One of the first questions business owners ask us is whether their roof is actually suitable for solar panels. It’s a fair question – and the good news is that the vast majority of commercial roofs in the UK can support a solar installation. But there are a few things worth checking before you get too far into the process.
Here’s a straightforward guide to the main factors that determine whether your roof is a good fit for solar.
Roof Orientation: Which Way Does It Face?
In the UK, south-facing roofs receive the most sunlight over the course of a day and will generate the most electricity. However, east and west-facing roofs still perform very well – typically generating around 80–85% of what a south-facing roof would produce.
In fact, for businesses that use electricity fairly evenly throughout the working day, an east-west split can actually be beneficial. East-facing panels generate more in the morning, west-facing panels generate more in the afternoon, and the result is a smoother, more consistent supply that better matches your usage pattern.
North-facing roofs are the only orientation we’d generally advise against, as they receive significantly less direct sunlight and the returns are harder to justify.
Roof Pitch: How Steep Is It?
The ideal pitch for solar panels in the UK is between 30 and 35 degrees, which happens to be the most common pitch for commercial and industrial roofing. But panels perform well on a wide range of angles.
Flat roofs are actually very common on commercial buildings, and they’re excellent candidates for solar. We mount panels on angled frames that tilt them to the optimal angle, giving you the best of both worlds – a flat roof’s easy access and a tilted panel’s efficient generation. Flat roofs also offer the flexibility to orient panels in any direction.
Roof Condition: Is It Structurally Sound?
Solar panels have a lifespan of 25 years or more, so it’s important that your roof is in good condition before installation. If your roof is due for replacement or significant repairs in the next few years, it makes sense to address that first rather than removing and reinstalling panels later.
Structurally, solar panels are lighter than most people expect. A typical installation adds around 10–15 kg per square metre to the roof load, which most commercial roofs can handle comfortably. During our site survey, we assess the roof structure to confirm it can safely support the system – and if any reinforcement is needed, we’ll flag it early in the process.
Shading: Are There Obstructions?
Shading is one of the biggest factors that can reduce solar panel performance. Trees, neighbouring buildings, chimneys, satellite dishes, and rooftop plant equipment can all cast shadows that affect generation.
A small amount of shading at certain times of day is usually manageable – modern panel technology and smart inverter systems can minimise the impact. But significant shading across a large portion of the roof for much of the day will reduce your return on investment. During our survey, we use specialist tools to map out shading patterns throughout the year so we can design around any obstructions.
Available Space: How Much Room Do You Have?
As a rough guide, you need around 15–20 square metres of unobstructed roof space per 4kW of solar capacity. A typical 30kW commercial system requires approximately 120–150 square metres – that’s a relatively modest area for most commercial and industrial buildings.
We also need to account for access walkways, setback from roof edges (for safety and wind loading), and space around any existing rooftop equipment. These requirements reduce the usable area slightly, but we factor all of this into our system design.
Not Sure? We’ll Check for You
The easiest way to find out if your roof is suitable is to have us take a look. Our site surveys are completely free, and we’ll give you an honest assessment – including whether solar makes financial sense for your particular situation. If it doesn’t, we’ll tell you straight.
Get in touch with Joe Solar today to book your free roof assessment and find out how solar could work for your business.