Replies

1. 
   jimblodgett | Aug 22, 2015 02:18pm | #1

   None of this sounds good to me, not even the original premise you can span 16' with a 2x10. 

   As for the sistering I say hell to the no. No way you're gonna show me any math, or span chart, or engineer's stamped approval that changes my mind. Don't do it. Bad idea and it would be even worse craftsmanship. 

1. 
   deadnuts | Aug 22, 2015 04:58pm | #3

   not so fast...

   jimblodgett wrote:

   None of this sounds good to me, not even the original premise you can span 16' with a 2x10. 

   Jim, with all due respect, you don't know the perameters the O.P. is basing his statement on. IMO, more info is needed before making such a statement as above.

   In fact, Table R502.3.1(2) of the IRC, states that a 2x10  #2 Hem-fir  (very common) floor joist at 16" O.C. for residential living area @ 40 psf LL with a L/360 def is alllowed to span 15'-2". Granted, he's not quite there with what the big box stores usually stock...but if the O.P. was to order a #2 S.Y. P from a decent lumber yard (not too difficult to get in most places) he would be allowed to span 16'-1". Bump that to a #1 grade (still pretty common, if pricey), then he is allowed to span 16'-9" by prescriptive code. And that's just one of the most common applications for a 2x10 span. There are other appliations in the presriptive code for floor joists (not to mention rafters) that allow even longer spans of almost 20'.

   Just sayin.

   As for the latter premise: he can't go there with prescriptive code. I'd recommend the O.P. hire an engineer if he'd like to entertain those ideas. IMO, he's wasting everyone's time on this forum soliciting those kind of thoughts or ideas.

1. 
   jimblodgett | Aug 23, 2015 11:17am | #8

   Deadnuts - I'll stand by what I said. 16' span for 2x10 floor joists doesn't sound good to me. I wouldn't do it, regardless of span tables, code requirements, engineer's specs, grade or species of lumber.  I have spent the majority of my career building in the Great Northwest, land of Douglas Fir aplenty, and I might (stress "might" here) use #1df 2x12, but it would keep me awake at night. First choice would be 2+1/4"x12" I-joists, but of course that wasn't what Chris asked.

   No. He asked for opinions, I gave mine. 

1. 
   deadnuts | Aug 23, 2015 11:42am | #10

   And I stand behind what i said: The O.P. did not provide enough information to support your "opinion"--and certianly not the premise that he was only talking about floor joists.

   In fact, he later stated there was no specific application. If you want to emphasize sticking to what Chris asked, then the least you could do is follow suite.Your opinion that we're specifically talking about floor joists is simply your imagination. The IRC code allows for 2"x10" spans of 16' and greater under certain circumstances (both floor and roof). It doesn't matter where,  how long, or how you've built anything; that fact doesn't change. Personaly, I couldn't care less what (or what doesn't) keep you up at night.

2. 
   BossHog | Aug 22, 2015 04:25pm | #2

   Like Jim said - Bad idea.

   More expensive than using one single joist, and there's no point in it.

3. 
   DanH | Aug 22, 2015 10:13pm | #4

   Code aside, you can make it work, maybe with a 6-foot sister, certainly with an 8-foot one.  The fastener schedule would be critical, of course, and I suspect the spliced beam would not develop quite the strength of a single beam due to the stress concentration at the splice point.  In fact, it would likely make it a bit stronger if there were a gap of maybe 2 feet between the board ends.

   Another way to approach it would be to splice a 4-foot piece on each end of an 8-footer.  This would likely be stronger than the other way because the stress-concentrating splices would be away from the center (where stress is highest).  Or go all the way and sister two 8-footers with a 4/8/4 trio -- would be nearly twice as strong as a single piece.

   But, of course, the trick is to get any of this approved.  And to keep some parties here from calling down hellfire and damnation on you for even thinking about it.

1. 
   deadnuts | Aug 23, 2015 12:17am | #6

   maybe, suspect, likely, blah, blah, blah...

   DanH wrote:

   But, of course, the trick is to get any of this approved.  And to keep some parties here from calling down hellfire and damnation on you for even thinking about it.

   It's not a trick, but usually an impossiblity. That's why hiring a professional engineer and not spewing dead end conjecture is the best course of action. Dan knows this, but simply can't help himself with entertaining the latter.

   If this bozo wants to empirically find a solution to a nonsensical problem while entertaining (and perhpas endangering) himself and others, then go for it. He can waste some time, some lumber, and some bolts to see what floats his boat. Heck, if he throws enough material, bolts, tape, and bubblegum at the problem he might just stumble upon a solution that actually works. However, don't expect that approach to fly for everyone on this forum without some blowback.

4. 
   deadnuts | Aug 22, 2015 11:57pm | #5

   CHRISWALL wrote:

   The real question is : If it needs to be done how should it be done?

   and yes I may not be using the correct terminolgy hence the " ".

   Wanna play?

   Sure. The real answer is you need a professional engineer to provided the proper structural solution for the question you pose. You're obviously not one.

5. 
   CHRISWALL | Aug 23, 2015 07:36am | #7

   Ah yes Us BOZOs should hire a professional in all cases.

   Like the "professional" achitect that designed my house with inadaquate duct work to the second floor>

   Or the "professional" HVAC company that left a 6" hole in the duct (hidden from view of course)

   Or the "professional" roofer who didn't glue the that Hard to reach corner on the rubber roof ( $15,000 repair)

   Or the "professional" builder who didn't tape any of the tyveck seams

   Or the "professional" inspector who signed off on it all.

   Shall I continue?

   Just trying to learn how to do something so I can tell if the "professional" is an idiot or not

   Now I could hire an engineer for $500 on a $200 project and if he told me to do this I'd have to believe him, 'cause he's got a stamp

   BTW how did they build a barn 100 years ago without a stamp? 

   "we're all BOZOs on this bus";  Firesign theatre

   Play time's over,  back to work  ( I get paid to work  that makes me a "professional" too.)

1. 
   deadnuts | Aug 23, 2015 11:23am | #9

   Apparently you hired wth wrong professionals.

   Disreputable professionals don't stay in business long. Reputable professionals stand behind their work with licensing, insurance, certifications, good referrels, and warranties.  It takes due diligence to weed the good professionals out from the bad. That means work. Apparently you weren't up for that effort and paid the price.  IMO, that's what you should focus your efforts on in the future. If you want to learn how to be professional engineer, then go ot school and earn the credentials to practice the profession. I guarantee you won't learn it here on this forum.

6. 
   mark122 | Aug 23, 2015 10:47pm | #11

   Hey dumbnuts...

   you forgot to take your meds again. You shouldnt get off your lithium like that.