Floor Loading for bath tub

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  #1  
Old 11-24-02, 03:24 PM
moe707
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Floor Loading for bath tub

Hello:

I would like to know of how to figure out if my floor joists can take the load of my new bath tub.

The specifications for the tub are: Total weight = 742 lb, 50 lb/sq.ft. The Tub is 60" long x 36" wide x 21 1/4" high. Of course the joists are notched out to run the water pipe and the drain lines.

What sould be the required joist depth and spacing to take the load keep in mind the cut out in the joists for the piping?

Thank you for your info.

Moe
 
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Old 11-24-02, 04:49 PM
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Well, I am no carpenter but I would say that the existing joists are fine... and the notching is supposed to be done in such a way that it does not significantly reduce joist strength... I do have a question though,... what in the world kind of tub do you have that weighs 742 pounds?... Even a cast iron tub will usually only be 300 to 400 pounds... Just curious...
 
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Old 11-25-02, 04:45 AM
moe707
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Tub weight

Ragnar; you are the man.

Sorry, I stated the wrong weight. The tub weighs 92 lbs empty and it takes 48 gallons of water to fill it up. The 742 lb stated in my previous thread is the Total Weight Floor Loading.

I have an old house, so the notches and the holes were drilled for the old tub and now we are installing a new bigger tub and we had to enlarge or make new cut outs at the the top of the joists. The joists are 2x8 with non-uniform spacing.

Thanks
Moe
 
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Old 11-25-02, 11:31 AM
fesjr
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Notching a joist is a no-no. All penetrations thru joist should be drilled in the center third of the joist. When you make a notch, you reduce the overall strenght of the joist. When you have a 2X8 and you notch out 2in on the top or bottom, you now have a 2x6. Check with the local building inspector and they will comfirm this.
 
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Old 11-25-02, 12:49 PM
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I think it would be a big help to know what direction the tub is running. Is it going to lay over the joists, or inline?
If it's laying over them, you might have 4 or 5 joists supporting the weight, if it's inline, there might only be 1 or 2 supporting the weight.

It'd also be helpfull to know how far apart the supports for the joists are. If the tub is going to be sitting on a joist that is sitting on a footer, then the footer will be supporting the weight. On the other hand, if the tub is in the middle of a 12' span...
 
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Old 11-25-02, 06:59 PM
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Well, it sounds like you are talking about a fiberglass tub then, and even full of water you could support it on a couple well place popsicle sticks... They weigh very little compared to the amount of weight that floor is loaded for... Forget the weight rating of the floor, it is MORE than sufficient... Unless you see some OBVIOUS signs of sagging, just dont worry about it... The old tub was heavier than the new, and you will NOT have a problem... As to notching, you generally dont like to take out the "edge" of a joist because it does weaken the joint, but in some cases you have to... just do it and dont get carried away... whenever it is practical, try to BORE through the joist to maintain structural integrity... That will be impossible to do in some areas though, depending on how the waste and overflow is arranged... Just cut as little out as you can get away with, and then sleep well knowing that your flooring requirements weren't designed to just BARELY hold the weight of someone walking on it... They are designed to handle way more strain than what you will ever put on it...

The plumbing code used to give specific limitations on boring... Now it just states that we have to stay structurally sound according to the International Building Code... so feel free to check with a carpenter on specifics if it will make you feel better...
 
 

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