There is much cross-bracing on the top of fuel station canopies which makes fixing modules to the sheeting impractical and ill-advised for two reasons:
Firstly, any shading over the modules needs to be considered in the design process, as this would curtail production.
Secondly, the sheeting seen from below is top hung, so applying load to the sheeting from the top would eventually pop out the fixations to the I-beams.
We decided to go above the mess and span between the main columns. This meant we had a more robust solution and one that would offer greater structural stability because the loads would be transferred down the main members.
It was also fast to install. Really fast. The drilling of a few holes in the main I-beams, the attachment of our risers and then fixing our purlins and lastly the modules meant that within 1.5 days we would finish our scope of mechanical supply and erection including modules.