Yes you can put solar panels on a flat roof. In fact, it’s more common than many UK homeowners often assume! Those panels are mounted differently. The tiles sit directly under the panels flush to a pitched roof. A flat roof typically requires a racking system to pitch the panels at an appropriate angle and secure them from wind.
Here are the key options, as well all of the practical pros and cons to consider for your next property.
Option 1: Ballasted (non-penetrating) mounting
It is one of the widest used typical flat roof systems. Instead of being drilled into the roof, which may invalidate a guarantee depending on what it is for, the panels rest in a mount frame and are held down with weight (ballast).
Pros
Can avoid roof penetrations (makes it easier to waterproof)
Faster installation in many cases
Newer membranes can be a decent option.
Cons
Weighs a lot, so your roof needs to be strong
May use more roof area due to spacing between rows
Option 2: Mechanically fixed mounting
The mounting system is fixed directly to the roof structure this way (using waterproofing and flashing as appropriate). For help with Solar Panel Installation Portishead, contact https://redbridgeandsons.co.uk/solar-pv-panels/solar-panel-installation-portishead/
Pros
Possible to be even more secure in exposed/windy locations
Could have a more condensed placement than ballasted systems
Cons
The penetrations must be done correctly otherwise it will leak.
Not suitable for all roof types or conditions
Option 3: East-west or South-facing orientations
Flat roofs give you flexibility. Most people think panels need to face south but many installers use an east-west array on flat roofs.
South facing tilt for peak system output.
East-wests can distribute generation across the day and deliver higher yields, as more panels may be able to fit on the same roof.
The ultimate “best” choice for you will depend on numerous factors, like your roof size and shading as well as how much power you use during the time of day solar panels produce electricity.
What to consider before installing:
A reputable installer will assess:
Roof condition and waterproofing (If necessary repairs first);
A major concern with ballasted systems is structural loading
Shadowing and obstructions (e.g. vents, skylights; buildings, neighbours)
Exposure to wind (by coast, on top of hill, in the open etc)
Others (scaffolding, edge protection etc.,)
The practical takeaway
Flat roofs can handle installing solar panels and lots of them. The proper mounting allows your roof to stay undamaged, is code compliant safe, and ensures best performance per pound.
When thinking about flat-roof solar, see if the installer can show you a plan of how it would be laid out as well as the roof loading calculation and what they will do to ensure waterproofing.
