# Span tables for 8"x12"x24' western red cedar for this pergola



## The Coastal Craftsman

Hey guys im trying to find some span tables for material this size. 

Trying to design a pergola for a customer and having trouble finding any specs for this material. 

Basically i need to find out if this is gonna be beefy enough to handle the structure of the pergola.

Posts are 8x8
Beams are 8x12x28 but span is 24ft 
Upper rafters are 2x12x28 but span 24ft


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## griz

In my experience any type of Cedar sawn lumber does not make a good choice for structural members.

Cedar glu-lams work very well.

See if there is any info here that is helpful:

http://www.realcedar.com/architects/engineering-data/

http://www.realcedar.com/wp-content/uploads/2013/06/WRCLA_Designers_Handbook.pdf

http://www.bearcreeklumber.com/employeepages/PDFs/wwpaWesternLumberSpanTables.pdf


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## The Coastal Craftsman

griz said:


> In my experience any type of Cedar sawn lumber does not make a good choice for structural members. Cedar glu-lams work very well. See if there is any info here that is helpful: http://www.realcedar.com/architects/engineering-data/ http://www.realcedar.com/wp-content/uploads/2013/06/WRCLA_Designers_Handbook.pdf http://www.bearcreeklumber.com/employeepages/PDFs/wwpaWesternLumberSpanTables.pdf


Thanks Griz I will take a look through them.


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## Fouthgeneration

Get a Structural Engineer, do what You know how to do, study the engineer's method for the next one..

2" Laminated lumber would have much higher # for design strengths.
Roanoke, 90 Mph wind loads and snow loads, with severe weathering....

run the posts continuously through the roof to top of deck, stronger, more room for connections and provides some shear.

Where are the diagonal braces for any of the three dimensions? X,Y & Z?
Can the chimney withstand any surplus loads?


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## Windwash

Ate at restaurant today that was building an outdoor eating area and thought of this thread as I just read it a couple nights ago. Agree with others that engineer is needed.


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## Okiecontractor

Ever get that figured out Barri? Ive built several pergolas gazebos and outdoor kitchens. Some being basically the same size.


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## The Coastal Craftsman

Gave the plans and estimate to the owners of the apartments. From what I have read the spans are ok but if I get the job I'm gonna dial it in with the engineer.


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## Okiecontractor

Cool. I know you know what you're doing but let me know if I can help. I used 4x12s on some of the stuff though. Not just 2xs.


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## Okiecontractor

Scratch that.. I misread your post.


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## The Coastal Craftsman

Lol this stuffs the big stuff. I will give an update though if I get the job. Gonna need a bit of advice on this one for sure.


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## tjbnwi

2 ply 4x12 Select Western Red Cedar- 24'span 100 pounds per foot evenly spaced load gives you an L360 ceiling. It will deflect 0.807 at mid span. 

2x12 No. 1 Western Red Cedar span 24' 10 pounds per foot evenly spaced load, will deflect 0.414" mid span. About L 480.

Even as "the big stuff" light comparatively.

Tom


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## The Coastal Craftsman

tjbnwi said:


> 2 ply 4x12 Select Western Red Cedar- 24'span 100 pounds per foot evenly spaced load gives you an L360 ceiling. It will deflect 0.807 at mid span.
> 
> 2x12 No. 1 Western Red Cedar span 24' 10 pounds per foot evenly spaced load, will deflect 0.414" mid span. About L 480.
> 
> Even as "the big stuff" light comparatively.
> 
> Tom



That sounds like good news then so shouldn't have to change my plan or layout.


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## tjbnwi

I used full size not nominal. That is how most of the cedar comes around here.

Tom


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## Okiecontractor

Thats how it comes here too.


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## Philament

Did you ever go forward with this project? I'm very interested to know what loading characteristics you or your engineer used for determining the span for an outdoor structure. I have a love for timber framing would really like to get into building outdoor structures like this. 

I can't quite tell by the drawing if this is a free standing pergola, but if it is, I would think that sizing the bracing almost be more important (beams can sag, but if the wind blows it over...). Maybe by letting in the 2x12 rafters and adding let in purlins you could stiffen it up. 

In the appendix of Ted Benson's "Building The Timber Frame House"(http://www.amazon.com/Building-Timber-Frame-House-Forgotten/dp/0684172860/ref=sr_1_1?ie=UTF8&qid=1418660367&sr=8-1&keywords=building+the+timber+frame+house+tedd+benson) he has step by step calculations in layman's terms on how to size beams for timber framing, but you need to know the loading characteristics first. Great book though if you're into working with timbers. 

Before doing this for a living I fixed a few barns did some retrofit bents, a few pergolas with friends, but 8x12" with cedar for that span seems a little small from what I've seen. The 16' opening bent that we did was 10"x10" douglas fir and most of the barn beams were 8x8, 10x10 and even 12x12 oak with spans rarely exceeding 16'.... all depends on loading though.

Looks like a really fun project, hopefully it goes ahead!


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## The Coastal Craftsman

Philament said:


> Did you ever go forward with this project? I'm very interested to know what loading characteristics you or your engineer used for determining the span for an outdoor structure. I have a love for timber framing would really like to get into building outdoor structures like this.
> 
> I can't quite tell by the drawing if this is a free standing pergola, but if it is, I would think that sizing the bracing almost be more important (beams can sag, but if the wind blows it over...). Maybe by letting in the 2x12 rafters and adding let in purlins you could stiffen it up.
> 
> In the appendix of Ted Benson's "Building The Timber Frame House"(http://www.amazon.com/Building-Timb...s=building+the+timber+frame+house+tedd+benson) he has step by step calculations in layman's terms on how to size beams for timber framing, but you need to know the loading characteristics first. Great book though if you're into working with timbers.
> 
> Before doing this for a living I fixed a few barns did some retrofit bents, a few pergolas with friends, but 8x12" with cedar for that span seems a little small from what I've seen. The 16' opening bent that we did was 10"x10" douglas fir and most of the barn beams were 8x8, 10x10 and even 12x12 oak with spans rarely exceeding 16'.... all depends on loading though.
> 
> Looks like a really fun project, hopefully it goes ahead!





Thanks man I will take a look. Posts will be on the ground so should help it be a bit more stable. It's still going through the company's budget people. Kind of hope I don't get it as it's way more than I have ever taken on before but would def teach me some stuff.


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## Jayhawk builder

Can I span a cedar 4x12 16'?
Roof load only.


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## thehockeydman

Jayhawk builder said:


> Can I span a cedar 4x12 16'?
> Roof load only.


"General contractor"?


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## asevereid

Everyone always gets to be "General Contractor"... When I go out on my own, I'm going to be" Colonel Contractor ". I think the alliteration will be highly marketable. 
Until then, I will continue to be" Captain Carpenter ".


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