Deck strength

[GoWyoGo]

Still trying to decide where to locate my tub when i get one. I can't very easily re-do the cracked cocrete pad as winter has set in and i need to move sprinklers, etc. I am now contemplating setting it on our deck, but have no idea whether it is strong enough. My last deck was built like a brick s*@! house but since i didn't build the one at our new house, i am clueless about determining the strength. Does anyone know how to calculate the PSI a deck can support, or just determine if it will support a spa?

Love this board. don't post much but do enjoy all the contributions from others.

[Jacuzzi Jim]

 Some codes I suppose could vary,but I think a rule of thumb is 100 to 150lbs per sq ft.

  Best to if there is a question get a deck guy or contractor to look at it.

[GoWyoGo]

Jim are you saying that is code to support a tub, or just code for a deck to be built properly regardless of what is resting on it? thx for the quick reply

[Brewman]

Does your city or county have a building department that can help?  
 They might have code requirements on deck load minimums for spas, and might be able to help you determine if your deck is built to support that load.

[hottubdan]

I think it would depend on the spa and how the weight is distributed.  From what I know, a deck built to code will support many spas, but perhaps not all.

[Jacuzzi Jim]

Jim are you saying that is code to support a tub, or just code for a deck to be built properly regardless of what is resting on it? thx for the quick reply

 Applies to general deck building, best to check with the locals in matters like this.
Alot depends if you are pulling a permit,are you building the deck yourself so on and so on.  If a company is doing it for you they will most likely pull there own permit and they will build accordingly. Same with electritians.

[Zep]

is dropping it in the deck an option?

have it semi-in-ground or semi recessed in
deck and then deck support is mute?

[Vinny]

Here's my $0.02.

If you don't know how strong the deck is DON"T assume it will hold a tub.

At 8 lbs/ gallon water can get very heavy, depending on where you live you need to add snow loads and don't forget about possible wind pushing on the tub. Add people and you're talking tons.

Here's some simple calcs:

   Tub                      =     800 lbs
   400 gallons           =    3600 lbs
   Deck stuckture      =      500 lbs  (this may be more or less - I'm thinking less)
   4 people at 200 lbs =     800 lbs

Total = 5700 lbs - close to 3 tons sitting on about 64 sq ft.

Decks can be reinforced to hold the weight - I agree that you should check with your town, their the best place to start.

[bosco0633]

vinny, my image of you continues!!!

[Vinny]

vinny, my image of you continues!!!

What did I do now?  

Although I don't think I dress like a nerd or possibly look like a nerd, deep inside I am a nerd. I have to say I like to learn things and research things till my head explodes (that may explain things). It drives me nuts when my kids don't go the extra distance when they really want things. My oldest recently took his driving permit test and barely passed yet he wanted it his permit BADLY - I asked him how come he didn't ace it and his comment was what's the big deal; for me I would be upset if I got 1 wrong.

My brain has a wealth of information (a lot of times useless). You got to see what it's like when I do projects around my house ... it takes forever because my brain and hands don't communicate well. I poured a concrete pad for my steps for the deck, I must have measured about 5 or 6 times. In my mind it looked good, was sure it was big enough, blah, blah, blah ... the steps barely fit and they actually hang off the pad a little and the room in front is smaller than anticipated. This only one story ...

The info is correct, but the execution is very lacking.

[hottub.pool_boy]

These are general parameters we use:
    deck needs to be lag bolted to the sill/ foundation etc, if it is not. Re-inforcement of an existing deck needs to be where the spa is to be located. Doubling up the floor joists where the spa will be is a good idea. You need a carrying beam under the spa, 8ft in length, triple 2x8 or 2x10. to two posts. The posts should be 6x6's one ft in from the edge of the beam. to concrete sonotubes/footings to virgin soil.
In the area of the spa, no span between carrying beams should be greater than 8ft or so.

[patty]

Vinny, are you by chance a leftie?  you just described me    

[Vinny]

Vinny, are you by chance a leftie?  you just described me    

Nah, I'm a rightie!

[GoWyoGo]

Thanks again...I have decided not to drop onto deck, as i'm fairly sure it would be lucky not to buckle. I am going to set inside the deck, but curious as to what people who do this do when service is required. If it is surrounded by decking an all four sides instead of 3, how do you "open her up" if/when service is needed? does it require some deck disassembly? just curious.

you guy/girls are great!

[Brewman]

From what I've heard and seen, people who sink spas into their decks build the deck so the boards surrounding the spa can be removed for service access.