Shed Structure - Need advice please

[sooperdoosher]

All,
I have a 12x10 shed under construction and believe the roof structure is too weak. It's at my brother's house in St. Louis and will incur snow/wind.

Here is the current design (already framed as shown in photo)
--The roof spans 12'
--Rafters are 2x4's at 24" OC, with 16" 2x4's to tie them at the top and a 2x4x12' spanner.
--The roof rises 4'
--Sheathing is .5" OSB, and rises 4'.
--Walls are 2x4's at 24" OC

My plan is to strengthen the roof from downward and lateral forces by adding two 2x6 beams from front to back by placing them under the rafters and support them from the front and rear wall plates as well as tie them into the walls (on the wall plate to compete against down force, tie to walls for lateral force)

Any other/better ideas?

Thanks!!!

 

[Hot Rod Grampa]

You have a 8/12 roof pitch and that is significant. Not much snow will linger. Other than truss clips tying the rafters to the top plate I see no worries. Hope this helps.

 

[T_R]

Sounds good to me. I just built a 12x12 building the same way. 24 OC 2x4 rafters, 2x4 rafter ties with 7/16 osb is a normal construction method for a building of that size.

I can't tell from your pictures how your rafters are cut. Do you have a ridge beam in there and a birdsmouth on the rafter at the top plate?

You have too much unsupported overhang on your gables. You need ladders under there.

 

[sooperdoosher]

Thanks for the advice. I don't know what a birdsmouth is, but do not have a ridge beam.

I do have 16" 2x4's screwed into the top of the rafters to tie them together.

 

[The Cobbler]

can you show more pictures?
I'm thinking(from what I can see ) that the roof structure is not framed very well for snow loads. looks like very little to keep them from "flattening & pushing out" if that makes any sense
purely constructive criticism, not poking a jab at anyone

 

[D45]

I built a 10x12.........2x4s with 12" OC

 

[T_R]

Thanks for the advice. I don't know what a birdsmouth is, but do not have a ridge beam.

I do have 16" 2x4's screwed into the top of the rafters to tie them together.

Birdsmouth is the notch you make for the rafter to sit on the top plate. If you didn't prebuild trusses and you just set the rafter on the top plate and toe nailed it down, you are going to have to take the roof down and redo it.

If you post pictures of what you have so far we can give you better advice.

 

[Bretny]

2x4 rafters should never be in snow country. 24in OC should never be in snow country.
Adding the 2x6 beams should help quite a bit. Also add collar ties.
I would make the 2x6 beam out of two 2x6 with 1/2in plywood in between. 2x6 is kind of small to run 10ft, even if you double it up. With all this wood your adding trying to fix a probem you could just built it correctly.

I built a 13x19ft shed with a gambrel roof. The second story is 7fy tall inside. I used real rough cut 2x6 rafters 16in OC. The gambrel truss runs the 19ft width.

 

[ItsNemo]

2x4 rafters should never be in snow country. 24in OC should never be in snow country.
Adding the 2x6 beams should help quite a bit. Also add collar ties.
I would make the 2x6 beam out of two 2x6 with 1/2in plywood in between. 2x6 is kind of small to run 10ft, even if you double it up. With all this wood your adding trying to fix a probem you could just built it correctly.

I built a 13x19ft shed with a gambrel roof. The second story is 7fy tall inside. I used real rough cut 2x6 rafters 16in OC. The gambrel truss runs the 19ft width.

Way overkill...I did 2x4 on 16" centers up in the great white north here and it was more than necessary.

 

[T_R]

2x4 rafters should never be in snow country. 24in OC should never be in snow country.
Adding the 2x6 beams should help quite a bit. Also add collar ties.
I would make the 2x6 beam out of two 2x6 with 1/2in plywood in between. 2x6 is kind of small to run 10ft, even if you double it up. With all this wood your adding trying to fix a probem you could just built it correctly.

I built a 13x19ft shed with a gambrel roof. The second story is 7fy tall inside. I used real rough cut 2x6 rafters 16in OC. The gambrel truss runs the 19ft width.

If you look at the span tables, it's 7-8' or so allowable span depending on species and grade for typical SPF 2x4 24 OC. This is assuming a properly framing of course. So on a 10 or 12 foot wide building you are ok.

Real world most small buildings here in Maine I have seen have 2x4 rafters 24 OC and are not collapsing in the winter. Most of us have a roof rake and know how to use it as well.

