Saving energy and costs
“With the quick scan, Iv-Bouw can add value for its clients, both in terms of costs and promoting sustainability”, says Etienne Boender, Branch Manager at Iv-Bouw in Delft and initiator of the quick scan method. The quick scan answers two main questions: ‘Is the roof structure able to support the extra load of solar panels, and if so, how much extra load?' And: 'which additional measures are required to install a PV installation should the roof structure be insufficient?'

A staged approach
The quick scan is performed in four phases. This 'staged' approach is deliberate and can help limit the quick scan costs because it may already be apparent what is and isn't possible during the first stage. Iv-Bouw first examines the residual load-bearing strength of a roof based on reduced load factors. Thus, the age of a roof structure is partly a determining factor for this investigation.

Next, we map out any residual strength of the roof structure based on structural analysis. This is done for the main structural bearing elements, such as main beams and columns. Therefore, the strength and potential load are calculated critically. “We examine the existing load, including the steel sheets, insulation material, roof covering, etc. These are all loads – no matter how small – that must be included in the calculation. And based on the calculated values, we can determine the remaining capacity. We do this via structural calculations”, says Etienne. Iv-Bouw has all the specialisms in-house to conduct a thorough assessment in which colleagues from E&W (building-related installations) and structural engineers closely collaborate.

Next, if the former step results in enough residual strength of the main structure, we explore beyond the roof and determine which connections are present and the sufficiency thereof. Additionally, the condition of the roof sheets is examined, and we assess whether further examination is necessary.

The final step is only required when the results of the second or third step show that the main structure or the secondary elements cannot withstand the additional loads. In this case, the structural measures are designed to strengthen the roof structure.

A practical example
Iv-Bouw recently conducted a quick scan on behalf of Landgoed Leusderend, a majestic country estate amid forests, sports fields and hiking trails, where various companies rent office space. The quick scan, in which a structural test was also performed, revealed the main supporting structure could bear the additional load of the PV installation. This concerned the steel profiles in the roofs but not the roof sheets. The roof sheets were too weak to withhold any additional load. This calculation was made in accordance with the renovation requirements of NEN8700. So, in this case, the installation supplier would need to construct a structure directly supported by the steel profiles.

Still much to gain
In recent years, the Netherlands has seen considerable growth in the number of solar panels. As a result, the Netherlands is slowly creeping towards the forefront after years of being at the bottom. But there is still much to gain, and Iv-Bouw aims to contribute by performing easily accessible quick scans.

There are currently more than 1.5 million households in the Netherlands with solar panels on the roof. This may sound like a lot, but in reality, approximately eighty per cent of (private) roofs are not yet used in this regard. Even when it comes to business premises, the majority do not yet generate solar energy by covering the roof area with solar panels.

Client demand
Etienne explains: “When renovations take place, a roof is not always seen as more than a roof over one's head. But actually, it has much more potential.”

Iv-Bouw wants to offer help and advice with a straightforward approach to companies and property owners struggling with this uncertainty. “Until now, we've offered this service, but never up front. We now want to do this, show what we can achieve, and establish a standard procedure for clients.”

We don't turn it into rocket science
Iv-Bouw has years of experience and expertise in performing quick scans. We also have in-house specialist knowledge of building structures and installations. This knowledge is essential for determining whether roof structures can support solar panels. Etienne: “You must understand structures and have knowledge about load distribution and the associated risks of renovating existing structures.”

But he also states that a quick scan of a roof doesn't have to be rocket science. “Roofs are generally not the most complicated of structures. So, we always begin simple, and as a quick scan progresses, it becomes more complex. Our calculations start by hand and can grow into a more in-depth calculation with the help of structural software to assess a roof accurately.”

However, a standardised quick scan method is new, no matter how logical the necessity and demand may seem. Etienne: “It also suits Iv-Bouw, and Iv in general, to observe these opportunities in the market and pragmatically devise a solution to close the gap.”

While the energy transition and the climate goals to be energy neutral by 2050 are being accelerated, the quick scan is a financially sustainable way of getting more out of a roof than is considered possible.

“Our experience has shown that the question of whether it is possible can often be answered with ‘yes’. The quick scan enables us to determine the potential of a roof, which is often more than assumed.” •