Pigeons love these types of structures with the open wooden beams and the pillars that all provide plenty of roosting and protected nesting sites. 

3/4" tan netting was installed to the underside of the wooden beams to keep out the sparrows as well as the pigeons

Hog rings hold the netting to the cable system so that the net will stay tight and not blow or move around if a wind blows through

A zipper being installed to allow access to the fire sprinkler head if it ever needs to be replaced

Zippers allow access behind the netting for any lights or other equipment that may need to be reached later.

The finished product is nice and clean looking, most people walking up to this area will not even notice that the net is installed here - way better than all the pigeon droppings they use to have to walk through