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-   -   existing deck load? (http://www.diychatroom.com/f19/existing-deck-load-156033/)

ajum 09-06-2012 01:51 PM

existing deck load?
 
hello,

we would like to know if our existing deck can handle a med size hot tub. The finish deck load = 200 psf. here's the basic existing deck data:
- 4 concrete footings to frost with 10" concrete tubes at grade.
- pt 6x6 posts, 2' high.
- posts form a 10' square.
- double pt 2x10 beams parallel on two sides.
- single 16" oc pt 2x10 joists on top of beams.
- pt 5/4x6" decking on top.
- one end is eventually anchored to house ledger (just fyi).

that's all i can think of that matters. basically, a 10' square deck made of 2x10 beams/joists, sitting on 6x6 corner posts, on concrete piers. the 7'x7' hot tub will go on this square somewhere +/-inches.
can this deck handle a 200 psf load???

we can't get under deck to dig, but we may be able to add more/double up 2x10 joists or triple up 2x10 beams... but only if necessary.

thanks!

GBrackins 09-06-2012 01:55 PM

a few photos would aid in getting useful answer .....

how about a concrete patio next to the deck for the hot tub? don't have to worry about the hot tub then

GBrackins 09-06-2012 02:42 PM

where did the 200 psf load come from? what is the weight of the tub, # of occupants, and water capacity in gallons?

OKDrew63 09-06-2012 02:49 PM

I would think a tub that size would be close to 5K pounds, with water and occupants. At least our 7.5'x7.5' tub (that we are buying) is close to that.

TheCamper 09-06-2012 09:36 PM

I don't have the reference books available at the moment, but my gut feeling is you are not close to 200 pounds per sq. ft. You are transferring the weight to four piers that together are a bit more than 2 sq. ft., Although I do not know your soil conditions this is marginal in most soils for the proposed load. 2 X 10 Pressure Treated joists (southern yellow pine?) 16" o.c. on a ten foot span are not likely to give you 200 pounds per sq. ft., probably half that. You would benefit from a professional engineer reviewing the design and specifying additional support, if necessary. Search for span tables for joists and girders such as http://www.southernpine.com/span-tab...?redirect=true or http://www.awc.org/calculators/span/...rcalcstyle.asp to get an idea of the load your deck might support and then figure the load the piers can take; search soil bearing capacity. If the deck is only a few feet above grade perhaps you may want to cut the deck, pour a concrete slab and have a "sunken hot tub". The tub would be supported independently of the deck.
good luck and enjoy the tub.

hand drive 09-06-2012 10:01 PM

how does the deck attach to the house or is it a freestanding deck?


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