re-roof in the next couple of years, bringing it forward to line up with a solar install is usually the better call.
The second is targeted repair. If it is a dozen cracked tiles and some tired flashing rather than a failing roof, that gets fixed before we start and the install goes ahead as planned. We will tell you honestly which situation you are in.
What we will not do is fit panels onto a roof we do not think will hold them properly. An MCS-certified installation has to be safe and weathertight, and our workmanship warranty means we would only be creating a problem for ourselves.
Before you call anyone
You can get a long way on your own. Have a look in the loft on a bright day for daylight, damp patches or sagging. From the ground with binoculars, look for slipped or missing tiles, moss build-up in valleys, and anything that looks out of line. If you have had the roof done in the last twenty years, dig out the paperwork.
Then get a feel for whether solar suits your property at all before anyone visits. Our free suitability checker asks five questions about orientation, shading and how you use electricity, and our free size estimator gives you a sensible kWp range for your household. Neither asks for payment details or commits you to anything. If you want to know what the install itself involves, we have set out what actually happens on the day.
Talk to a local installer
If you are not sure whether your roof is up to it, the quickest way to find out is to have someone look at it properly. We are MCS-certified, based in Wimborne, and we cover Dorset, Hampshire, Wiltshire and the surrounding counties with our own employed teams. Request a free, no-obligation quote and we will give you a straight answer about your roof — including if that answer is “not yet”.