The different types of solar panel mounting methods
By far the most common way to install domestic PV panels is to mount them directly onto your property's rafters using specialist roof hooks, aluminium mounting frames and clamps. If your property has more than one storey you will need to hire scaffolding in order to gain roof access.
In order to mount the PV array, it is common for installers to remove roof tiles or slates in order to screw the hooks into roof joists. The hooks for the frames are spread evenly in order to ensure weight distribution. The PV panels are mounted on these frames using clamps. The roof tiles or slates are then replaced, and waterproof flashing is applied to the hooks to avoid roof leakages.
For business or farm use, it is also possible to mount PV panels on other roof types, such as those made from corrugated iron. The mounting process here is similar to that for domestic roofs, although it is sometimes possible to attach arrays directly to the roofing material. Special care should be taken here that the roof will bear the weight of the PV array.
Solar panels can of course also be installed on flat roofs using dedicated mounting frames. The advantage of flat roof installations is that in order to optimise system output, PV arrays can be pitched at any angle and made to face due south, regardless of the roof's orientation.
Flat roof installations, do, however, require more hardware, and are therefore costlier. Given, moreover, that they protrude over 20cm from the surface of the roof, such installations will require full planning permission.
Solar PV panels are heavy: they weigh between 15kg and 30kg each, depending on size and manufacturer, with a 3kWh system likely to require 10-20 panels. While most roofs will be strong enough, your roof may need strengthening in order to bear the weight. Roof strengthening can involve a significant additional expense, so it is advisable to check this before installation (your PV surveyor/installer should help you with this).
Ground mount frame for Solar Panels Roof hook & frame for solar panels
Fixed tile hook for solar panels Flat Roof and Ground Mount