Rooftop Deck Build


"How'd you build that deck on top?"

This has been one of the most common questions regarding Fern's construction, so here's an explanation of the design and installation:


Our bus body, which I expect is similar to other models, has structural steel ribs beneath the sheet metal of the roof.  These supports are made of 2" square tubing, and like the rafters in a house, they give the roof strength and rigidity.  With 4"x4" posts, the deck is attached directly to these ribs so none of the weight rests on the flimsy sheet metal.  I wanted the deck to "float" over the roof like this so water and debris could easily drain.  Everything was constructed in cedar because the wood has some natural rot-resistance while being significantly lighter than treated lumber.

To begin, I cut a 2"x6" to the length of the deck and mounted it to the center of the roof.  I attached it with self-tapping sheet metal screws to every structural rib.  Using a forstner drill bit, I recessed the screw heads and made sure to seal everything with plenty of silicone.


Next, I cut 4"x4" posts on an angle to match the slope of the roof at the desired height.  The galvanized angle brackets I used to attach the posts to the roof were designed to be used for mounting boat trailer bunks, but they happened to work great for this application too.  I used a 3" lag screw and fender washer to attach to the lumber, and self-tapping sheet metal screws to attach to the roof.  Again, I made sure to apply excessive amounts of silicone.


Once the series of 4"x4" posts were installed (seven on each side), I attached a 2"x4" to run the length of the deck (cut to the same length as the previously installed 2"x6").  I held it to match the height of the posts, and mounted it with 3" deck screws to each of the seven posts.  These 2"x4"s, combined with the center-mounted 2"x6" will provide the support for our deck boards.

From here, it's just like any other deck—throwing down deck boards and screwing them in place!


Once the ladder was installed for easy access, we had space for all kinds of activities!

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