How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask StructuralEng Your Own Question

StructuralEng
StructuralEng, Consultant
Category: Structural Engineering
Satisfied Customers: 4536
Experience:  Structural Engineer
Type Your Structural Engineering Question Here...
StructuralEng is online now
A new question is answered every 9 seconds

pine 2x10 floor joists...I think 16 on center...how much weight

Customer Question

pine 2x10 floor joists...I think 16 on center...how much weight can they support? Does it matter if 1st or second floor? E.g. I want to put a larger soaking tub in the master bath. Do I need to be concerned? Also, I've had 20 or more people in my kitchen & eating area before during a party. Is that dangerous? That's like driving my suburban into my kitchen, surprised it hasn't caved in the house.
Submitted: 2 years ago.
Category: Structural Engineering
Expert:  StructuralEng replied 2 years ago.

StructuralEng : Hi
StructuralEng : I can help you with this. Give me a few minutes to read the question complety
Customer:

I really need more of a common mans answer, not a technical load mathematics answer

Customer:

so give me enough details to be comfortable but please don't make me do the math :)

StructuralEng : No problem.
StructuralEng : What is the length of the joists?
StructuralEng : Do you know I'd they're southern pine? Do you know the grade?
StructuralEng : If, not I'd.
Customer:

hmmm

Customer:

well, they're roughly 13 feet

StructuralEng : And where along the 13' span do you want to put the rub?
Customer:

scissor truss design, 2 story colonial,

Customer:

vaulted ceilings and such

StructuralEng : How far from the end?
Customer:

near the middle of the house

StructuralEng : Will the tub be oriented so the long dimension is perpendicular to the joists?
Customer:

so the house is split into two 13 foot halves essentially

Customer:

probably, but not necessarily

StructuralEng : Near the middle of the house is at the end of the joist span, correct? Near a bearing wall?
Customer:

the tub might be same length and depth

Customer:

larger soaking tub type thing

Customer:

yes, near the center load bearing wall

StructuralEng : I hope you done have 2x10's spanning 26' or else you have a much bigger problem on your hands.
Customer:

no, definitely pretty close together

Customer:

not 26' for sure

Customer:

oh

Customer:

you mean span

Customer:

sorry, no I've been in there

Customer:

I know they're split into two that overlap at the center load wall

Customer:

each side has it's own independent 13' span floor joists

Customer:

actually

Customer:

on the other side of the house there are no joists

StructuralEng : Ok. If they're going 13', then your 2x10's @ 16" o.c are fine for the tub, provided its near the end.
Customer:

open foyer

Customer:

there's already a tub there

Customer:

so it would be just replacing it with larger one

Customer:

and it is already near the load wall

Customer:

what about the 20 people in my kitchen?

Customer:

is that dangerous?

Customer:

because how can people have parties??

Customer:

if I do the math, that's literally like driving my suburban into the kitchen

StructuralEng : Also, I wouldn't worry about too many people in your kitchen or living room. Residential construction is typically 40 psf LL. if you have a 15' x 10' kitchen, that's 150*40 = 6000 pounds (evenly distributed, of course). That's easily 30 people who weigh 200 pounds each. Unlikely to happen in such a small space.
Customer:

close to 1.5 tons

Customer:

So, assuming the weight were distributed evenly, it actually would hold the suburban

StructuralEng : The difference between the truck and the people is that the people are spreading the load over a large area to all of te joists. A truck would load only 4 joists very heavily.
Customer:

funny

Customer:

so....how large a tub can I fit upstairs then?

Customer:

how heavy

Customer:

in terms of water volume weight

Customer:

and of course, there's a person in the tub, so add 200

Customer:

what you're telling me is....if I do the math

Customer:

40psf

StructuralEng : If its at the end of the span, and te long dimension of the tub is perpendicular to the joists, you can go up to 3'-6" wide. The end of that 3'-6" shouldn't extend any further than 4'-6" into the span of the joist.
Customer:

so if the tub is 5 x 4, e.g

Customer:

20 sf x 40psf = 800lbs

Customer:

why does joist position matter?

StructuralEng : The full tub will be higher than 40 psf. The reason it's ok is that it's at the end of the span (not contributing as much to bending, more to shear). Additionally, 2x10 pine joists spanning 13' is pretty robust for residential construction. I would typically see 2x8's spanning that length.
Customer:

definitely 2x10 and definitely 16 oc

Customer:

maybe less actually

Customer:

I can't remember exactly

Customer:

but I had the ceiling torn open at one point and they are definitely really close together

Customer:

I ran a few wires

Customer:

could barely fit my cordless drill between them

StructuralEng : If you've found my answer helpful, please "accept" it. I'll be happy to answer additional questions on the topic. If you could provide feedback, I would appreciate it.
Customer:

well, yes, I have

Customer:

thank you very much

StructuralEng, Consultant
Satisfied Customers: 4536
Experience: Structural Engineer
StructuralEng and other Structural Engineering Specialists are ready to help you
Customer: replied 2 years ago.
One thing I did not mention, which I think may be very important. On the second floor, above the load bearing wall, on the same side as the existing tub, is a hallway. Again, valuted ceilings, open foyer, so front half of house is all open, nothing resting on this section of the load wall, but back half has about a 3.5 foot wide upstairs hallway, behind which is the existing tub, so in reality, the tub is already more than 4 feet away from the load wall. Is this dangerous given the 16" on center 2x10 joists? ( I verified, definitely 16" on center). Again, scissor trusses, so no truss load on the hallway wall as I understand it.
Expert:  StructuralEng replied 2 years ago.
It won't cause the floor to cave in, but could definitely result in excessive deflections and cracked finishes. I would add new joists between the existing for the extent of the tub.
Customer: replied 2 years ago.
What does that mean? I an add joists?? Between 16 on center joists? Is that even possible? What about all the wiring that's already in there? Is that even possible?
Expert:  StructuralEng replied 2 years ago.

