Framing Plan on a 20x30 single

[rothbard]

Not sure if it'll be useful for anyone in the future to look at, but this is my own framing plan* for the long walls on the single story 20x30, modified a bit.  Studs are 16" o/c except as noted.  It is split into 3 10' sections for easier righting with one man. I'll try to post the other 2 walls as I get to it. 

Hatches on the diagram indicate a stud turned on side for a intersection channel that meets another wall.

*This is not engineering advice.  This is merely informational of what I planned for my own house.

[Don_P]

Look down, are studs over joists? (check that the toilet drain clears).  Look up, rafters, or if 24" oc, every other rafter, is over a stud. LONG laps of top plate splices. There will be a gap in the top plate at wall tees. Some like doubling the windowsill plate for more trim nailing. I use double 2x10's and foam for header space most places at the price of insulation. It is easier to insert those king/jack/header assemblies after the wall is up. If a stud is close to that zone I insert it later to provide room for the component. I lift an "empty" wall... or use equipment. To frame the rake wall I've lofted it out full size on the subfloor, mark and cut to the lines. I've also temporarily screwed a rafter over the wall line, screw several blocks to the underside and temp screwed the 1st top plate under those spacer blocks. Layout the bottom plate, plumb and scribe the studs and build it that way. On your tall studs think about their height x their spacing x ~20 lbs per square foot. Divide that in half. Your connection stud to plate and plate to roof diaphragm needs to be that or better, all along the wall, then plant that accumulated load into the corner as push or pull, strap around the wall corner to transfer.

Most of my career my wife was the crew. On one job we had a pair of relatively short but 17' tall sidewalls in a greatroom. For some reason I thought we could tip it up. As we walked forward it quickly became apparent that the wall was more likely to flip over our heads. We refer to that moment of realization as an ignosecond. Without equipment I set up some form of scaffold and build tall walls in place.

[rothbard]

Thanks Don.

I'll have to take note of the scaffold idea and do that for the long rake wall.  Don't want an ignosecond

I think I understood all you mentioned except the last part.

> plant that accumulated load into the corner as push or pull, strap around the wall corner to transfer.

 Can you expand to what part of the corners you strapped for the load transfer?  You mean like straps distributed top to bottom around the exterior of the corners?  Curious if you know of any photos that might help me understand it.

[Don_P]

On the raking balloon framed top plate to level eave wall top plate corner, you cannot overlap and connect the gable wall to the eave wall very well there. (As per prescriptive code requirement) A horizontal strap around the corner will recreate that connection between the wall facing the wind and its adjoining bracing wall. You will need some blocking in the tall wall to get good nailing for the strap,

The 1st pic shows the basic thinking of how wind load from one direction moves from the walls it hits through the flatter diaphragms and into the adjoining bracing walls down through braced foundation elements and to the ground. Obviously on the tall wall all you have is the main floor and the roof diaphragms transferring that gable wall load to the adjoining bracing eaves walls. The lateral load pumps both ways, those walls get sucked out too.

2nd pic, going down the rabbit hole. The codebook tall wall stud size table is pretty skimpy. There is a better, recognized, one. Both of those shots come from the WFCM, Wood Frame Construction Manual. Code referenced and free download from awc.org. in the pg 130 neighborhood is a series of good typical detail sketches. If the bending stress is exceeding... `1000psi, start paying close attention to the grade or step up. I think 2x6 will do you but I've had 2x8's several times on tall walls.

[rothbard]

Very interesting.

I had wondered how the gable end attached to the long walls when the top plate was angled!

Table here is super useful.  I can see now on the tall gable 2x6 16' max 16/oc" it is right on the ragged edge of doug fir stress limits once wind hits 110 mph.  I will definitely go in and change my spacing to 12" on that wall.

I'm getting a lateral parallel to ridge of ~100plf based on the table, or about 2000 lb across pf across the 20'.  Fortunately I have awhile yet to figure out how to strap that amount of force in.