Replies

1. 
   dieselpig | Dec 06, 2009 02:44am | #1

   My seventh edition MA code book is in the truck but if my memory serves me, 2x12 doug fir is ok.  It's snowing right now and I'm under a blanket watching 'bama and Florida so I'm not going to go get it either!  :)   Perhaps in the morning.

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1. 
   bsh6979 | Dec 06, 2009 03:11am | #2

   i check the seventh edition and it only goes to a span of 24' for ss# dug fur at 12" o.c. with out the ceiling attached would that mean the rafters should be micro lambs or even tgi's?

   Edited 12/5/2009 7:13 pm ET by bsh6979

1. 
   dieselpig | Dec 06, 2009 03:31am | #4

   Don't know... I'd have to look into it.View Image

2. 
   gdcarpenter | Dec 06, 2009 03:18am | #3

   You say they are hanging the ceiling joists off the rafters, the important question is how far 'up' the rafters are the ceiling joists attached.

   If the ceiling joists in the lower third of the height between the top of the double top plate and the ridge then there is probably not much 'significant' extra load. If they are higher up they are 'loading' the rafters and could require 'upsizing' of the rafters compared to a 'normal' span chart.

   Let's not confuse the issue with facts!

3. 
   Matt | Dec 06, 2009 03:42am | #5

   >> its spans 26'8" ridge to the seat cut <<

   So, the house is ~53' wide?

4. 
   Piffin | Dec 06, 2009 05:09am | #6

   WOW, that's a big house!

   spelling is doug fir BTW

    

    

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1. 
   Sphere | Dec 06, 2009 05:12am | #7

   It's 14' the other way, with wheels. 

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2. 
   bsh6979 | Dec 06, 2009 05:13pm | #8

   the pitch of the other side of the same ridge is a 10:12 its a very large shed dormer you could say.

1. 
   Piffin | Dec 06, 2009 10:13pm | #9

   I am probably even more confused now, but can't reaqlly comment with out photos and drawings I guess. It does SOUND like you are right about it being overspanned.... 

    

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1. 
   jimblodgett | Dec 06, 2009 10:49pm | #10

   I'm wondering about supporting the ridge. 

1. 
   Piffin | Dec 06, 2009 11:10pm | #11

   I'm wondering if there even is a ridge beam, or if it is just a ridge board.Seems they require engineering designs down there in Mass 

    

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2. 
   bsh6979 | Dec 07, 2009 04:04am | #22

   the ridge beam was a triple 18" micro lamb. i thought that it was a little over kill on the ridge beam but they undersized the rafters. they dont show that span in the code book for a any "wood" rafter.

3. 
   Piffin | Dec 07, 2009 04:14am | #23

   sizing of that lam beam tells nothing without knowing how long it is and if it has any intermediate support.but from the minimal info so far, sounds like you are right. 

    

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4. 
   bsh6979 | Dec 07, 2009 04:32am | #24

   the span is 25' with no center suport under the ridge beam.

5. 
   Framer | Dec 06, 2009 11:36pm | #12

   >> its spans 26'8" ridge to the seat cut they are also hanging the ceiling joist off the center of the rafters. <<

   What did you use to span 26'8" ceiling joists?

   >> i know this cut down on the span a little. its 16"o.c. structural dug fur 2 x 12. the pitch of the roof is a 4:12. <<

   You have a 26'8" span with a 4/12 pitch. That means your rafter is roughly 28'1" without any overhang. Who designed this?

   >> the pitch of the other side of the same ridge is a 10:12 its a very large shed dormer you could say. <<
   You're butting the new rafters into the existing ridge that has a 10/12 pitch on the other side? This sounds like a Cape Cod roof with a 10/12 pitch and you cut the back roof out and frame walls and a shed roof dormer into the 10/12 existing ridge. Only your span is 26'8"? That's sounds like a huge house.

   Joe Carola
1. 
   bski | Dec 06, 2009 11:46pm | #13

   i think by span he meant the rafter length was 26'8".  

   Edited 12/6/2009 3:47 pm ET by bski

1. 
   Framer | Dec 07, 2009 12:43am | #16

   >> i think by span he meant the rafter length was 26'8". <<That would make the rafter run(to ridge in plan view) 25' 3-9/16" with a 4/12 pitch. Joe Carola

6. 
   Gene_Davis | Dec 07, 2009 12:02am | #14

   I'm an engineer, but I am not your engineer.  You may want to discuss this with a local pro, or someone that knows her stuff at your AHJ.

