Thread: 6,000 Hot Tub on Balcony

Can a 16'x21' balcony built to meet 60 pound per sq. ft. live load support a 7.5'x8.33' hot tub that weights 6,000 pounds?

Thanks for your comments.
Jack

Originally Posted by Jack Wingo

Can a 16'x21' balcony built to meet 60 pound per sq. ft. live load support a 7.5'x8.33' hot tub that weights 6,000 pounds?

Thanks for your comments.
Jack

No.

7.7x8.33 = 62.475 sq ft.

6000 divided by 62.475 = 96 lbs per sq ft.

Even before you add people, fixtures and movement your over loaded by more than 50 percent.

How did you determine it weighs 6000 pounds?

Originally Posted by Jack Feldmann

How did you determine it weighs 6000 pounds?

Was told by the home owner.

Jack, your intuition was correct. The deck was built as a deck to support people. Hot Tubs need their own support designed separate from the deck design.

Originally Posted by Jim Abram

It is a little more complicated than that. The deck design load is reported as being 60 lb per sq ft = 20,160 lbs.The concentrated load is only 6000 lbs. This is well under the design load.



3.4 Live Loads
For example, the stair
concentrated load of 300 pounds should be applied to the center of the stair tread
between supports. The concentrated wheel load of a vehicle on a garage slab or
floor should be applied to all areas or members subject to a wheel or jack load,
typically using a loaded area of about 20 square inches.

Design deck @ 60 live = 300 concentrated

This says the concentrated load is applied to center of stair tread /20 sq in.
Not 64 sq ft of a structure.( what additional supports are under this load?)

*Home owner info may not be completely accurate.
** not that complicated to me ( Get a Structural Engineer to sign off.)

Originally Posted by Jim Abram

Billy - This has nothing to do with a stair tread. See the chart referenced and posted below.

Jim ,

See reply above.

Bottom line - see below.
We have no technical information as to the structure or the integrity of the connections to the building. Nothing to say it will be OK, plenty to say it will not be OK.
Doing the math to prove otherwise is just irresponsible obfustication, IMO.

Bottom line - a 3-ton hot tub on a balcony which was not specifically designed for that load is a terrible idea, which could have life-threatening consequences.

Originally Posted by Jim Abram

To this day the garage floor supports a large SUV.

Does the SUV invite Dozens of drunken friends over to dance, BBQ and fire off weapons in celebration?

Originally Posted by Jim Abram

John -It is probably more irresponsible to call it life threatening with no information to support that claim .

Could be life threatening. Not irresponsible to say so.

Originally Posted by Billy Stephens

Does the SUV invite Dozens of drunken friends over to dance, BBQ and fire off weapons in celebration?

The party's at your place this weekend?

Originally Posted by John Kogel

The party's at your place this weekend?

You Missed it.
*now ya gotta wait till the Prince & Princess come ta Town.

Originally Posted by Billy Stephens

You Missed it.
*now ya gotta wait till the Prince & Princess come ta Town.

Prince, if he brings a suitable entourage. Otherwise, let me know when the King is back in town.

Originally Posted by John Kogel

let me know when the King is back in town.

Did he go somewhere?

Upstairs at Graceland pictures, Elvis' bedroom, Elvis' bathroom

Originally Posted by Jim Abram

It is a little more complicated than that. The deck design load is reported as being 60 lb per sq ft = 20,160 lbs.The concentrated load is only 6000 lbs. This is well under the design load.
The concentrated load is reported as under 100 lbs/sq ft - The deck design calculation is rated at 300 lbs/sq ft. Just running the numbers it is OK. As far as extra people you have 14,000 design load available.
The bottom line consult an engineer or some one who is qualified to evaluate the deck.

