Deck strong enough for spa?


  #1  
Old 07-20-05, 03:50 AM
cdysthe
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Deck strong enough for spa?

Hi,

I have a spa I would like to place on my deck. How do I determine if the deck currently is trong enough, or if I need to reinforce it? I have been looking around the web, but the information I find is kind of confusing and contradictory. I may need to consult a contractor, but if there are ways I can determine this myself it would be great. If someone has advice and/or pointers regarding spas and deck strenght it would be greatly appreciated.

//Christian
 
  #2  
Old 07-25-05, 06:56 AM
S
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most portable spas hold 250 plus gal of water that figures over 2000 lb.

a lot of weight , suggest you get a building tradsman in there to evaluate.


lol steve
 
  #3  
Old 08-15-05, 11:22 AM
E
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We asked the same thing when we got our spa. We were told that generally, decks are not built with enough supports to manage that much weight. Every contractor suggested tearing up and rebuilding the deck. Instead, we ended up pouring a concrete slab alongside the deck. It's also easier to remove the panel for servicing, too.
 
  #4  
Old 08-17-05, 10:47 AM
W
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You might try your local building inspector for guidelines in this area. Mine helped me when I faced this same question. You need to have the weight of the spa. You need to have the deck structure info, how high, joist information ....how many inches on center, joist span, and joist size ...2x8, 2x10 etc. With this info a knowledgeable builder or inspector should be able to give you some good info.

There are things you can do to add more support, such as doubling or adding more joists, which in many decks can be done fairly easy. When I did this on my ground level deck I decided to add more joists, and also poured two more footings for an additional beam under the joists, all under the space for the hot tub. In our climate that meant partial deck disassembly and digging 4 foot deep footing holes in the ground between the existing joists, pouring concrete, adding the beam, and then adding extra joists, and reassembling the deck boards removed. It was a long weekend project, with low material cost. Depending on your climate (frost line), deck height & structure, this can be an easy or difficult task. In rocky soil in northern climates, using one or 2-man post hole diggers are a hard job, almost dislocating your shoulders when they hit rocks.
 
  #5  
Old 08-26-05, 04:45 AM
S
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Here are some "worst case" numbers that help to show that a typical deck isn't up to a spa's weight:

500 gallons of water at 8.3 pounds per gallon is 4150 pounds.

A late-model Cal Spa is about 8 foot square, and about 1400 pounds. Yes, they are getting quite heavy with the built-in TV, multiple pumps and such.

4150 plus 1400 pounds is 5650 pounds, divided by 64 square feet, that's 88 pounds per square foot.

Interior rooms are typically 30 pounds/square foot design load, bedrooms are typically 40 pounds/square foot design load, and a typical roof will most likely be designed at less than 50 pounds/square foot design load. A deck builder might know by heart what is needed to support a spa, but your typical carpenter won't.

Actually, the Southern Yellow Pine website has "span tables" for such heavy loading, and the APA (plywood association) website deals with heavy design load floors such as garages. No guesswork is needed, just follow the span tables. The APA site is not really needed in this situation, since the load is spread out by the spa's frame.

I am not saying you should do it yourself. You should patronize one of the fine contractors advertising on this site. But, you SHOULD know what to expect in materials selection and materials costing, and that's where those sites come in handy.
 
 

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