Solar is a booming industry in South Africa and this will probably continue for at least the next 5 years. This is generally not because of concern for climate change and a drive towards renewable energy sources. Instead it’s a necessity due to the beleaguered Eskom, South Africa’s national and state owned power producer. ‘Load shedding’ is the term which has been coined to describe planned power outages according to a pre determined schedule. It makes sense from a cost and convenience point of view for industry and commerce to invest in solar panels to reduce the reliance on the main electricity grid. There are many attractive options on the table in terms of financing and leasing and these investments pay off within just a few years. Financially it’s not as appealing for the home owner, but for the wealthy who can afford it and is tired of the inconvenient power cuts, it’s a good option and is becoming quite popular.
Installing solar panels on roofs makes a lot of sense. Most roof structures are designed to handle the extra load without any further modification. It is also free and unused space, do why not use it to best advantage! The only drawback is that sometimes solar panels are installed onto roofs which are leaking or in poor condition. Once the solar panels are laid, access is extremely difficult in the event of roof maintenance bring required.
The most common roofs are metal, flat concrete and tiled coverings. Herewith an overview of each roof type, what to look out for prior to laying of panels and what repairs may be required.
The first thing common to all roof types is to ascertain if there are any leaks from the roof sections where the panels will be laid. It may also be prudent before solar systems are installed, for either a professional roofing contractor or independent roofing consultant to inspect the roof to determine soundness before any installations are done.
Tiled roofs
This is probably the easiest roof to inspect and repair should this be necessary. Common problems could include:
- Cracked and broken tiles. These should be replaced.
- Cracks on roof ridges. This should be repaired using the Aquagard roof ridge sealing method.
- Blocked valley flashings. Tiles along valleys may need to be shifted and cleaned out to remove any dirt or leaf litter. It is recommended that there is a gap of 50mm wide between the tiles down the length of the valley. It will tend to block up less easily and also makes access and maintenance more simpler.
Special brackets are used to secure the solar panels and these are generally quite leak proof and trouble free.
Metal roofs
This is a roof type which is most common for mounting of solar panels. However there can be various challenges.
- If there is rust or corrosion, this would definitely need to be treated before solar panel installation. It is recommended that a high quality roof paint be used that would carry a minimum of a 10 year guarantee. Coatings most suitable would be high end acrylics, polyurethanes or epoxy aluminum.
- General maintenance should include that there are no holes, and roof screws should be replaced or sealed.
- Any waterproofing membrane to overlaps of roof sheets must be removed. This is incorrect waterproofing and will cause rust and leaks in the future. Depending on whether there are leaks in the area and the slope of the roof, installation of butyl sealing tape between the roof sheet overlaps is recommended.
- Other items in the vicinity which can probably still be accessed, but should be repaired and inspected anyway, include flashings and roof ridges.
- If the panels will traverse back flashing, this should be inspected and repaired as necessary.
Mounting of solar systems on Kliplok type roofs is very successful. A bracket is available from the major roofing suppliers which is used to clamp onto the ribbed profile of the roof sheet without penetrating the roof. The extra ballast also helps to prevent unclipping of sheets and subsequent wind blow offs, as very occasionally happens to these roofs.
IBR and corrugated roof types pose a much greater challenge when it comes to solar system fitment. The panels have to be secured to the roof sheets using brackets and screw fastners. The design of the brackets and waterproof seal is critical in ensuring that water penetration does not occur.
Flat concrete roofs
Flat concrete roofs are also popular and ideal for solar panel installation. Unless the waterproofing has been recently installed using a high end torch on product, it is probably best to apply a new waterproofing system to at least the roof section where the panels will be laid. Waterproofing systems which will require the least amount of maintenance are preferable. This could include double layer torch on systems. TPO may also be a good option.
It is not recommended to screw fix brackets through the waterproofing layer. Other options are ballast such as water containers or concrete lintels/blocks laid onto the solar panel support frame. Concrete plinths can also be cast on the waterproofing. New waterproofing can be used to seal over the plinth and the frame secured onto this. If there is no other option for whatever reason to screw fix the frame through the waterproofing, the frame structure should have a large metal base plate onto which a new waterproofing layer can be sealed.