I have another option, but it will require some work. Either way is going to be a fair amount of work to get the numbers to check out on paper.

 

To add the joists, you'll have to cut the wires, pull them back and then add a junction box to reconnect everything. I know it's a pain, but we've had to do this before in residential applications.

 

Another option is to sister the existing joists with metal studs. This will make working around the existing wiring and plumbing much easier, but requires more engineering and detailing on my end. I can do this for an additional 40, if you're interested. Just let me know.

Customer: replied 2 years ago.
what do you mean an addtional 40?
Expert:  StructuralEng replied 2 years ago.
I mean I'll do the analysis and sketches for a fix for a bonus of 40. This would be above the fee already paid.
Customer: replied 2 years ago.
Is there any alternative, like for example load sharing between the first and second floor with another wall right under the upstairs wall that then spreads the load between the first floor joists and the second floor joists? Or does it not work that way?
Expert:  StructuralEng replied 2 years ago.
There could be, if that wall that's not at the end is load bearing, but I don't believe it is. If it were, then the joists below would not work, because they can't take the load of both floors.
Customer: replied 2 years ago.
interesting...so my house was constructed poorly, inspected along the way, and now I've got to remedy the poor construction. GREAT! So if I go ahead with the plans, how much would you expect I'm in for in terms of implementing the whole remedy? Given that they're 16 on center, I would suspect that the I need to do this for the length of the wall upstairs, which is about 22 feet long...really? Wow! Below that entire 22 feet is my kitchen, which has soffets for plumbing from the bathrooms above it. So, I would have to have someone come in and sister about 17 joists, which would include working around soffeting. Really?
Expert:  StructuralEng replied 2 years ago.
No, the issue only exists where you want to put this heavier tub. You would only have to do it for the 5' extent of the tub, but the sisters will need to be full length. It's fine for typical loading, just not for a tub loading at that particular location.
Customer: replied 2 years ago.
So the hallway wall upstairs that is 3.5 feet from the end of the joists (scissor trusses remember) is fine then. Ok. So...when you talk about metal sisters for these 4 or 5 joists then I'm picturing something like the 9th picture from the bottom on this site: http://hall-house.blogspot.com/
Expert:  StructuralEng replied 2 years ago.
I can't view that site right now. Will respond ASAP.
Customer: replied 2 years ago.
Ok, I also see this kind of synthetic material sistering out there, but seems like your idea of metal is the best because I can hopefully go around all the wiring up there. Also, if there were some piping that were in the way of the 5th joist for example, toward the end of the tub...would it be ok to just leave that one unsistered? In other words if I get the majority of the joists under the proposed tub sistered, is that "good enough"
Expert:  StructuralEng replied 2 years ago.
Yes, it will be ok for the last one.
Customer: replied 2 years ago.
if they were actually closer together where the tub is when I open up the ceiling...would that make a difference? Say they're 14 or 12 on center there. Could that support the tub at 4 foot from the load wall?
Expert:  StructuralEng replied 2 years ago.
12", maybe depending on species and grade. 14", definitely not
Customer: replied 2 years ago.
and on the cost to implement something like this? What (roughly, will not hold you to anything) am I looking at?
Expert:  StructuralEng replied 2 years ago.

A couple hundred buck, tops........... if you do it yourself.

 

For a contractor - a few thousand.

JustAnswer in the News:

 
 
 
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
 
 
 

What Customers are Saying:

 
 
 
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
< Last | Next >
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY
  • Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know. Robin Elkton, Maryland
  • He answered my question promptly and gave me accurate, detailed information. If all of your experts are half as good, you have a great thing going here. Diane Dallas, TX
 
 
 

Meet The Experts:

 
 
 
  • walkereng's Avatar

    walkereng

    Consultant

    Satisfied Customers:

    1396
    Over 28 years of Structural Engineering experience.
< Last | Next >
  • http://ww2.justanswer.com/uploads/WA/walkereng/2012-2-2_4226_Brad2.64x64.jpg walkereng's Avatar

    walkereng

    Consultant

    Satisfied Customers:

    1396
    Over 28 years of Structural Engineering experience.
  • http://ww2.justanswer.com/uploads/VG/vgdlpc/2012-1-17_235838_VICENTEPHOTO.64x64.jpg vgdlpc's Avatar

    vgdlpc

    Master's Degree

    Satisfied Customers:

    17
    Civil Engineer, Major in Structures and Foundations. Professional Engineer 11 years of experience.
  • http://ww2.justanswer.com/uploads/ST/StructuralEng/2013-9-10_61545_struct.64x64.jpg StructuralEng's Avatar

    StructuralEng

    Consultant

    Satisfied Customers:

    3364
    Structural Engineer
  • http://ww2.justanswer.com/uploads/35/350matt/2012-6-7_182356_matsavatr.64x64.jpg Matt's Avatar

    Matt

    Engineer

    Satisfied Customers:

    16
    Mechanical Engineering Hons degree, been working in automotive industry for the last 18 years - Engine development engineer
  • /img/opt/shirt.png ibosley's Avatar

    ibosley

    Master's Degree

    Satisfied Customers:

    88
    Mechanical Engineering
  • http://ww2.justanswer.com/uploads/FL/FLAandNYLawyer/2012-1-27_14349_3Fotolia25855429M.64x64.jpg FiveStarLaw's Avatar

    FiveStarLaw

    Consultant

    Satisfied Customers:

    108
    attorney and legal researcher