Shed dormer on 20x30 1.5 story question.

[mwhutch]

We have switched plans to the 20x30 1.5 story, and are wondering if it would be possible to do a 10' wide shed dormer on one side? We plan to use 12' walls to have about a 3' knee wall upstairs and have a full upstairs(if this is possible). We would like to do site built trusses from 2x6 material with the 12:12 pitch for the rest of the roof. Is 10 feet to much without a ridge beam? Thank you all so much, we will really appreciate all of the advice you can give!

ps. the bathroom in the plan is what we would like to make the shed roof.

[Don_P]

With that firmly connected to the floor, not a kneewall, a SE about took my head off. Personally I'd probably get an lvl ridgebeam and ask the supplier to have their engineer check it.

[mgramann]

I'm sure it is possible with trusses, but I would suspect you would need to get an engineer involved.  We have a full second floor on our build, along with 4 9ft dormers(gable)  At the ends of the dormers, they doubled up the trusses for strength.  Where I was, site built trusses were a no-go, but our supplier does the engineering for free if you buy their trusses.

[mwhutch]

Would it be better/easier if we made it 8feet instead of 10? Also could we use 16' studs and balloon frame the whole dormer wall? I guess I just worry that it would be more difficult and costly to use rafters and a ridge beam over site built trusses. Any one have experience with both?

[Don_P]

Who's engineering the site built trusses? Why not build 5-8' walls on the second floor deck and stick frame it correctly or use engineered factory trusses or a ridgebeam or, if that bathroom doorway wall or the two stair walls perpendicular to the ridge carry load down to the foundation it could support the top end of the roof.

[mwhutch]

We were going to build the trusses shown in the plans just to avoid a crane rental. It will just be the two of us for most of the build, and we are trying to keep the costs down. We have a pretty good structural engineer at our local lumber yard, and I'm sure he can steer us in the right direction for our specific location. Thanks for the help we really do appreciate it. We wouldn't be able to do this if it weren't for you all!

[Don_P]

I doubt I'd use a crane for any of the options I just described. It sounds like an opportunity here, see if he'll review the entire plan and stamp it for a specified snow and wind load in exchange for supplying the materials.