Lisa B
Lisa B
  • Hometalker
  • Snellville, GA
Asked on Mar 22, 2012

Building a deck for a hot tub

KMS WoodworksLisa B
+2

Answered

We are going to build a 10x14 deck to put our new hot tub (delivered in 2-4 weeks) on. It will be on ground that is flat on the front side and will be about 3 feet off the ground in the back. Does anyone know how many 4x4 footings we will need under the hot tub itself (8x8)?
5 answers
  • KMS Woodworks
    on Mar 22, 2012

    This depends a bit on the size of the hot tub? 2 person 6 person etc. My deck design software normally calculates 4 (4") columns under a basic 4 person hot tub with 2 x 8 min joist size. Doubled up joists rest on top of the columns which are set with full depth concrete piers ( 8" sono tubes and simpson AB44 post brackets) In this project (a much smaller deck) ab44 were set in 6" tubes) http://www.hometalk.com/Kevin/project/2602

  • Lisa B
    on Mar 22, 2012

    The hot tub is a 7 person, 7-1/2 x 7-1/2 feet, weighs 4,350 filled then when add weight of 6 people on the deck gotta figure it needs to hold 5,550-6000 pounds.

  • KMS Woodworks
    on Mar 22, 2012

    Ok...that's about 100 pounds per sq foot. Most decks are designed with a "dead load" of 40 psf. I tend to build on the "beefy" side of things so If I were building this I would bump the posts to 6" and sink 4 of them below the tub. For joists I would go with 2 x 10 for the entire project and for under the tub use a "tic tac toe" type of joist grid. With the deck being 3 feet high On one end, this qualifies for "permitting" and should go through your local building regulatory office. Here they may require, an engineers "stamp" for the hot tub part.

  • Lisa B
    on Mar 22, 2012

    Thanks for your input. We like to build beefy too! We were thinking about using 4x4 posts but putting 3 rows of 3 under the tub part and using tic tac toe joist grid. The section of deck (10x4) that the hot tub is NOT over would be built for a load of 40 psf. I hope that will be sufficient.

  • KMS Woodworks
    on Mar 23, 2012

    40psf is pretty standard in the warm parts of the country....at 8500 feet in the rockies a lot of what I built are 60 -70 psf for snow load.

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