20x30 1 1/2 vs 20x30 Single story.

Started by Bearmech, April 29, 2016, 12:33:55 PM

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Bearmech

Good afternoon. We recently purchased the 20x30 1 1/2 story plans and we have decided we don't need the loft. So, we plan to build the basic structure 20x36 and continue the gable ends an additional 12' on each end with an 8/12 pitch and add 10' full length shed roof porches on each side with a 3/12 pitch.
My thoughts are to build the 1 1/2 walls as per plan and set the shed porch rafter on the top plate of long walls and let in the ledger on the outside of the 2x6 walls to support the porch ceiling joists. I know this would require beams to continue the gable roof for the 12' porch on each end. We would use  a crawl space foundation on the main structure and a continuous footing with cmu piers at 4' on center for the outer porch foundation.
With ceiling joists at the 10' top plate to also serve as rafter ties and all else considered will a ridge board type roof be appropriate? and how does the rest of the plan sound?

John Raabe

#1
Let me describe what I think you are asking for... The enclosed basic heated core is 20x36. At each end of this core is an extension of the gable roof to cover a 20x12 open air porch. This completes the main roof which is a 60' long gable. You want 10' deep porches on either sides and maybe also on the gable end to tie together the porches and end rooms. These side porches would be at a lower pitch.

The suggested foundation is fine. I would not use the 1-1/2 story wall and roof connections, but do standard 2x6 wall framing to support 24"o/c roof trusses with a flat ceiling at 10' (the truss company may have other options for the ceiling shape). The 20' wide single story plans may be helpful as they have more details about trusses than the 1-1/2 story plans.

This gives you a large open indoor/covered porch space 20x60 with a 10' high ceiling. This space could support lots of tall windows.

There are a number of options for the lower pitch side porch roofs.

Try that out and see if the space works for you. It will involve getting local help for drawing this up but it is a nice simple structure.


None of us are as smart as all of us.


Bearmech

"Let me describe what I think you are asking for... The enclosed basic heated core is 20x36. At each end of this core is an extension of the gable roof to cover a 20x12 open air porch. This completes the main roof which is a 60' long gable. You want 10' deep porches on either sides and maybe also on the gable end to tie together the porches and end rooms. These side porches would be at a lower pitch."


Yes, and I was thinking 8' ceilings on all porches. What about the let in ledger for the side porch ceilings?
The plan is to add another 20x30 cabin on one end at a later date to create a dog trot.


Don_P

I like the 10' interior walls/ceiling joists topped by an 8/12 and doing the pitch break over that point. I wouldn't let in the porch ceiling ledger. There is little load... ~50 lbs/cj. I'd prefer to sheath the wall continuously and nail of timber screw a ledger to the studs through the sheathing then nail or hanger the cj's to the ledger.

John is thinking in the right direction though, truss it. They can make 20' 8/12's for the main and then wall mounted 3/12 mono pitch sheds for the porches. They'll probably span the ends with girder trusses up in the roof. I'd run it by the local truss shop.

Bearmech

Thanks. I'll ask the truss guys when I get there!