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As manager of BMI Monier's Roof Service Department, Jan van Leeuwen sees every day where things can be improved on the roof. For eighteen years he has been closely following developments. He sees two main bottlenecks, both of which are mainly caused by time pressure and lack of expertise: The cost of failure in the construction industry will not go down and the number of incorrectly installed PV panels on the roof is increasing.
For both, he sees a clear solution: working with BIM that allows the roof system to be virtually built in detail in advance, including any PV panels, as well as choosing certified roofers with expertise in installing PV panels.
During the past six months, Van Leeuwen, together with colleagues from other technical centers of BMI Monier, has been making BIM models of all types of roof tiles. But not only the tiles, also all system components such as fasteners, eaves profiles and roof foil have been put into BIM. With the help of BIM, the roof system can therefore be constructed completely virtually with any challenges resolved in advance. This saves time during construction, avoids ordering too much, or the wrong materials, increases quality and prevents mistakes. Ultimately, building a roof system modulated in advance in BIM is cheaper in the long run and fully guaranteed. According to Van Leeuwen, the increasingly common construction method of working with prefabricated roof elements combined with a BIM-modulated roof system is a fast and cost-effective method of delivering an excellent roof. Unfortunately, knowledge of BIM is not yet uniform in the construction world. There is much room for improvement so that construction costs can be reduced and productivity increased.
According to Van Leeuwen, installation of PV panels on the roof goes wrong quite often. Once the roof is covered, the contractor or a PV installer afterwards attaches PV panels to the roof. Often this is the closing item of a project and the cheapest solution is chosen. This can mean that without knowledge of the roof system, fasteners are installed that undermine the quality of the roof system and make the PV panels insufficiently wind resistant. Frequently, the installation does not meet the applicable NEN 7250 standards. Roofers, after such an installation - in which they themselves are not involved - only give a warranty on half of the roof. The part without PV panels. That the quality of installation of PV panels on the roof lags behind is also shown by a recent TNO study. Fire on the roof for 80 to 99% is caused by improper application of connectors. Combined with application of flammable foil, the roof becomes a major risk factor. According to Van Leeuwen, this clearly indicates that there is a lot wrong with the quality of installation on the roof. The TNO study also reveals that personnel are selected for lack of fear of heights rather than for installation knowledge. As an additional problem, Van Leeuwen sees that when installing the PV installation on the roof separately, no one oversees the total. PV panels and roof system are seen as separate parts. With all its consequences.
The BIM modules for the roof provided by BMI Monier include PV panels and the fastening components. Based on the desired energy yield, this makes it possible to determine in advance exactly where and how many PV panels should be placed on the roof and how they can be attached in the best way. By having this entire system installed by the same approved party, the roof warranty for the entire roof system remains intact.
Jan van Leeuwen
The employees of BMI Monier's roof service department possess all the knowledge necessary to build a good roof system. This is partly because they think in systems here and not in individual components. The roof is a system and is therefore also tested as a system in BMI Monier's technical centers. The watertightness of each roof system is extensively tested in our own wind tunnels, the fasteners we develop ourselves are tested for all possible loads and foils and other roof system components are tested in our own laboratories, thus guaranteeing the performance of roof systems. The tests take place with wind forces and thaw/freeze cycles that substantially exceed the standards applicable in the construction industry. Van Leeuwen and his colleagues share this knowledge daily with architects, contractors and roofers. Moreover, a number of employees from the Roof Service Department are members of various standards committees. In this way, the knowledge of Monier BMI is shared with as many parties as possible. With only one goal: to ensure that every roof is built with dedication and expertise.
