Sanity Check 12'x16' Cathedral Ceiling

Started by e12pilot, June 01, 2021, 06:04:58 PM

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e12pilot

Build: 12'x16' (w x l), on pier and beam foundation.
Wall height: 9' (2x6 w/double top plate)
Gable roof with 12:12 pitch
2 x 1.75"x14" LVL ridge beam 2.2E

There will be a loft on the south side for 6.5'  with beams running width wise (thinking 4x8 (12' span))

My question is on the gable wall framing and triple checking I have it correct. Will be partially balloon framing the gable walls and sending 3-2x6 studs from bottom plate to rake top plate. In addition will be strapping the other studs with 16 gauge straps on exterior and interior through sheathing (MSTA30s).  The site is protected from wind but I want to be really sure the gable ends are sturdy.

The roof will be sheathed with 5/8" CDX on 2x10 DF rafters. Following everything I can in the WFCM 2015 in terms of fastening schedules, etc.

Anything concerning/things that seem amiss in the plan?

Redoverfarm

Basicly looks good. Not sure of your intent on the loft but 6.5 is awfully small.  I would probably increase it to 1/2 of the building length.  If your intent is storage you might consider full length and place an exterior access door on one gable end.  Just a thought.


ChugiakTinkerer

Quote from: e12pilot on June 01, 2021, 06:04:58 PM
Build: 12'x16' (w x l), on pier and beam foundation.
Wall height: 9' (2x6 w/double top plate)
Gable roof with 12:12 pitch
2 x 1.75"x14" LVL ridge beam 2.2E

There will be a loft on the south side for 6.5'  with beams running width wise (thinking 4x8 (12' span))

My question is on the gable wall framing and triple checking I have it correct. Will be partially balloon framing the gable walls and sending 3-2x6 studs from bottom plate to rake top plate. In addition will be strapping the other studs with 16 gauge straps on exterior and interior through sheathing (MSTA30s).  The site is protected from wind but I want to be really sure the gable ends are sturdy.

The roof will be sheathed with 5/8" CDX on 2x10 DF rafters. Following everything I can in the WFCM 2015 in terms of fastening schedules, etc.

Anything concerning/things that seem amiss in the plan?

Welcome to the forum!

That's almost exactly the cabin I built as a guest cabin for our remote property: https://countryplans.com/smf/index.php?topic=14680.0
The only difference is I went with a full loft.  The head space in the loft is pretty limited, so consider lowering the floor/ceiling if you plan on needing to walk around much up there.

Of course, if there's a jurisdictional authority involved then they are the one to be asking the questions of.  If you're in doubt about the rigidity of the gable walls you could add more studs.  Do that after you get the walls up, as all that weight adds up.
My cabin build thread: Alaskan remote 16x28 1.5 story

Don_P

All studs should run unbroken between points of lateral support. Floor to floor or floor to roof. No amount of strapping or splicing is the same as an unbroken stick attached firmly at both ends.  The studs supporting the ridge should be built up 4 thick with a 1/2" spacer, 2 studs and ply under the lvl's one up alonside each side, especially on the end opposite the loft. It is a tall slender column and should be checked for buckling at design load. In this size building that should be plenty till you say you have a huge psf snow load.

e12pilot

Thanks for the insight, the snow load in the area is 25lb/sqft. The columns will be 4x6 DF with a stud on each side of the column.  There is a 32" door on the non-loft side that has the column terminating onto a double 2x12 header.  Balloon framing this seems a little tricky as I will have a hinge point here no matter what I do. Thinking of sending full height (to roof) 2x6's on either side of the doorway king studs. Thoughts?


Don_P

That's it but I'd double the full height kings on each side. Check the load on the header you may need to double the jacks as well to get sufficient bearing surface supporting the header without biting into it. (load/allowable compression perpendicular to grain= square inches of bearing surface req'd).

This is small, I'm used to working on larger stuff where I must check these things. I typically use my calcs to design, timbertoolbox.com, standard engineering calcs, but if the inspector is asking I can usually check beams and columns in WSDD, Wood Structural Design Data at awc.org. No matter the size it is always a good idea to check your load bearing elements.

e12pilot

Yep all the headers and trimmers went through Forte with the roof loads. Thank you for your help everyone!