This is an attempt to attach 2 photos of a beveled blind valley “sleeper” for a 12/12 pitch roof ( in a model). The bevel on the sleeper is 30º
You can find this bevel, by doubling the backing bevel on the hip, and subtracting the result from 90º. The backing bevel on a 12/12 regular hip is 30º, so, the circular saw bevel for the sleeper is
90º – (2x 30º) = 90º – 60º = 30º
If 2 different roof pitches are involved, add the 2 backing bevels on the irregular hip, and subtract from 90º, to get the circular saw bevel on the sleeper. For example, if the 2 roof pitches were 10/12 and 24/12, the 2 backing bevels on the irregular hip would be 55.65º and 14.25º. Add these and subtract from 90º to get the circular saw bevel on the sleeper.
90º – ( 55.65º + 14.25º) = 90º – 69.9º = 20.1º, or 20º, in practice.
Blind valley sleepers are seldom beveled, but if you want to know how to do it, that’s the skinny.
Edited 1/4/2003 6:11:02 PM ET by Ken Drake
Replies
The roof I've just finished cutting is 8/12 side to side, and 6/12 front to back. Here's a few pictures of the rafters ready to go, including the beveled blind valley sleepers. A second 2x6 will be added to make the sleeper wider. The circular saw bevel is 48º for this particular roof combination.
I'd like to repeat, that blind valley sleepers are seldom beveled, even though it does make them somewhat easier to set, and the nailing is certainly better for the sheathing.
Also shown are 2 rather large, separate stacks of rafters.. One stack contains the skeleton of the roof, that is, all of the hips, valleys, ridge boards, and common rafters.
The other stack, nearer the garage, are all of the jack rafters, including the blind valley jacks.
House is about 7500 sq. feet, so as you see, lots of jacks.
I'll try to get more pictures after the crew nails all this stuff up.
Here a some pictures of a valley board we beveled today. You'll notice in a couple of the pics that there is a beveled board that is obviously incorrect. That would be the one that is beveled at the same angle as the rafter makes with the plate.
This is a 6-12 roof. The correctly beveled sleeper is 53° and the incorrectly beveled sleeper was cut at 26.5° with the board on edge. It is clear that the 26.5° bevel is incorrect and nowhere close to what it should be.
Hi Tim,
That's correct.
The bevel on a hip in a regular 6/12 roof is 18.43º. So applying the formula that I suggested in my first post, the backing bevel would be
90º - ( 2 x 18.43º ) = 90º - 37º = 53º, as you have well demonstated.
Here are some photos of a blind valley from the last roof that we just completed. Normally, I wouldn't take the time to bevel the blind valley sleeper(s), but I did in this case to demonstrate how to bevel a sleeper, if you wished to.
The existing vaulted roof pitch is 8/12, and the roof that lays on top of it is 6/12. For this roof pitch combination, the backing bevels on an irregular hip would be 15.56º on the 6/12 side, and 26.34º on the 8/12 side.
To find the circular saw bevel for the blind valley sleeper, add the 2 backing bevels, and subtract from 90º
Circular Saw Bevel = 90º - ( 15.56º + 26.34º ) = 90º - 41.9º = 48.1º,
or, in practice, 48º.
Notice that, in the photos, the plate height of the 8/12 roof was higher than the 6/12 roof, so as the blind valley hits the plate line at the bottom near the fascia, a second blind valley is created for the 8/12 roof to lie on the 6/12 roof. The bevel for both blind valleys is the same however, 48º. In other words, the bevel on the blind valley sleeper is not affected by interchanging the roof pitches.
If you'd like to learn more about Chippy, and the Scotch, stop over at the JLC Forum, and look for this same topic.
Ken,
This valley the bottom is lower then the valley jacks due to architects instructions.
Valley
Bay blocks.
Nice try Joe, but no cigar. Take Fusco's advice and save as jpeg next time.
I threw together a little model showing the birdblocks that Tim will be cutting at the irregular octagon hip. Here they are. I'm going to link them over to JLC so he can have a peek.
Ken,
This was a 7/12 and 4/12 combination valley 2 2x10's no bevel on the bottom. bottom hung down lower then the bottom of the valley rafters.
These pictures aren'tr that good because there only taken from the top.
Edited 1/30/2003 5:37:18 PM ET by Framer
Trying again KEN.
Picture First House.
Tim,
I'll try this. If this doesn't work I'm going to Knock myself out.
Roof framing 1987.
Framer,
This might look a bit better. You know what I say about those crooked roofs. . . ;-)
Joe,
Can you do that for this one too.? xxxxxxxooooooooo
Whatdoya think I got time to keep fixin' the pictures of the crooked roofs. Pat said it was crooked too. . . . ;-)
This framing was done in 1987.
Octagon Roof.
I shot a short video with my digital camera today. The guy on the beam is Jason and the driver is Dave. I thought you might find this funny.
We had a 3 1/2" x 11 7/8" x 24' LVL and the only way we could lift it with the forklift was to drive it straight in. Believe it or not, but it worked really well.
I'm just learning alot of the mysteries of roof framing, but what do you mean when you say "backing bevels" With a valley rafter I know there's the plumb cut or ridge cut and the seat cut or birdsmouth. I also know valleys and hips have to be dropped or beveled to accomodate the roof sheathing. Is this what you are referring to? Please explain in lamens terms. I know, I know, I'm an idiot