3.4 Live Loads

Live loads are produced by the use and occupancy of a building. Loads
include those from human occupants, furnishings, nonfixed equipment, storage,
and construction and maintenance activities. Table 3.4 provides recommended
design live loads for residential buildings. Example 3.1 in Section 3.10
demonstrates use of those loads and the load combinations specified in Table 3.1,
along with other factors discussed in this section. As required to adequately define
the loading condition, loads are presented in terms of uniform area loads (psf),
concentrated loads (lbs), and uniform line loads (plf). The uniform and
concentrated live loads should not be applied simultaneously in a structural
evaluation. Concentrated loads should be applied to a small area or surface
3-6 Residential Structural Design Guide Chapter 3 – Design Loads for Residential Buildings
consistent with the application and should be located or directed to give the
maximum load effect possible in end-use conditions. For example, the stair
concentrated load of 300 pounds should be applied to the center of the stair tread
between supports. The concentrated wheel load of a vehicle on a garage slab or
floor should be applied to all areas or members subject to a wheel or jack load,
typically using a loaded area of about 20 square inches.

Design deck @ 60 live = 300 concentrated

You cannot look at the total design load for the balcony and compare it to the load on the reduced footprint of the hot tub. To properly calculate the effect on the balcony you would need to know the framing layout and the placement of the hot tub. Without all the information you cannot say it looks ok.

Not knowing how the deck was built and not knowing how the 60#/sf was calculated with a hot tub at 6,000lb at 64 sf surface yields something like a load of 93lb/sf so what is the argument??? The hot tub should be replaced with a SUV?

Originally Posted by Jim Abram

No weapons is the garage as there is a family room above the garage.

Well that Just Sounds Boring!
*Woops your in Yankee Land never Mind.

Originally Posted by Billy Stephens

Does the SUV invite Dozens of drunken friends over to dance, BBQ and fire off weapons in celebration?

I saw a deck today that was way overbuilt, four 8x8 posts on concrete piers, strong enough to support several tons I'm sure. But .... my 167 lbs can get it rocking. There's only one small diagonal support on the one post.
Get 3 tons of water rocking and see what that can do to those posts. They be floppin like a catfish on a pole.

Originally Posted by Jim Abram

. In order to evaluate the balcony ,one needs to be qualified.

Yeah and that don't be us.

Originally Posted by Jim Abram

Mark - As I said -"The bottom line consult an engineer or someone who is qualified to evaluate the deck." Of course ,you cannot make that call on numbers alone but, the balcony passes the design calculation standard.
My point is that it is not an automatic fail or life threatening because it is designed @60lbs/sq ft.
Also , I don't see where it is represented to be a wooden frame. It could be cast in place concrete or precast concrete . In order to evaluate the balcony ,one needs to be qualified.

My point is that you cannot say it passes the design standard because you do not know how the load is supported. Your are attempting to apply standards that you do not fully understand.

Jack,

The attached diagram shows the basic method used to determine if a deck can support any load above the basic 10 psf dead load and 40 psf live load prescribed by code. The hot tub in your photo will have an impact on the section of deck depicted in the diagram. If the added load, in this case the hot tub, was supported on blocks or four legs that would concentrate the load in a very small area, then you would start by checking the deck boards to see if they could carry the concentrated load. Most hot tubs spread the load over the whole bottom area, so you can skip #1.

Start by placing 10 psf dead load over Area 1 & 2 plus 40 psf live load over Area 1 & 2, then add the weight of the hot tub over the foot print of the tub in Area 1. Check the joists under the hot tub, if they pass, check the joist hangers on the tub side of beam AB and beam CD. Next check the design of beams AB & CD. Next check the load capacity of the post connections at A, B, C & D. Finish up by checking the load capacity of posts A, B, C & D, followed by the footing under each post.

The load carrying capacity will be limited to the weakest link in the load path from the deck boards down to the footings.

Sorry Jack, I was responding to a hot tub issued in another message board.

I would need to see a photo, I have never seen a 16' cantilevered balcony on a residential structure. Was it a propped cantilevered or just a tall deck with posts and no stairs?

Was wondering how long it would take to get to the "balcony" vs "deck without stair" discussion would crop up.

Have to love all the assumptions that are being made based on so little information with the added assumption that the info from the OP is correct in every aspect. It may be like the two blind guys on either end of an elephant describing what it is.

Math like the internet never lies and Bees can't fly.

Originally Posted by Garry Sorrells

Was wondering how long it would take to get to the "balcony" vs "deck without stair" discussion would crop up.

Have to love all the assumptions that are being made based on so little information with the added assumption that the info from the OP is correct in every aspect. It may be like the two blind guys on either end of an elephant describing what it is.