   For starters, one might check this out.  http://www.awc.org/calculators/span/calc/timbercalcstyle.asp

   And I am stupefied to think that a roof with a span like you describe is being framed with site-cut sawn lumber at all.  With the info you have provided, I am surprised that you would even consent to work on it, or even consider going under it.

    

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1. 
   Framer | Dec 07, 2009 12:27am | #15

   >> And I am stupefied to think that a roof with a span like you describe is being framed with site-cut sawn lumber at all. With the info you have provided, I am surprised that you would even consent to work on it, or even consider going under it. <<Gene,In framed an addition last Spring with 30'Doug Fir 2x12's, 7/12 pitch as per Architect and Engineered drawings.Joe Carola

1. 
   Gene_Davis | Dec 07, 2009 12:54am | #17

   And your snow loading is?

   And you'll climb up on anything your foreman engineers?

    

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   "A stripe is just as real as a dadgummed flower."

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   Edited 12/6/2009 4:56 pm ET by Gene_Davis

1. 
   Framer | Dec 07, 2009 12:57am | #18

   >> And you'll climb up on anything your foreman engineers? <<What foreman?Joe Carola

1. 
   Gene_Davis | Dec 07, 2009 01:35am | #20

   OK, how about the OP's foreman?

   The one who's engineering is being questioned here.

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   "A stripe is just as real as a dadgummed flower."

   Gene Davis        1920-1985

   Edited 12/6/2009 5:36 pm ET by Gene_Davis

2. 
   Framer | Dec 07, 2009 07:11pm | #28

   >> OK, how about the OP's foreman?
   The one who's engineering is being questioned here. <<I wasn't responding to you with that.I was responding to what you said here.>> And I am stupefied to think that a roof with a span like you describe is being framed with site-cut sawn lumber at all. With the info you have provided, I am surprised that you would even consent to work on it, or even consider going under it. <<As far as the OP's playing engineer, I think he's a moron. That would never happen on my jobsite. I make suggestions all the time, if an Architect or Engineer like what I say or think it makes sense, they can do what they want with it. Ultimately it's their decision what the house gets built with not mine.Joe Carola

   Edited 12/7/2009 11:12 am ET by Framer

2. 
   Gene_Davis | Dec 07, 2009 01:01am | #19

   See attached.  Loadings matter.  Pitch plays a small role.

   This is just a quick look from a table, essentially.  No attempts were made to analyze the actual structure, its siting, connections, bearings, etc.

   Select structural lumber takes it up a little.

    

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   "A stripe is just as real as a dadgummed flower."

   Gene Davis        1920-1985

   Edited 12/6/2009 5:03 pm ET by Gene_Davis

3. 
   Timuhler | Dec 07, 2009 05:35am | #25

   Joe,

   How was the quality of those 30' 2x12s?  The house below had some 28' and some 30' in front and they were very high quality.  We were able to lift the 28' w/out much trouble.  I'd get them over my head to Matt on the ladder and then help him push them up to the ridge.  It wasn't too bad.

    

    

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1. 
   Framer | Dec 07, 2009 05:44am | #26

   They were in great shape. Doug Fir is all we use. I've never seen anything different in NJ. I carried 4 at a time and just threw them up to the ridge......;)Joe Carola

1. 
   Timuhler | Dec 07, 2009 05:59am | #27

   4 at a time!!!???  you are getting weak old man, time to pass the torch to little Joeyhttp://www.pioneerbuildersonline.com

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2. 
   dieselpig | Dec 08, 2009 05:05am | #29

   I carried 4 at a time and just threw them up to the ridge......;)

   :)View Image

2. 
   bsh6979 | Dec 07, 2009 04:02am | #21

   The rafters are being cut from 2x12 dug fir from the local lumber hard. there was never and Eng. involved with the drawings. that was my argument. that they are veteran carpenters but that still doesnt give them the legal right to make the choice. i checked my code book and the span tables don't go past 24'6" for any type of spacing or type of wood. that's why i challenged the foreman. I don't want the owner coming down on the crew like there inferior. i think someone is just being lazy and cheap. I forgot to tell you the ridge beam is a triple 18" micro lamb. the house was best described as a cape house. I will post pics tomm.

7. 
   Jeff_Clarke | Dec 10, 2009 08:53pm | #30

   No offense - you *are* measuring horizontally, right? Not along the slope of the rafter ...

   Jeff