I would like to add 10X10 deck, 3 feet off the ground, adjacent to my existing 15x15 deck (making sort of a "L" shape) to hold an 8x8 hot tub. The existing deck is 4 years old but was not intended for a spa and there will be no more room to sit on it if I put the spa there. I would prefer to use a concrete slab, but that is not an option.

I live in Minnesota so I plan to set 4 - 4x6 posts in 48" footings. The posts would be centered under the hot tub in a 5 foot square.

I would connect 3 - 2x6x10 boards to create 2 beams and then use 2x6 joists at 16" centers to span the beams. Normal treated decking would create the floor.

Is this plan accurate? Are 4 footings enough?

Thank you in advance for any help you can provide.

 

A 10' X 10' deck for an 8' X8' only leaves you a foot of deck exposed on the 4 sides of the tub. Not enough in my opinion. Also, with only 4 posts, and a 5' span between the posts, that leaves you a 30" cantilever -- that is at least 6" too much. DON'T set the posts in the concrete -- THEY WILL ROT! Use an embedded post base such as a Simpson CBSQ46 or EPB46 in the concrete and attach the post in that.

More posts are needed, and, in my opinion, so is a larger deck. I would make the deck at least 12' X 12', leaving at least 2' on each side of the tub exposed, Use 9 posts, spaced 5' apart. This leaves about a 12" cantilever. Use 4X6's for both the posts and the beams. Use something like a Simpson AC6 to tie the posts to the beams.

Around a hot tub, I would use Trex or some other composite for the decking. It is impervious to the water that is going to get splashed on it.

 

I am intending this as more of a platform to hold the tub than a deck. I have a very nice deck already, I just want the tub next to it. I would consider an 8x8 deck (platform) to set the 8x8 tub on so you would not see anyextended decking. There is no need for anyone to walk around the tub.

Does that change your advice?

 

Either make the deck flush with the edge of the tub, or leave a 2' walkway around it. Leaving just a 1' bit of decking exposed around the tub would be a mistake, ESPECIALLY if there is a 3' drop off of the edge. If you go with the 2' of exposed decking, put a handrail around it, and I would suggest making the exposed decking 3' wide. Making the deck flush with the edge of the tub would, in my opinion, also be a mistake. If the botom of the tub is 3" above grade, the rim of the tub is almost 6' above grade. THAT is one long step!! No, I would leave AT LEAST 2' of deck exposed around the tub.

And I would not embed the wood in the concrete. I would put it in post bases to eliminate the rot problem.

 

Best laid plans ...... Due to an inaccurate marking by the telephone company, my whole plan is out the window. 3 ft into one of my footings, I hit the phone line. Did not break it but obvioulsy I cannot continue on that mark. That is the only spot to put a footing too.

Plan "B" - scrap the deck/platform idea and extend the retaining wall in order to place the spa on top of the area enclosed by the brick.

Wall would be no more than 3 ft high.

Can you point me in the right direction for discussion on this? I am probably going to contract this out, but extra knowledge is always beneficial.