# Maximum Beam Span to support a Shed Roof?



## rk-nc (Oct 11, 2010)

I am planning to extend my front porch (currently 5' deep) to 10' from the house. My plan is to build a shed roof ... the new pitch will be on the order of 3/12.

With the posts set 10' from the house, what is the maximum beam span between the posts? for 2x10s or 2x8s?

I'm hoping that I can get buy (for aesthetics) with only four posts two in the corners and two equally spaced between w/ ~13.5' spans.


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## wombosi (Apr 22, 2008)

rk-nc said:


> I am planning to extend my front porch (currently 5' deep) to 10' from the house. My plan is to build a shed roof ... the new pitch will be on the order of 3/12.
> 
> With the posts set 10' from the house, what is the maximum beam span between the posts? for 2x10s or 2x8s?
> 
> I'm hoping that I can get buy (for aesthetics) with only four posts two in the corners and two equally spaced between w/ ~13.5' spans.


sorry, i read this wrong.
so you need to span 13.5' right? you'll need at least double 2X10s to meet code, i w ould think.
if you're doing it without a permit i'll tell you that 2X8s would not fall down, but may sag over time.

i gutted a porch recently that had as it's main header:

two pieces of 1X trim sandwiching an upper/lower 2X4 on the flat. it formed a "hollow" beam. this thing was spanning 10' and hadn't sagged since it was built probably 60 years ago. of course this would never pass code, and i would never advocate building anything this shoddy, but it just goes to show you you could get by with pretty much anything you wanted, assuming no permit.

if i'm still reading this wrong and all you need is a less than 7' span, than 2X8s are plenty.


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## Gary in WA (Mar 11, 2009)

Where are you located?
Any snow load?
What type roof covering? Tile, shake, shingle...
What is the rafter span?
Any overhang of roof at ends or tails?

Gary


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## Joe Carola (Apr 14, 2006)

schmolze said:


> sorry, i read this wrong.
> so you need to span 13.5' right? you'll need at least double 2X10s to meet code, i w ould think.
> *if you're doing it without a permit i'll tell you that 2X8s would not fall down, but may sag over time.
> *
> ...


Why would you even say this?

So this forum advocates giving structural advice based on whether someone is getting permits?

So, if your getting permits try to build it to code. If your not, you can use a smaller header that can possibly sag. Brilliant!!


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## wombosi (Apr 22, 2008)

joe carola, this is a "do-it-yourself" forum, not a "hire a structural engineer to tell you what will meet code" forum, which it seems to me what it's turning into lately.

i think it's a perfectly valid point to make. the OP wants to know what's the smallest size he can get away with. i was trying to illustrate that point, yet at the same time suggest the proper, code-abiding members.

i'm perfectly able to open my code book and spew out hard numbers if needed. at the same time, if i'm building something for myself, i wouldn't hesitate to do whatever the hell i wanted structurally. the final decision and responsibility is in the hands of the OP, and of everyone else who takes advice on here seriously.

my comments were purely for illustrative purposes and were meant to be taken with a grain of salt here.


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## Joe Carola (Apr 14, 2006)

schmolze said:


> guys, this is a "do-it-yourself" forum, not a "hire a structural engineer to tell you what will meet code" forum, which it seems to me what it's turning into lately.


What your saying is that since it's a diy'er forum they shouldn't get the right advice or professional advice and build whatever they want and listen to people giving them bad advice.

If this forum wants to be any help for a diy'er, they should always guide them in the right direction. Diy'er forums doesn't mean that you can just go build buildings yourself without finding out how to build it right and get proper permits and inspections so that the building is structurally sound.

Alot of diy'ers do not get permits and build anything they want and think it alright and ask on forums and get poor and dangerous advice. Then they run into problems and unsafe conditions.

I would not want to see that happen. You obviously don't care and are not doing these people any good by suggesting to frame with a beam that can sag. In care about people and want to suggest to the right thing and build something to code and safe. I've been framing for 27 years and still have a lot to learn, Diy'es cannot learn in a couple posts on the internet what's taken me 27 years to learn without being given the right advice.




> i think it's a perfectly valid point to make. the OP wants to know what's the smallest size he can get away with.


Yes, and your answer is to tell him to use a smaller beam that won't meet code and can probably sag. That's real smart. Your attitude is, who cares about the diy'er by not telling them the right thing to do.



> i was trying to illustrate that point, yet at the same time suggest the proper, code-abiding members.


Then don't suggest using a beam that will sag because these people might just do that. You should be telling them to ask their building department what the right thing to do is.


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## jlhaslip (Dec 31, 2009)

GBR in WA said:


> Where are you located?
> Any snow load?
> What type roof covering? Tile, shake, shingle...
> What is the rafter span?
> ...


can't add anything to this reply...:whistling2:


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