A ballasted solar PV mount is a graceful, highly engineered solution that secures the array without damaging the flat roof. It is compatible with the usual framed photovoltaic modules and typically does not require roof penetrations. Made from lightweight and strong aluminum construction, this Uni-rack Rapid Rack G-10 system is at a 10-degree tilt and will look pretty sweet when it’s done.
Photos show the team setting up the base of the system, which includes the ballast block trays which each have a 4″x8″x16″, 26-pound cement block in each tray. There are 5.5 blocks per panel, to keep it properly weighted down.
In these photos you can see the 30# strips of 36″ wide tar paper below the blocks, trays, and ballast frames. You’ll notice that there are rocks on the roof. This is to protect the EDPM membrane.
We needed to replace the building paper with Colbond Enkadrain mat that allows the roof to drain under the entire racking system. Roofer Stan Howard specked this product, and this is the proper way to do any ballasted system. In the picture, the guys are using a table saw to cut this stuff – funny – sometimes you need to pull a MacGyver move on the job.
In this scenario we made sure to request information from UNI-Rac on how to attach the Enphase M-215 microinverters to the Unirac G10 rapidrac ballasted racking and attached them as specified to the brackets. From now on we will use WEEBs to bond the Enphase microinverters to our racking saving a lot of 6 gauge copper bonding wire.
Overall our team liked the rapidrac system and it went together surprisingly quickly. Hopefully we will have a chance to install it on a future job before the river rock ballast is put down. Learning Moment: having to manage existing rock is a large portion of the job.
This system is (4) separate arrays of 9 modules combined on the roof producing up to 8.4 amps at 240 volts AC each for a total of 8.1 kW AC. The system size is 8.64 kw – (36) 240 watt modules. The owner will need to install his internet service before we are able to monitor the system online. The system has already passed inspection and the Net Meter Agreement is signed and in the line up for having it installed. It should be activated when the net meter is installed so they can use the electricity produced from the array while they are finishing construction on the home. Back to More Projects