Author Topic: beam size  (Read 4001 times)

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Offline ollie

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beam size
« on: January 26, 2007, 02:46:08 PM »
The Victoria cottage. 6x8 beams for the loft floor? Are they on 48" centers? Solid douglas fur beams would be expensive to have shipped in. I could get oak at a local saw mill but I am guessing they would be expensive. Would gluing four 2x8 or 2x10 and maybe bolting them together every three or four feet be an acceptable alternative?   Would this be strong enough for the 16' span and still be a sturdy loft floor?    Thanks, Ollie

Offline John Raabe

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Re: beam size
« Reply #1 on: January 27, 2007, 09:08:55 AM »
Working with the loft plan on sheet 3 you will notice that the MAX span between beams is 48". Over the areas where the span is full width the beams are spaced to divide the spans equally. This is less than 3' span between beams.

Doing a new calculation using a loft live load of 30 lbs/SF (main floors are 40) I see you could use a built-up beam of 4 2x8's and it could span 15' (the working span of a 16' wide building) at a max spacing of 48" o/c using Fir, Larch, or Southern Pine #2 or better. The limiting factor here is not strength but deflection (bounce). The above calculation was done with 1/240 deflection. If you wanted less deflection then use 2x10's or cut down the span between beams to something like the 3' shown in the plan.

In other words you could replace 6" built-up beams for the solid 6x's shown in the plan
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Offline PEG688

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Re: beam size
« Reply #2 on: January 27, 2007, 09:11:50 AM »
I'd check the price of those 6x6's before I'd start dbling up.

 I'd think you could do 2x10's or 12's , maybe like this ,

  

 Dbl'ed on either side of a 4x6 LVL , or in some cases D Fir 4x6.

 Could be the height's won't work in your case , John should answer this one maybe he'll see it once it's bumped.

  Edited to add he saw it before the bump :) Good job John ;)

 G/L
 PEG  
« Last Edit: January 27, 2007, 09:12:51 AM by peg_688 »
When in doubt , build it stout with something you know about .

Offline youngins

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Re: beam size
« Reply #3 on: January 28, 2007, 03:51:06 PM »
PEG,

Is that a 2x4 going left to right, notched into the wall studs holding up the joists?

Thanks,

Chris
"A spoonfull of sugar helps the medicine go down.."

Offline PEG688

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Re: beam size
« Reply #4 on: January 28, 2007, 04:14:31 PM »
Quote
PEG,

Is that a 2x4 going left to right, notched into the wall studs holding up the joists?

Thanks,

Chris


 It's a 2x6 , and yes it's let in 1 1/2" . Here's the link to the total thread which you should read IF you are getting a permit and following IRC 2003.

 It's a long storey which you may find interesting.

 Link:http://www.countryplans.com/cgi-bin/yabb2/YaBB.pl?num=1144724922/10#10

 The short answer is yes ,

  

 That old thread has the whole storey on how , why , plus so much more  ::)

 G/L PEG :)
« Last Edit: January 28, 2007, 04:18:24 PM by peg_688 »
When in doubt , build it stout with something you know about .

ollie

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Re: beam size
« Reply #5 on: January 31, 2007, 01:57:45 PM »
Thank you all. I am just trying to get my game plan together. I really like this site and have allready learned alot.     Ollie

ollie

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Re: beam size
« Reply #6 on: January 31, 2007, 03:30:44 PM »
I just read the link from PEG688 and am wondering about notching the 2x6 walls 1.5" for the 2x10 band joist. Manhattan42 said it was not allowed in the International residential code to notch deeper than 1 3/8" in a 2X6.  Is this correct?  The Victorias cottage plans are drawn this way. Just covering all the bases.
                                                                                                                               Thanks,  Ollie

peg_688

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Re: beam size
« Reply #7 on: January 31, 2007, 04:16:34 PM »
Yes Ollie that's what it sez , the job I did had engineering that over rode the basic code , the prescriptive code.

 The way around it I see would be to run a 2x thru a surface planer and thin it up to 1 5/16" to satisfy the gestapo/ building official .

  Or use a 1x 6 or 8 , I'd we used that on the next job we did. This , to me , seems to be a wrong way "fix " but it did fill in / make the ledger "fit" into the STUPID prescriptive code :-[ >:( :(


 You can see the 1x6 ledger in the upper left corner of this photo , the same techniques where used , the depth just changed and it fits the code ::) Which I believe I mentioned is STUPID! ;D No engineering was required for this structure. Read less $$$ those engineers really know how to charge  :o

  
  
« Last Edit: January 31, 2007, 04:34:52 PM by peg_688 »

ollie

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Re: beam size
« Reply #8 on: February 01, 2007, 09:52:51 AM »
Could you just notch the wall stud 1 1/4" and then the back of the 2x band joist 1/4" ? Would this still be strong enough to mount the beams with hangers to?

peg_688

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Re: beam size
« Reply #9 on: February 01, 2007, 03:32:02 PM »
IMO yes that would work. It would be a lot more work doing the dap to the back of the ledger along with the stud knotching ,  but yes it should work , it would be plenty strong :), Ask your local insp. he could see / interpret it differently :(

 G/L PEG

 

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