Math like the internet never lies and Bees can't fly.

The word balcony gets used in different ways. A true balcony from a code standpoint would cantilever from the structure. I don't recall ever seeing a balcony cantilever 16 feet. So we are all left to guess the information that the OP left out.

Originally Posted by Jack Wingo

Can a 16'x21' balcony built to meet 60 pound per sq. ft. live load support a 7.5'x8.33' hot tub that weights 6,000 pounds?

Thanks for your comments.
Jack

Originally Posted by Jack Abram

My point is that it is not an automatic fail or life threatening because it is designed @60lbs/sq ft.

Well apparently it is an Automatic Fail.
*attachment states if area is over 100 sq. ft minimum is 100 psf. live load.

Originally Posted by Jack Wingo

Can a 16'x21' balcony built to meet 60 pound per sq. ft. live load support a 7.5'x8.33' hot tub that weights 6,000 pounds?

Jack, do you have pictures from the balcony deck and one looking up to see the supporting framing, or can you easily get them? This is essential, as you can see, in answering your question. Also, is the balcony first or second floor? Are there any supports under the balcony? Pictures of this would also be helpful.

Originally Posted by Jack Wingo

Can a 16'x21' balcony built to meet 60 pound per sq. ft. live load support a 7.5'x8.33' hot tub that weights 6,000 pounds?

Thanks for your comments.
Jack

Lots of commentary for a simple answer. As a generalist, you need to know when to call for an evaluation by a structural engineer. As a HI, you can overstep your expertise and role by trying to factor all the variables and math on this.

Tub parties with guns..........what can go wrong? Count me in...........as long as an engineer has deemed the balcony deck safe to hold the load cause I am Mr. Safety.

Originally Posted by Billy Stephens

[COLOR=#3E3E3E]

Well apparently it is an Automatic Fail.
*attachment states if area is over 100 sq. ft minimum is 100 psf. live load.

The live load you stated is correct, assuming this is a balcony, which it is probably not.

Originally Posted by Mark Reinmiller

The live load you stated is correct, assuming this is a balcony, which it is probably not.

Well thanks Mark.
*it's why I read the link before posting it.

Jim,
Need to add in the 8 linebackers and 4 cases of beer and maybe a few Cheer Leaders and some other friends. Oh, don't forget the music and dancing.

Originally Posted by Jack Wingo

Can a 16'x21' balcony built to meet 60 pound per sq. ft. live load

Thanks for your comments.
Jack

Originally Posted by Jim Abram

Billy - If the design is 100 psf and the hot tub weighs 96 psf ,it passes.

Jim,
OP stated the ( contested balcony / deck ) was rated @60psf. not 100 psf.
*the attachment says if the balcony is over 100 sf them must be rated 100pst. so automatic fail based on our limited information.

Mark Reinmiller could give us a definite answer if he were provided the actual information.

We as in you/I could not.
*your stack barrel looks like a 1960's Hardware Company Brand gun someone unqualified put a recoil pad on.

Any deck with a hot tub should be specifically designed to carry that heavy of a load under the tub itself. I would recommend a structural engineer take a look at it and make a recommendation as to how to reinforce the deck to hold the weight otherwise the tub should be moved elsewhere.

Even an under constructed deck may hold the tub just fine but then again it may not. Water is about 10 pounds per gallon plus the weight of the tub, a previous job of mine was working in the aquarium industry and I have seen very heavy aquariums held up by floor joist that should never have held them but ive also seen catastrophes where they fell through the floor. Always better safe than sorry, fix the deck.

Gallon - Wikipedia, the free encyclopedia

Originally Posted by Jack Wingo

Can a 16'x21' balcony built to meet 60 pound per sq. ft. live load support a 7.5'x8.33' hot tub that weights 6,000 pounds?

Thanks for your comments.
Jack

Typical 4-5 person hot tubs are around 500 gallons and in another 250 lbs for the weight of the unit and you have right at 6,000 lbs. Water weighs around 8lbs per gallon.

Add in the weight 4 adults will push it up another 600 to 800 lbs or better!

I have seen many hot tubs on decks of cabins in the Smokies and I wonder every time with some I see why they have not collapsed the deck.