Mounting muck-ups

Steve Pester, BRE, exposes ongoing poor practice in mounting PV panels

With the government’s final decision on changes to support mechanisms for solar not yet announced, I am inclined to steer clear of crystal ball gazing (however tempting). To use a heating analogy, let’s just hope for a slight turning down of the thermostat rather than a scrapping of the whole heating system.

So, I will take refuge in a techie subject, and a different kind of solar support. In our travels over the past couple of years, providing quality inspections and fault-finding services, we have seen quite a number of roof-mounted PV installations that have panels incorrectly mounted. The usual problems are:

  • Unevenness in the alignment of panels
  • Incorrect positioning of mounting clamps
  • Clamp screws with incorrect or random torque settings
  • Mounting rails too short or too long
  • Panels too close to roof edges
  • Tiles lifted by roof hooks
  • Insufficient roof hooks for the calculated wind loading
  • Split rafters through ignoring screw diameter / timber thickness rules, or misaligned screws

Then there are design decisions that have been left to chance, for example:

  • No wind loading calculations, so the number of roof hooks required is just guesswork
  • No effective assessment of roof structures

With the FiT rush that is now under way, it is easy to let installation quality slip in favour of maximising installed capacity. But with the solar industry still fighting to be taken seriously by the powers that be, it is essential to be seen as a capable and highly professional sector. Let’s keep a focus on quality – and avoid return trips to site!