# Small Shed Roof 10'x12' Timber Recommendations 4:12



## Daniel Holzman (Mar 10, 2009)

I don't think I understand your plan. You say you want open rafters, with no joists and not trusses. The joists are installed to keep the walls from spreading. How do you plan to prevent the walls from spreading with no joists?


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## mae-ling (Dec 9, 2011)

On a 10 x 12 with a double top plate. there should not be much load so spreading should not be a problem. Proper adhesive and nailing of your gussets on both sides of each rafter helps too.


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## Daniel Holzman (Mar 10, 2009)

The OPS indicated he was building a shed. If he is in snow country, the roof will need to support the snow load. I live in MA, the snow load here is code mandated at about 35 psf (and we got it this year). No idea where the OPS lives, but a 120 sf roof at 35 psf would need to support 4000 lbs. Hence the need for joists.


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## mae-ling (Dec 9, 2011)

I am a carpenter and have built many sheds. So I come at it from a practical stand point.
That 4000lbs is spread over the entire roof the stuff at the gables and eaves really is not going to spread the walls, the stuff at the top center is going to have the most force.

I look at this sorta like a cathedral ceiling with scissor trusses. No straight across joists or bottom chord and the walls do not spread. A proper built rafter with a proper gusset would take care of it. IMHO.

This is just my experience and your mileage may vary.


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## bhollehday (Jan 30, 2015)

mae-ling said:


> I am a carpenter and have built many sheds. So I come at it from a practical stand point.
> That 4000lbs is spread over the entire roof the stuff at the gables and eaves really is not going to spread the walls, the stuff at the top center is going to have the most force.
> 
> I look at this sorta like a cathedral ceiling with scissor trusses. No straight across joists or bottom chord and the walls do not spread. A proper built rafter with a proper gusset would take care of it. IMHO.
> ...


I live in SoCal so not much of any snow here. :wink:

Thats exactly what I am looking for is an open cathedral style roof. I dont want lateral trusses running across, I want no attic, just an open roof. Like the picture seen below.

So I plan on building them just like the one seen in the picture. Taking two 2x6's and cutitng the birdsmouth on both sides, meeting the two together, and then cutting a gusset board for both sides to strengthen. (What size gusset board would you use? 5/8?) I wasnt planning on using a ridge board between the 24" spaced rafters. And Im also framing in a sunlight that is 4x4. So I would cut one rafter and frame it in, and the skylight would sit between the adjacent two rafters. 

For top seal plate, I have the walls up and nailed together, now I jsut take some more 2x4's and run them on top of the walls to help strengthen it?


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## Arky217 (Aug 18, 2010)

I usually build what I need, but recently I needed a small storage shed (8'x12') and after figuring the material cost would be more than I could buy one already built and delivered, I went with the pre-built one.

When they delivered it, I looked inside and noticed that it had gussets at the peak of the rafters like your picture, but no ceiling joists.

I also noticed that the side walls were already slightly bowed out (the shed had probably been sitting already built for perhaps up to a year).

So, what I did was to install just one ceiling joist midway from the ends to prevent any further bowing. You might consider that as an option.

Arky


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## 1985gt (Jan 8, 2011)

I did the same thing on mine, same dimensions. Only difference is I used a 2x8 ridge board. 

It's still standing...


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## mae-ling (Dec 9, 2011)

The thickness of the gusset really does not matter. I usually use 3/8" plywood. Run your double top plate and if there is a slight bow to the lumber have it curve inwards so as the wall pushes out at the top it straightens it if anything.


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## bhollehday (Jan 30, 2015)

ok sounds good guys. And I assume it would be best to use plywood instead of OSB for the gussets?

So ill be using 2x6's for the rafters, spaced 24" OC, add another layer of 2x4's for a seal plate on top of the walls (nothing special about cutting or strapping here right? Just adding another layer on top?), and a 2x6 ridge board (I wasnt going to use one, but since I plan on installing a 4x4" skylight on one side, maybe its best I use something).


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## mae-ling (Dec 9, 2011)

I Like to use plywood for the gussets, not sure if it really matters though.
The double top plate (seal plate) is just nailed on. I try to nail so my nails go into the stud but do not hit the other nails. This is more for running wires or water pipes later so the guy drilling does not hit a nail.

You could use a ridge board. Then your gussets will need an appropriate notch. Basically frame the rafters and add gussets after. 
I would double up rafters on each side of the skylight. Make sure you have the proper Rough Opening for it. Here is an idea on the framing for it.


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## funflyer (Dec 5, 2014)

Rather than go through the hassle of cutting gussets, I'd use collar ties if you are going to use a ridge board. A gusset would have to be installed below the ridge to do much good anyway and a tie would give better support to keep the center walls from moving outward.


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## bhollehday (Jan 30, 2015)

funflyer said:


> Rather than go through the hassle of cutting gussets, I'd use collar ties if you are going to use a ridge board. A gusset would have to be installed below the ridge to do much good anyway and a tie would give better support to keep the center walls from moving outward.


Thats a great option! I will consider that for sure. It might be nice as I could make a small storage area up there as well, although my idea was to keep it an open roof. Thanks for the idea!!


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## mae-ling (Dec 9, 2011)

Actually a ridge board is not absolutely needed with the gussets. But is not a bad idea with the skylight.


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## carpdad (Oct 11, 2010)

It is possible to use wall top plates as headers on side. If you use double 2x10 for example. Check the span charts. Just an idea.


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## bhollehday (Jan 30, 2015)

carpdad said:


> It is possible to use wall top plates as headers on side. If you use double 2x10 for example. Check the span charts. Just an idea.


Not sure im following you, cant picture the 2X10's. Do you have some pictures ?


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## ron45 (Feb 25, 2014)

while your still on the subject......
With the rafters spanning across the 12' foot side of the shed at a 4/12 pitch, the 2" by 6" will only span 6'-3 7/8" ( Diag) long before the overhang amount is calculated. The rise will be 2' feet, the angle is 18.43 deg.


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## carpdad (Oct 11, 2010)

Wall framing is made up of vertical studs and bottom and top pieces. Usually the top plates are same as the studs in dimensions, but if you replace the top plates with heavier lumber, the top can also serve as stronger structural part. It resists bending sideways, in this case the pressure that tie-less rafters will put on the walls.
Sorry that I can't figure out the specs but there must be a chart published online. I would start with the expected load on the rafter then look for header spec? Since it is not following the gravity down to a solid footing, I may pay for engineering the first time, ask questions, and may be confirm my question. That is probably the way I would go.

Your shed is smaller example, I may decide to use the strongest lumber (2x12 double) I know and over engineer it, and take my chances. 

Another way may be to use a structural ridge beam. I thought the support post at the door end can be reinforced with cross braces so that header size can be decreased. That is another question for the engineer.


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