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Does My House Have The Right Roof For Solar Panels?

Renewable energy for houses has finally become affordable and an investment in solar photovoltaic panel systems will give you power for up to 30 years.  A regular question we get is “What type of roof works best with solar panels?”  Let us answer that for you here:

Basic Requirements

If you are doing a new build then take advantage of the blank slate and orientate your biggest roof towards the sun.

Next decision relating to orientation is keep that roof away from shade casting neighbouring houses, trees, chimneys, etc. Consistent shading on even one of the panels will affect the efficacy of the entire string of panels. This can be solved with micro-inverters on each panel and we highly recommended this.

The pitch of your roof aids as well, with between 30 and 45 degrees being a good option.  A-Frame homes can make panel installation difficult and might compromise panel efficiency.  Solar panels actually work best when angled at a degree equal to the latitude of its location.

Different Roofing Materials

Virtually any type of roofing material is suitable but not for all roofs. Here are few general pros and cons of different types of roofing materials.

Asphalt shingle roofs are widely used and installation of them is straightforward. Drilling is made into the roofing with 2x4s for the panel brackets and the holes are waterproofed. A drawback is the lifespan of these shingle types, which is usually up to 18 years maximum.  Solar panel warranties are valid for 25 years. You will replace that roof and the panels will have to be taken down and be reinstalled without hopefully damaging them. 

Clay tile roofs, slate and concrete tile roofs unfortunately can create a generally labor-intensive, high cost installation.  Portions of the clay tiles may need to be removed to access the studs. Sometimes the clay tiles can be replaced around the mounting rack but custom-sized hooks and flashings are required to cover up the holes. Unprofessional installation can lead to damaging water leaks. The same concerns relate to both slate and concrete tile roofs.

Flat roofs of concrete and/or EPDM (rubber membrane) are highly suitable for solar panels for house. A metal racking system will be needed to prop up the panels but this allows for the optimum efficiency angle to be achieved which is brilliant. Furthermore a ballast system can be used which avoids penetrating the roof and EPDM.

Metal roofs are the best fit and are hugely popular in Australia. They offer a solid surface and some are fully recyclable which supports your sustainability ethos. Panel brackets can be clamped securely to the raised seams of raised seam metal roofs. If holes are drilled, there are many cost-effective waterproofing sealants for metal roofs. These roofs also last for up to 80 years.

Solar roof shingles are small solar panels embedded in each roof tile. Several options are arriving on the market including Tesla and three-in-one roof (with added insulation and wind protection). These are ideally suited for building-integrated photovoltaic (BIPV) rooftops. The three-in-one tile is better insulated and operates at optimum temperatures.

Additional Considerations

You, or your staff, will need to access the roof to clean your panels so consider access as well as snow guards if relevant to your location.