Looking for some advice. We are building a small deck in Westchester County, NY, it will be 8′ x 13′, plus the stairs that are along the 13′ length, down to grade. The stairs have 5 treads. The architects original plan showed four stringers hitting four sonotubes that are 42″ deep with flared bottoms – so I (stupidly) assumed that we only needed 4 of them across the 13′. Now that I’m looking at it with my contractor I see that we need at least fourteen stringers 16 o/c, and probably more becuase we’re using Timbertech. For the footings, since the sonotubes have 24″ flared bottoms we can’t fit more than 6 side by side anyway.
So, I’m pretty confused about what the heels of all those stringers will sit on. Should we plan on pouring the sonotubes to grade and laying a sleeper over the finished height of the tubes? I think that would work but we would prefer to lay the patio down and have the heels of the stringers sit on the pavers instead. What type of assembly should we use to do that? Thanks in advance!
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I would seek clarity from the architect who designed this. The last deck I built had a 4 foot wide stair and was to commercial code standards. My engineer specified a continuous footing across the five stringers with a rebar grid.T/he top was 52"x 18" and it was 30" deep (many bags of concrete, around 38 80#).
thank you mikeljon. i’ve asked the inspectors office and hoping to hear from them. also asking an engineer friend what they think. seems like 42” deep is just nuts.
Looks like code for frost depth in your area is 42" (I'm in MD and it's 30").