Flat roofs are among the preferred surfaces for installing photovoltaic systems (PV). The reasons are obvious: installation of PV systems on flat roofs is relatively simple, and projects can be carried out in a short time and at low installation costs. PV roofs also benefit from high energy resale values which are legally protected for the next 20 years.

While these systems are ecologically sound investments with attractive returns, they have a problem. Roofs already top the list when it comes building elements which experience the most damage. Add a retrofitted PV system, and the roof can be put at considerable additional risk. With that in mind, and the fact that leaks in the roofing may seriously jeopardize the financial return on the photovoltaic system, a roof monitoring system which guarantees long-term security for solar roofs makes absolute sense.

In the search for sources of liquidity, building owners are increasingly leasing their rooftops to PV system operators. These companies build and run PV systems on the roofs, and in return, the owner gets the lease income. The production of renewable energy on the leased roof is often planned for a minimum of 20 years, which also means that the roof has to last at least that long.

This is exactly where the risk is highest for all concerned, as retrofitting, construction and operation of the PV system leads to additional stress and very probable damage to the roofing membrane. At the same time, an in-place PV system makes locating damage more difficult, if not impossible. If the roof must be repaired or, worse, completely restored during the operational phase of the PV system, electricity generation must inevitably be stopped. Additonally, the costs of dismantling and rebuilding the PV system are added to the costs of restoring the roof. Where PV systems are operated on leased flat roofs, costly disputes between building owners and facility operators are virtually guaranteed.

The just-released insurance report from the German Federal Ministry of Transport, Building and Urban Development (BMVBS) pointed out that „roof damage in general is the most frequent claim occurance, and...damage to flat roofs is the most frequent occurance of all roof claims.“ It is not the obvious damage from storms or hail, as one might imagine,but rather small perforations and holes in the relatively thin waterproofing membrane which allow – often for years - water and dampness to penetrate into the building, causing extensive damage.

All of the problems described above can dramatically affect the profitability of a PV installation and can literally take a project from profit to loss. Thus, one must have a realistic strategy to keep a long-lasting and verifiably watertight roofing envelope as the foundation for a reliable and assured return on investment.

Progeo makes this possibility a reality through the combination of unique roof leak monitoring systems for photovoltaic installations on flat roofs.