Solar panels – what lurks beneath?

Between 2012 and 2017 the UK and Europe saw a surge in the domestic use of power generation from solar panels (see this article for more information). It has tailed off a bit, but the chances of buying a property with solar panels is now a lot greater than it was a decade ago. You might also want to sell a property with solar panels. So, what do buyers and sellers of houses with light absorbing power generators need to consider?

Probably the first consideration should be a legal one as the panels could potentially affect any mortgage agreement your buyers may be arranging. If you have purchased and installed the panels independently, you should be fine, but if you joined one of the schemes where solar panel companies rented the space on your roof for discounted supply of panels and for the feed-in tariff then you will need to make sure there are no issues with the lease and that the paperwork carries over from seller to buyer. It is possible that there may be additional administration and legal costs involved in doing this.

Collier Stevens is aware of problems associated with these long-term leases that may have been entered into without consideration of any longer-term problems. These can include complications with future sales, ability to remortgage and even party wall agreements.

solar panel problems found on a building survey

Are solar panels, and where they are fitted, covered by the Party Wall Act?

If you are doing work that requires a notice to be served to a neighbour and they have solar panels, you may need to serve a notice to the Solar Panel company if they lease the space on the roof. This is because they may have an interest of greater than 12 months in part of the neighbouring property which means they are an “owner” for the purposes of the Party Wall etc Act. This might affect loft conversions, but also oddly, adjacent excavation which requires notice to all owners within 3m of the work.

The crucial building survey

For a prospective buyer, a proper survey is essential. Depending on the age of your property, a HomeBuyer report may be appropriate, but more often a full building survey is recommended. When we undertake property surveys, solar panels are always on our list of matters to consider. They can hide any number of problems and also be a cause of some too. Sometimes we are asked to give advice on whether the roof is capable of supporting solar panels in the future.

a diagram showing how solar panels feed electricity through your property
This diagram demonstrates how solar panels are connected to your property’s electrical infrastructure.

Can a roof covering be inspected properly if there are solar panels?

Where a roof is covered with solar panels, it can be difficult for us surveyors to inspect the exterior of roof slates and tiles, but we can draw strong conclusions from the surrounding visible coverings.

Hopefully any issues with a roof would have been resolved before the panels were installed and the panels will act as further protection against the weather for the roof. We always take a thorough look inside the loft space for any leakage and check accessible fixings on the rafters and the routing of any cabling.

Can solar panels damage my property’s roof?

If the panels have been installed properly by a reputable installer they should have checked the integrity and strength of the roof in the first place but some damage can occur to the coverings during installation – slates and tiles can be broken and loose tiles may not be properly reinstated. Some discolouration can occur below the base of the panels, but this is usually aesthetic and not structural.

Older roofs will not have been designed to modern structural standards and the rafters and timbers may be at, or passed, their design limits. This can often be the case if heavy concrete tiles have replaced slates and the structure has not been strengthened. The ability to support additional load may not be there, and it’s not just the weight of the panels (which are actually quite light), but also wind lift. Where wind blows under the panel between the panel and the roof covering, this can cause the panel to try to ‘pull’ off the roof and this also causes a load on the structure. Similarly, modern prefabricated truss roofs may not have been designed to accommodate significant additional loading.

Solar panels are usually fixed to a bracket that is fixed to the rafters. This is often done by removing tiles or slates and whilst there are some excellent fixings and few issues with weathering, we have come across some very poor installations where slates have been cut and holes ‘sealed‘ with mastic and self-adhesive waterproof tape. Occasionally we have found loose panels.

Sometimes, slate will need to be drilled through to ensure the fixing is made securely – again, this needs to be done with care and by an expert. Consideration should also be given to older synthetic slates (1950s and 1960s) which can contain elements of asbestos.

If panels are fitted to flat roofs they are usually required to be at an angle to catch the sun – there need to be checks made for prevailing wind direction and the fixings must be strong enough to withstand heavy winds. This must be a consideration for any type of roof, but especially where they are at an angle.

Do solar panels need regular maintenance?

The solar panels themselves need very little maintenance and should last 25 years – they’ll want cleaning a couple of times a year and might need parts replacing, but generally the company you purchase the panels from will offer a maintenance scheme.

Are there different types of solar panels?

It is not just power generation that makes use of solar energy. Sometimes solar is used to supplement domestic hot water and space heating. Similar principles apply, but quite often these panels are heavier. It is significantly less likely that such panels will be installed on a lease basis.

Looking forwards

There are some interesting future developments, most notably the introduction of solar roof tiles and slates which overcome the need for separate panels. Tesla seem to have been in the lead, but other firms are developing equivalent products. We expect the use of these in both new build and roof covering replacement to become more widespread over the next few years.

Find out more

If you want to find out more about solar power, the history of its use and the latest developments, take a look at this more in-depth article by The Switch.

If you are buying a property with solar panels, or you’re thinking of having them installed, get in touch with us for a full building survey or party wall advice.

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