woodgeek
Registered Users
Posts:8
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| 06/03/2008 1:24 PM |
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Hello all,
I'm drawing up plans for a ~1500 sq ft house. It will be a one story, on slab with either a timber frame structure with staw bale infill or faswall walls with exposed timber frame joists; relatively basic 24' x 64' rectangular footprint. My question is what type of span can I get out of the 8 1/4" SIPs (I want to go with the OSB variety). I know that I may have some enginnering restrictions, but curious if I can do 12' on center between the timber frame members/
thanks
Carl
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Alton
Registered Users
Posts:308
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| 06/03/2008 2:11 PM |
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Carl,
Assuming that you are talking about spans on a roof, then what pitch will the roof be? |
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Alton C. Keown
Residential Designer and Construction Technology Consultant
Auburn, Alabama
334 329-0957 AT&T Cellular |
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woodgeek
Registered Users
Posts:8
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| 06/03/2008 2:28 PM |
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correct - spans on a roof. Probably 12/4 but maybe 12/2 -- either a flat or gable style. roof size would probably be around 68' x 28' (2' overhang)
thanks!
Carl
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Alton
Registered Users
Posts:308
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| 06/03/2008 3:48 PM |
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Carl,
Be aware that low pitch roofs require more support than steep roofs. If I am reading your pitch correctly, then your roof will be a very low pitch which may require a metal roof. In the Southeast, we refer to the pitch you mentioned as 2 to 12 or 4 to 12 where the first number is the rise and the second number is the run (rise over run). Maybe some of the panel companies can now give you an idea about the span between supports. Of course, snow and wind loading will have to be considered. |
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Alton C. Keown
Residential Designer and Construction Technology Consultant
Auburn, Alabama
334 329-0957 AT&T Cellular |
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Structures NW
Registered Users
Posts:1
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| 06/03/2008 4:05 PM |
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The guideline I use in the NW where I need a min 50 lb total Load is
6" will span 8ft
8" will span 10ft
10" will span 12ft
12" will span 14 ft
Will they span farther yes a little with out putting lumber of I-joist into them.
I ALWAYS place the supports below the panels NOT in them.
Whenever possible I use a beam rafter design as opposed to a purlin so you can stack the panesl up the roof.
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woodgeek
Registered Users
Posts:8
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| 06/03/2008 4:13 PM |
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Alton - thanks -- yep you're right, I wasn't sure how the rise/run designation was worded.
Thanks for the info Structures NW - that helps!
Carl |
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PanelCrafters
Registered Users
Posts:1323
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| 06/03/2008 4:23 PM |
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Posted By Structures NW on 06/03/2008 4:05 PM
I ALWAYS place the supports below the panels NOT in them.
Whenever possible I use a beam rafter design as opposed to a purlin so you can stack the panesl up the roof.
Hmmm. It sounds like you sacrifice the functionality of SIPS for the ease of installation. Are you trying to force a product into a place that it shouldn't be? Extra structure, is extra cost. Isn't that(less framing) the point of using SIPS in the 1st place? |
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....jc
If you're not building with OSB SIPS(or ICF's), why are you building? |
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cmkavala
Registered Users
Posts:808
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| 06/03/2008 4:32 PM |
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For those interested steel geeks:
with 50lb. total load;
4" will span - 11.5 ft
6" will span - 18 ft.
8" will span - 20 ft. |
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Chris Kavala
chris@southernsips.com
1-877-321-SIPS |
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Alton
Registered Users
Posts:308
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| 06/03/2008 9:05 PM |
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PanelCrafters,
What is your latest thinking regarding long-term creep with long-term snow loads on OSB SIP roofs? Some of the last lectures I attended on SIPS did not address this throughly enough for me. |
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Alton C. Keown
Residential Designer and Construction Technology Consultant
Auburn, Alabama
334 329-0957 AT&T Cellular |
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PanelCrafters
Registered Users
Posts:1323
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| 06/04/2008 7:13 AM |
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Posted By Alton on 06/03/2008 9:05 PM
PanelCrafters,
What is your latest thinking regarding long-term creep with long-term snow loads on OSB SIP roofs? Some of the last lectures I attended on SIPS did not address this throughly enough for me.
Alton,
From what I understand(and I'm no engineering expert), SIPS are likely to creep over time, and the extent is really an unknown. I have heard that in areas with varying humidity levels that creep is likely to me more pronounced. I'm sure that snow loads don't help! |
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....jc
If you're not building with OSB SIPS(or ICF's), why are you building? |
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woodgeek
Registered Users
Posts:8
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| 06/06/2008 4:17 PM |
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ok, I'll expand a little on what I'm trying to figure out. I'll be the first to admit that I'm a bit of a newbie with roof design, but my current design uses SIPs to cover a 24' x 64' footprint with a 1 in 12 pitch (with 2' overhangs all around). I want to use exposed rafters in my design. Looks like rough calculations would be about $10k for the SIPs and I like the Eco-shakes. I have no real idea how many rafters or what size I'd need to cover this span or if this is even doable (or is but very expensive). I'd probably nail up T&G up to the ceiling.
Any feedback would be appreciated -- I still in the design phase so not necessarily looking for details but rough ideas would help.
Thanks
Carl |
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PanelCrafters
Registered Users
Posts:1323
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| 06/06/2008 7:41 PM |
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| Where are you building? IE, what R-Value are you looking for? |
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....jc
If you're not building with OSB SIPS(or ICF's), why are you building? |
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woodgeek
Registered Users
Posts:8
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| 06/06/2008 8:13 PM |
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I'm in NW Washington state, I forget the actual R-Value I'm looking for as I'm away from my notes. I do remember looking at the ~8" panels though.
Thanks
Carl
fyi... doing further research I'm now looking at using Faswall for the walls and doing a conditioned crawl space if that has any impact... |
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PanelCrafters
Registered Users
Posts:1323
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| 06/06/2008 8:37 PM |
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Posted By woodgeek on 06/06/2008 8:13 PM
I'm in NW Washington state, I forget the actual R-Value I'm looking for as I'm away from my notes. I do remember looking at the ~8" panels though.
Ok, cool. You may need need to add a grand or 2 to your budget. The panels only need to extend to the outside of the exterior walls. Rafter tails can handle the overhangs.
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....jc
If you're not building with OSB SIPS(or ICF's), why are you building? |
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woodgeek
Registered Users
Posts:8
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| 06/06/2008 8:50 PM |
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thanks jc -- so an extra 1-2k for the SIPS?
c. |
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PanelCrafters
Registered Users
Posts:1323
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| 06/06/2008 9:01 PM |
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Posted By woodgeek on 06/06/2008 8:50 PM
thanks jc -- so an extra 1-2k for the SIPS?
That's a rough estimate, yes. But, everything is 'going thru the roof' right now due to energy costs... |
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....jc
If you're not building with OSB SIPS(or ICF's), why are you building? |
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