But I do agree with you, the OP should take this down and frame it correctly, not throw lumber at it to fix framing errors.

In the end it's a shed, not living space and doesn't need to be built to code in most areas.

 

[matt_i]

The strength is in the triangle. I don't see an issue unless the connections at the bottom corners are weak. If they are I would cut reinforcement gussets from plywood and use construction adhesive followed by torx drive screws to beef it up.

The 12' span could be an issue if attempting to store a lot of things in the attic or hang a lot from the bottom chord, because now instead of basic tension due to the roof load its now being stressed in bending.

Most sheds are slightly underbuilt compared to other structures you live in, its sort of a cost-benefit type thing and if it doesn't work then nobody's life span or life's savings is typically compromised.

 

[RWorth]

the only thing I don't like is the osb overhanging the rafters on the gable end. cut osb off flush with the last rafter.

 

[NUTTSGT]

can you show more pictures?
I'm thinking(from what I can see ) that the roof structure is not framed very well for snow loads. looks like very little to keep them from "flattening & pushing out" if that makes any sense
purely constructive criticism, not poking a jab at anyone

I'd like to see more pictures as well. Where you have the rafters sitting on the walls, how are they attached ?

 

[sooperdoosher]

I did not notch them (birdsmouth) because I have them tied to 2x4's that go across the span (so they can't "flatten"). I thought that would hold them - do you disagree? Thanks again for your advice

 

[sooperdoosher]

I've added a couple more photos - not much more shown (sorry). I tied the rafters with a 2x4 to run across the span (12 feet - also using them to make a loft for light storage)

 

[sooperdoosher]

More photos - thanks again to all for the help

 

[sooperdoosher]

If you look at the span tables, it's 7-8' or so allowable span depending on species and grade for typical SPF 2x4 24 OC. This is assuming a properly framing of course. So on a 10 or 12 foot wide building you are ok.

Real world most small buildings here in Maine I have seen have 2x4 rafters 24 OC and are not collapsing in the winter. Most of us have a roof rake and know how to use it as well.

But I do agree with you, the OP should take this down and frame it correctly, not throw lumber at it to fix framing errors.

In the end it's a shed, not living space and doesn't need to be built to code in most areas.

I appreciate your opinion, yet am quite sure I can add beams as suggested in much less time and expense than ripping the roof off and starting over. Can you comment on the beam idea? Or provide an alternate idea to fix?

 

[T_R]

Well, it's not framed correctly. Probably not what you want to hear.

The right way to do it is take the osb off and reframe it. Either cut rafters correctly and add a ridge beam with posts on the end or make trusses. Right now the way you have it framed with the rafters just sitting on the top plate, the only thing keeping the roof from pushing out is the nails into the top plate.

Is it going to fall down? Maybe, maybe not. If you don't want to take it down and redo it, maybe add some hurricane ties to each rafter where it meets the top plate. You are also going to have to do something with the way the last rafters are on the gable ends. They are unsupported as is the overhang.

In the end it's just a shed, do what you think is best.

 

[sooperdoosher]

T_R - I have the 2x4x12' tied from one top plate connection to the other (not just nails into the top plate to hold it)

 

[sooperdoosher]

The strength is in the triangle. I don't see an issue unless the connections at the bottom corners are weak. If they are I would cut reinforcement gussets from plywood and use construction adhesive followed by torx drive screws to beef it up.

The 12' span could be an issue if attempting to store a lot of things in the attic or hang a lot from the bottom chord, because now instead of basic tension due to the roof load its now being stressed in bending.

Most sheds are slightly underbuilt compared to other structures you live in, its sort of a cost-benefit type thing and if it doesn't work then nobody's life span or life's savings is typically compromised.

Matt - Thanks! I understand your response and will strengthen the connections at the top plates with gussets as you recommend. This makes sense! I'll also add strength to the chords, depending on storage load. Great stuff

 

[D45]

It's a shed, not a dwelling......don't over think it

 

[zak77]

Yeah, a few issues here but as everyone's said, it's only a shed. The 2x4's tying the top plates together will prevent any spreading of the roof structure but if you want added insurance you can always add a couple collar ties. If you had a ridge beam i would've suggested making it a structural ridge and that would solve that issue. But some better gussets or collar ties should keep it together just fine. Live and learn.

 

[lakeroadster]

Perhaps I missed it in a previous post but what will you be using for roofing material? If you will be using steel and not shingles, with such a steep pitch, it will shed the snow.

Good advice from Zak.. add collar ties.