Typically domestic solar PV systems are mounted on a pitched roof of the home, as close to south as possible. However this does not mean that all systems must be mounted on pitched roofs. Some homes have a flat roof, other have a shaded roof but plenty of space in the garden, some may have a garage or shed in the garden that can be used.
There are numerous different ways to mount panels, detailed over the following sections.
On roof – Slates or tiles
This is the most common mounting method for domestic properties. Here, stainless steel roof hooks are fixed into the rafters of the building and railing is then attached to these. The panels are then clamped to the railing. This fixing method has been honed over the past 13 years by Conergy on systems across the globe. Different roofing tiles will have different roof hooks used dut to the shape of the tiles themselves. Equally a different bracket is used for slate roofs.
Using our engineering background and experience of the UK solar industry, we have worked with Conergy, notably on the pitched roof fixing method to develop the mounting systems further. This has involved adapting the roof hooks especially for the types of roof tiles and construction methods employed in the UK.
On roof – Metal or concrete corrugated roofing
A common roofing material on sheds, farms and warehouses, this is a material we have vast experience of through our thriving commercial business. There are several options here for fixing panels to these types of roof. if concrete roofing is used, and there are wooden beams supporting the roof, we can drill through the material with a self sealing stainless steel screw which we can then mount rails and panels to.
Metal corrugated roofing can be fixed to with either a clamp riveted to the top and sides of the raised sections, or of the material is thicker than 0.7mm then the railing can be fixed directly to the material itself with rivets. This is a much simpler and faster method than the others, so if you are thinking of re-roofing or building a new farm building we would suggest this roofing material for the savings it will offer.
An in roof PV system can be a visually appealing alternative to mounting the panels on the roof. Depending on the thickness of the roofing tiles or slates used, the panels can appear set into the roof, similar to a velux window. In-roof mounting systems are more expensive than other pitched roof systems, because of the extra materials required to maintain the weather proofing of the roof.
Here a tray, usually metal or rubber is set down across the area the panels are covering. Fixings then attach the tray to the battens across the roof (battens run across your roof and are fixed into your rafters) and then the panels to the tray. We stock in-roof mounting kits from both Conergy and Ubbink.
There are some limitations with in-roof systems you should be aware of:
- They are not compatible with rosemary tiles as the tiles are too small to sufficiently overlap the trays to provide waterproofing.
- There must be a boundary of 600mm around the edge of the array to maintain the overlay discussed above for waterproofing purposes.
- Finally because of the tray fixed into battens, you require slightly thicker than standard battens.
We strongly advise only opting for this type of system if you are either re-roofing or building a new property.
Flat roof systems are a great option if you have limited pitched roof area but an extensive flat roof available as they allow you to optimise the orientation and pitch of the panels. They are more expensive than a pitched roof system, as there are more components to the mounting system, a structural survey is needed to check the roofs integrity and full planning permission is needed for domestic systems.
There are two methods to fix panels to a flat roof, and again here, we use Conergy mounting frames to fix the panels to. The first is to ballast the mounting frames to the roof of the building; here the panels are fixed to A Frames. The A Frames are then ballasted, usually with concrete slabs or lintels, by a set weight pre determined by a wind loading check on the building taking into account location, height and prevailing wind. This method is favourable for retro fit installations as there is no penetration of the roofing membrane, meaning any warranties of the roof covering can easily be maintained.
If the roof is not strong enough to take the additional weight of the panels and ballast, the second method is to fix wooden up-stands to the roof. This method is also often chosen when a new build is occurring as it reduces the stresses on the roof. The wooden up-stands are fixed to the joists in the roof and then covered with the chosen roofing material. The A Frames are then fixed to the up-stands and any fixings weatherproofed to ensure the long term integrity of the roof.
After testing numerous different ground mounted frames, we decided upon developing and manufacturing our own frame, Atlas. We have used the structural engineering expertise within the company and our experience developed over 5 years of installing PV systems across the UK to design our own frame capable of withstanding the harshest conditions in the UK. The advantages of our frame lie in the faster delivery time to site and a reduced system cost as we are cutting out the middle man. It is also engineered and manufactured in England.
Ground mounted arrays are a great way of maximising the output from the panels as they allow you optimise the orientation and pitch of the panels.