I'm designing an addition onto my existing deck (the existing deck is not pictured below). The addition will be roughly 20' by 15', and I'm planning on making a portion of it a single step lower. While it will butt up against the house, the deck will be self-supporting (I will not be tying into the house for support). The overall profile I'm looking for is this:
My first thought was to frame both levels completely independent of each other, like this:
The obvious issue here being the large number of angled cuts in both deck bands and the complexity of getting beams (not pictured) in proper locations. My second thought was to build both decks as rectangular as possible (the cutout at the left side is for the bay window on my house, so it has to stay) and build a platform on top of the lower portion to create the angular top profile like this:
To make it clear what I did, here is the same design with the new platform moved to the side:
My question is, putting aside local building codes (which both appear to meet, and I'll definitely be getting a permit), is the second design reasonable? Is one better or worse than the other from a structural or safety point of view? Also, not to ask too many questions, but would toe nailing the additional platform to the joists/deck band of the lower platform be sufficient, or should I use brackets to join them together?
Best Answer
The second on is a better choice; in the first one, you have a lot of angles that will make it hard to carry the loads effectively. I would probably go with a 2x6 for the platform on the second deck to get your shape; that will get you 5.5" of difference in height. You could also go with a 2x8 for a 7.5" difference. 2x4 only gets you 2x4, and 3.5" is too short to meet code for a step.
It would be good to see the beams to comment on the overall structure.
Think about lighting for the edge so that you can safely see the step at night.