Trying to calculate how much of a knee wall I'll need for a building that is 32' wide with a 5/12 roof. I want to be able to walk in the center of the loft and I'm 6ft tall.
The from the first floor deck to the bottom of the 2x6 loft truss will be 8'
Any knee wall calculators out there?
The easiest way I've found to do that kind of planning is to get some graph paper and draw it out to scale----I know there are ways to calculate it with formulas but, visual aids work better for me.
Looks like you will be right about 6' without a knee wall. Could use 9' walls for a bit more room.
(https://i24.photobucket.com/albums/c42/bdubyah/Untitled.png)
Total width = 32 feet
Half-width = 16 feet
Rise = 5
Run = 12
Roof Height at center of building (above top of wall) = 16*5/12=6.667 feet = 6 feet 8 inches, or what wendigo said.... You should probably subtract the thickness of whatever you will have as ceiling material.
I'm like rw when it comes to figuring things out; paper and pencil. Our entire cabin was drawn out on vellum before construction was begun.
Print your own graph paper from a menu of types...
http://www.printfreegraphpaper.com/
The rafters interior line will probably spring from near the interior wall face instead of the line being calculated above. Do the math from a width of 31'1".
The loft trusses will probably have more than a 2x6 bottom chord unless there are a couple of load bearing walls below. But, if it is truly an attic truss, have them built cantilevered springing the top chord from the eaves instead of the walls, this will buy you more headroom.
I priced out the cost for a bonus room type truss with a 4' heel for a 24' wide universal. (I plan on using a 10/12 pitch roof)
I compared it to buying the 2 rafters, collar ties, I-joist and the material to make the stem wall. I was vary suprised as it was only about $10 or $15 more for each 2' of building length.
After you figure the cost of engineering to get the stick built attic approved I think it might even be cheaper.
My local truss company here in Boise will do all the engineering for the business. And I think it will be easier to get the trusses approved by the inspector.
However your bonus room will be 6' narrower. (3' on each side)
I needed the heel to get the side wall up to make the bonus room more usable. The heel did not add all that much to the price.
The truss company will give you a print out of the truss
(I got mine at 1/4" scale) Makes it easier to plan the house
I think it would be worth looking into in your case also.
Thank you guys so much for the help. Great info.