How to reinforce my deck for a hotub??

[850-R]

I am planning on getting either the Sundance optima or the Marquis euphoria very soon.  I was wondering what you would recommend as bracing for the deck.  It is 9.5 feet off the ground and has a 4-6 inch thick concrete slab under it.  I use the area under the deck to park my mower so I would like to still be able to do that if at all possible...

Thanks

[HotTubMan]

Consult a proffesional, but here i the advice I give shoppers:

If your posts are 10' or closer and your joists are 2*6, 12" apart or closer, you are good to go.

HTM

[Vinny]

It depends on how the deck was originally built.

My dealer said to build a deck for 150 PSF load, it consisted of a 3 - 2x10 beam every 6 feet going to a 6x6 in 12 inch footings, I believe they said use 2x8 joists. I don't know the on center dimensions for the joists (I guess assume 12 inch oc). The other consideration is the height of the deck, usually the higher the deck, the more structure is needed to support the weight. A deck 3 feet off the ground needs smaller posts and beams than a deck that's as high as yours.

The other thing to consider is the decking it's going to sit on. Some of the composite wood is rated to 100PSF, Timbertech tongue and grove planking has ridges that it sits on and may in my opinion crush under the weight of the tub because of very little surface area actually sitting on the joist.

Some townships may require a structural engineer to certify the deck can handle the weight.

Hope this helps!

[Brewman]

Your city, or whoever enforces building codes in your area may be able to help.  Full, the Optima comes in at just under 5000 pounds.
Your decks load bearing potential depends on a lot a variables- Joist size and spacing, beam support, footings, etc....
Our city engineers assist homeowners with things like this, perhaps yours would also.
Brewman

[empolgation]

Your getting good advice thus far... there's more than one way to do it right and many more ways to do it wrong. Considering that you need to ask the question means that you should consult your local codes and a structual engineer.

[Chas]

That 9.5' off the ground is what scares me. Here in CA you would want one of two things: earthquake bracing, or an ejection seat built into the spa.

But if your deck is built using standard construction: 16" or less on center for joists, one inch per foot or better for beams (2x4 spans 4 feet or less, 2x6 six feet or less, etc) then you should be fine with one addition. You should add a strongback under the center of the spa. This can be done in many ways. If you can simply double up one or two joists which run right down the center of the tub (put a 2x of the same size next to an existing joist) or run a 4x across the joists if that's the way the center of the tub runs. This strongback should have one, two or three posts of it's own, or one of it's own and bolt to two exising ones.

Did any of that make sense? It's late and I had a long day...