I’m probably way off on the distance there, I would bet that with 2” x 8”s they won’t be 20’ long and that perhaps another beam is in order, even with a 48” cantilever over the beam that would have about 16’ span to the house and that would be a bit too long of a span, it would be rather ‘splashy’ in terms of spring and rebound. This isn’t even counting what the plans are for the footings and support columns, and what height it is off the ground. Is it low enough that guardrails are not required or is it high enough that they will be? If it is elevated then there will be specific considerations for the support columns in terms of the depth of the hole. And I’m not even a carpenter, though I am a plumber so I do have to deal with framing by knowing what can and what cannot be court out of my way
