Calculating dead load for partition wall with bath


Old 10-18-05, 12:25 PM
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Calculating dead load for partition wall with bath

I am considering placing a partition wall on the second floor of a 2 story balloon construction home. Home was built around 1910 and is all yellow pine. Floor joists are 2x8, 12'6" span, 16"OC, and parallel to the proposed wall (not perpendicular). I need to maintan l/360 if I want to tile the floor in what would become the bathroom. I'm pretty sure my idea isn't going to fly without a supporting column, but hope I can get by with doubling all joists in the area and also adding joists to make it 8" OC instead of 16"OC.

Originally I was going to ask how to calculate the dead load for the joists under a wall, but after much investigation while gathering the relevant facts I am instead asking...

#1 What is the standard live and dead loads assumed under a partition wall in a residence?
#2 What is the standard live and dead loads assumed under a 30x60 tub? 414 lbs water fill weight?
#3 Is 40/20 really what I should use, or should I go to 50/20 or something else?
#4 Should I just get rid of my dream of upstairs tub parallel to joists on a 12'6" span and instead stick with a shower?

Any information is greatly appreciated even if you don't care to answer the questions posted. BTW, no building permit because unincorparted area and county does not require, nor willing to offer direction on such renovations.

Thank you

Last edited by getitdone; 10-18-05 at 09:35 PM. Reason: Clarify tub relation to joists
Old 10-18-05, 01:08 PM
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My current proposal

My current proposal is based on the AWC joist span calculator and is as follows. ("")

Species: Souther Pine
Size/Grade: 2x8, No. 1
Deflection: L/360
Spacing: 12" OC
Live Load: 50
Dead Load: 20

The calculator says this is capable of spanning 13'5", so that is a full 12" longer than my span. If I double all joists with the Souther Pine and all additional joists to bring it close to 8" OC I think I should be safe. All assuming that a 50/20 load is correct.

Anyone see any problems with the above idea? Thanks.
Old 10-18-05, 08:08 PM
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Location: santa Rosa, California
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even with the numbers you gave southern pine #1 only has a modulus of elasticity of 1,500,000. On 16" o.c. it can span a max. 12'-7". Here we have to allow one foot under the max span as an assumed allowable span to eliminate bounce which you definately do not want with tile. Code and standards only ask that we provide dbl. joists under parrellel conditions. If it was my floor I would do exactly what you have said. I would dbl all my joists and solid block the midspan. The floor assembly should not have any bounce and you have more than enough support for the tub and all your loads. the code tables give you 40 lbs live load per sf assumed and 10 lbs dead load per s.f. so if you are concerned you can allways beef up under tub for a little peace of mind.
I hope this helps.

Brian Garrison

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