BSU Roof Top Garden

Boise State University Student Union Building has begun making some beautiful changes. The roof itself has had some water problems and they were exploring the idea of how to combine fixing the roof leaks with making a roof top garden that they could use to grow vegetables for use in the cafeteria.

With the help of Upson Company in Caldwell, they were able to fix the leaking roof and have beautiful area for the gardens.

With this project Upson Company had some interesting but all to common issues. Initially the roof top was concrete with an expose aggregate surface, over time water had leaked through the aggregate and concrete. Coatings can be associated with or confused as a roofing product, they are only classified as, and some carry ICC approvals but only as traffic coatings. Here are some pictures of the resulting problems with the coatings used. The first one used (it appears there were two different ones used over time) was a combination of sand and a urethane type coating. The aggregate was a very uneven and rough surface and when it was torn up you can see where some areas simply did not adhere.

With both coatings the roof had become very thick and even though the two different coatings were bonded very well together the leaks soon continued. In some areas there were soft spots that you could feel with your feet, the bond had separated from the aggregate completely. At first glance it was difficult to determine how these coatings had failed. Perhaps it was the simple fact that it was a walking roof, there were pressures and weight being applied that exceeded the coatings capabilities.

This is a good example why you use trained, experienced, professionals. As you see here the coatings were completly removed down to the aggregate surface. Next step was to smooth out the aggregate so the membrane would have a good suraface to adhere to. Another consideration was the fact that this was to be a walking roof and appearance would be an important consideration as well. A smooth surface would also accomidate a visual change from a roof to a floor. This was important given the amount of traffic the new roof deck garden would be, this will become a focal point.

The sides had been brick with a few scuppers along the length. It looked like the scusppers were anywhere from level to a reverse slope and did little to drain the water off the roof. Again the guys at Upson Company had the right solutions. Remove the exisiting scuppers and fab new ones that would assist in the proper water management. Add three additional floor drains, these would be the primary drainage system and the scuppers would be the secondary. It is a good practice to always have a secondary drainage system as a back up. Here you can also see the walls were covered with plywood during the preperations and would be covered with Duradek

Not quite finished here, some trim will be added to the walls and around the doors but you can see the transformation form roof to floor looks good.

The planter boxes have been made and are sitting downstairs ready to be put into use. I can't wait to see the finished project and get some feedback from the unniversity.