Deck for UNDER my 15' Round Pool

Old 06-28-14, 12:54 PM
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Deck for UNDER my 15' Round Pool

Hello all. The ground in my yard is quite sloped, so digging out for my new above ground pool would be quite the endeavour. Instead I would like to build a 16' square deck to sit my pool on. I would take out the top 4" of sod to clear up any grass issues, and be building on 16" patio stones levelled on a bed of gravel and sand. From there it is a matter of structure to hold the weight of the pool. I was thinking of 12" on centre and using 2x8x16 as my actual deck boards (since 5/4" deck boards have rounded edges). Does this make sense, or is it over engineered and over thought?
Old 06-28-14, 01:32 PM
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I think you'll need a lot more than gravel, sand, and patio stones (I'm not even sure what those are).

You'll need concrete footings and upsized support structure (framing). Assuming you have about a 3300 gallon pool (12 ft x 48in depth) thats going to be around 27,000 lbs or around 240 lbs per sq ft.

I had a 10 ft octagonal deck professionally built for a 400-500 gal spa about 6ft square and it had large footings poured and used 6x6 posts with doubled 2 x 8 joists 12" on center IIRC. This was just 18" or so off the ground.

This isn't something I would do off the cuff.

Seems to me since you'll need to do excavating and concrete work anyway, it might be easier/cheaper to rent a small Bobcat and excavate the soil as needed to level the area.
Old 06-28-14, 01:45 PM
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I agree with Vic. You will need to pour footings to a depth greater than the frost line where you live. Massive footings. Possibly elephant footings. Your support posts would be a minimum of 6x6 set on post bases which are embedded in the concrete footing. You will need a mid span post and beam to help support the 16' lumber. 2x10 minimum for joisting and joist hangers everywhere needed. Post and beams will also need proper fasteners to each other.

Your weight factor alone will be crushing (no pun). Then you need to deal with cross swaying with bracing in all directions.

Do some reading, then consult with your inspection department when you apply for your permit to see what blessings they will give on this. You'll need drawings so work on that, too.
Old 06-28-14, 03:40 PM
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Do I understand correctly that you want to set the pool up on the deck Filled with water that would be a lot of weight, probably too much for any wooden deck.

btw - welcome to the forums!
Old 06-29-14, 10:47 AM
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Actually, the weight of water in a 15'-dia. pool filled to a depth of 4' will be about 44,180 lb. That's based on a unit weight of 62.4 PCF. Which works out to an applied load of close to 255 PSF, or more than 6 times the (live load) weight most decks are designed to resist. Not saying it can't be done, just that the effort and money required for a back yard feature that can't be used much of the year (unless the OP is into ice skating, on a very tiny rink) make it questionable.
Old 06-30-14, 10:50 AM
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Decks need air circulation underneath as well - I don't see anything in your question about height above the ground but I'm not inferring there will be much and that would be problematic.

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