I'm moving my hot tub to ground level and, after looking for deck
designs, found an interesting one. This was proposed way back in 2000
on one of these newsgroups, but no comments and the poster is no
longer reachable through email. So I thought to re-propose here for
comments.

This design takes into account the weight distribution of a hot tub.
The weight is mainly in the center, in a 4- 5 ft square, and on the
side walls. So using lots of double joists looks like a waste of wood.
How about building a normal square frame, but have only two diagonal
joists. Viewed from above, it would look like an "X" in a box. This
would sit on five 6-inch concrete piers, four corners and one in the
middle, where the diagonals meet. I would then use either 5/4 decking
for the floor, or maybe some PT plywood. The original proposed using
single 2X8's for the joists, but I'm thinking of doubling those.

My other option would be a gravel bed. But my problem is that there's
a slope of about 12" over the 8-ft span. I don't want the gravel bed
sliding down the hill. Might be an interesting slide if I'm in the tub
at the time, but not worth the effort. Digging a level 8X8 X 1+deep
hole, even if it's not that deep at the lower end, might be more work.
And then I still have a 12-inch high gravel mound at the end. So now I
need a retaining wall. The deck looks more attractive by now.

So thanks for any thoughts on this.

-Marc

Well, not quite on target, but... Some years ago, I built a deck.
Because of where it was, needed to be just off the ground maybe 10". I
put 4x4 posts on 4' centers. Then galvanized hangers and 2x8 stringers
to make 2' x 4' grids. Then decked over with 2x6. All treated timber.
Posts were 36" in ground on concrete pads (local code requirement). A
few years later, I put a hot tub on it - pretty decent size - to hold
4-5 people. Held about 350 gallons, IIRC. Deck was maybe 5x the area
of the hot tub. Worked just fine. Clearance under the deck was maybe
4" at one end, and 2" at other end, due to grading. Rabbits loved it.
Would drive my Golden Retriever nuts, as he could hear/smell the
bunnies, but couldn't get to them.