Nowadays, everyone should know that solar panels, as well as a source of renewable energy, can actually make a home money through government subsidized feed-in tariffs. But what if home has a flat roof? Can solar panels be effective and safe when installed on a flat surface?
The answer is yes. But there are many things to take into consideration when planning a PV installation on a flat roof.
As UK homeowners know, planning permission effects most home alterations. Solar panels are listed as a permitted development in the UK, which would usually mean no planning permission is required. However there are rules that must be adhered to, even with permitted development rights in play.
When installed on a house with a sloped roof, the PV panels must not protrude more than 20cm from the surface of the roof. But on flat roof, the panels need to be placed at an angle to maximize exposure to sunlight, and to prevent rainwater from gathering on the surface.
The optimum angle is around 25 – 30 degrees. This means that the panels will almost always be over the 20cm limit.
Therefore if the owner of a flat roofed home is planning on investing in solar, planning permission will almost always be required and the best solar companies can usually take care of the process. It is also worth noting that permitted development rights can vary from council to council, if they issue an article 4 direction. These directions are usually put in place to protect the character of an area, and are most often issued in conservation areas.
For safety reasons, PV panels must be secured to the roof in the correct way. Britain's temperamental weather can make the exposed surface of a roof an incredibly windy place. On a flat roof it is usually best to ballast the panels, as opposed to bolting them into the surface of a roof, which could potentially damage the weather proofing of a building.
An structural engineer will calculate the wind load of a roof, and ballast the panels in a safe way, using the correct amount of weight to counter the weather in any given area.
Be aware that flat roof installations tend to not last as long as the 20-25 year estimate that applies to installations on sloped surfaces, although they still have an impressive life span. Repairs may be needed more regularly, as roofing laminate may have to be replaced, and ballasts may need to be reconfigured.
Photovoltaic solar panels are not just good for the environment. An investment now will double a homeowners money over a 25 year period, showing that feed-in tariffs can actually increase a home's income, as well as cutting an average of £ 70 a year from energy bills. So all in all, spending the time and money installing PV panels on a flat roof is still an extremely worthy investment.