Determine how much weight my deck can hold

April 12, 2004 5:15 PM

I have a deck. I want a jacuzzi out there. Is there a way for me to test how much weight it can hold? Do I need to hire a professional to do that? If so, how much does that cost?
posted by chaz to Home & Garden (8 answers total)

If I'm not mistaken, usually hot tubs are sunken into decks. You cut a big hole in your deck, then pour a concrete foundation on the ground to support the weight of the hot tub, and drop it in.
posted by mathowie at 5:46 PM on April 12, 2004

Not if you're three stories up, Matt.

And for that matter, not on the ground, either. I've yet to see a hottub embedded in concrete. I've been in one California Redwood barrel-style tub: above ground. I've been in innumerable fiberglass tub-style tubs: above ground, all.

Only embedded hottubs I've inhabited were at commercial pools.
posted by five fresh fish at 5:59 PM on April 12, 2004

Mind, you didn't say embedded. All of them did, I'm sure, have a solid foundation.

Except the ones on high decks.
posted by five fresh fish at 6:00 PM on April 12, 2004

I spent a week at a vacation house on the Russian River, and the rickety deck (about 15 feet off the ground) had a pretty large 4-person hot tub jacuzzi on it. On, not in. I've never in my life seen a sunken hot tub, though I know they exist.

But if you want a structural recommendation, hire a structural engineer. They'll run you something in the neighborhood of $100/hour, but won't need much time at all to give you the information you need.
posted by majick at 7:31 PM on April 12, 2004

Call your city's inspections department. They will tell you exactly what the code is for that sort of thing. They'll probably tell you that you have to pull a permit, so I wouldn't give them your name or address unless you want to jump threw those hoops.

You're city's building codes may even be available online.
posted by Juicylicious at 8:57 PM on April 12, 2004

The first thing you need to work out is how much water the jacuzzi will hold (in gallons) and multiply that by 8.345404, which is how many pounds one gallon weighs. Add to this the weight of the tub itself and any filters, pumps etc and you will have a total weight for the whole thing. If you don't already have plans for the deck, draw up a sketch showing the size and spacing of bearers and joists (including the material if you can), the dimensions and materials of the decking itself and the details of how it is held up. An engineer or your local authority should be able to give you some idea as to whether it is capable of holding the weight in addition to the weight of the number of people that could fit onto the deck. As the weight of the tub full of water will have to be calculated in addition to however many people the deck is deemed fit for, it is highly unlikely that the deck can take the extra weight legally, unless it was over-engineered in the first place.

Whatever you do, don't just think that it will be OK as the deck seems pretty strong. Many people have been seriously injured or killed by collapsing decks and you don't want to be one of them.
posted by dg at 9:29 PM on April 12, 2004

I highly suggest hiring a professional to check it out. When we built a deck-expansion onto our house, we also got a fairly large spa. The Spa itself if friggin heavy (to the extent of needing to use a crane to lift it onto a 2nd-story deck). Make the investment now to ensure you have a sturdy deck lest you get screwed later on. Also, deck maitnance is key (waterproofing and that kind of stuff) to prevent the wood from rotting.
posted by jmd82 at 10:26 PM on April 12, 2004

Response by poster: Thanks guys... my ladies really want to start hot tubbin' nightly and I want to indulge them, and myself. So I think I'm going to get a pro out there to spec it out. Thanks for the advice.
posted by chaz at 3:53 PM on April 13, 2004