Panels can go on pitched roofs, flat roofs and on the ground. The panels are the same; what changes is how they are held in place and what has to be checked first.
Pitched roofs
On a pitched roof, panels usually sit on rails that are fixed to the roof structure with brackets or hooks. The fixings must reach the rafters, not just the tiles, so the position of the rafters is established before the layout is finalised. The roof covering needs to be in reasonable condition: if tiles are loose or the roof will need work soon, it is much easier to deal with that before the panels are on top of it.
Flat roofs
A flat roof usually takes panels on frames set at an angle. The frames are either fixed to the structure or held down by weight, and which is suitable depends on what the roof can carry and on how the waterproof covering is built. Fixings that pass through the covering have to be sealed properly. Wind is a real consideration on a flat roof, so the frame, the fixing method and the position of the array near the edges are all part of the design.
Ground-mounted arrays
Where a roof is not suitable, or a property has land with a clear view of the sky, panels can be mounted on frames on the ground. The questions here are different: the ground conditions and foundations, access for installation and later maintenance, the cable route back to the building, and whether planning rules apply to the site. A ground array is also easier to reach for cleaning and checks.
Safety at height
Roof work is work at height, and it is planned as such: scaffolding or edge protection where it is needed, safe access for people and materials, and a decision not to work on the roof when it is wet, icy or windy. This is one reason the details of the roof are settled before a start date is agreed.
Permissions
Many domestic roof installations in England do not need planning permission, but conditions apply. Listed buildings, conservation areas and flats have additional rules, and a leasehold property may need the freeholder’s consent. If any of this might apply to you, say so when you ask for a quote so it can be checked early.
Planning something like this?
If you are not sure which type of roof or mounting suits your property, email us photos and the address. You can read more on the solar pv installation page.