I thought it might be informative to show how my truss supplier details members when dealing with a valley and large overhangs.
This pic shows how the large 40.5″ overhang and 13.5″ heelstand is done with the common trusses, and how “clipped tail” trusses are required at the valley. Building size and truss layout determined that trusses meet in valleys without their tails coming together. You can see that common trusses would not be able to be cut to work at valleys, and that the clipped tail trusses have heel blocks at the bearing.
The plan view shows that the clipped tails are just wild of the valley line, to allow onsite beveled miters to be made to fit to the little hand-cut valley member that will tie everything together.
By doing the in-shop truss fab this way, we facilitate quick and easy field erection.
Replies
Your continued commentary on truss detailing is very valuable. I rarely use them but do occasionally, and will ask for some of your details next time. You're a formidable Sketchup artist at this point too. Hopefully your elbows don't ache too much.
Your common trusses don't have a bearing point at the heel. :)
The truss packages I get would have a girder on the big side and I would have to hanger the small ones off that. Then I would sheet the small side and hand cut the valley on top of the sheeting.
And I don't think I have even seen someone compound mitre a rafter tail in a valley situation like that. Does the truss package come with matching wood filler? :)
Your common trusses don't have a bearing point at the heel. :)
The pic is not representational. Actual trusses come with a web member in place above the bearing, not always vertical.
The truss packages I get would have a girder on the big side and I would have to hanger the small ones off that. Then I would sheet the small side and hand cut the valley on top of the sheeting.
Too much work for me . . . all those hangers, etc.
And I don't think I have even seen someone compound mitre a rafter tail in a valley situation like that. Does the truss package come with matching wood filler?
Cut them in place. Snap the valley-cut lines on the wild tails, plumb down the long side with a torpedo level, then whack them with a wormdrive set at 45. Spike in the pre-cut valley. Viola.
Wood filler? That the stuff you put in a bag and sniff? ;-)
I am just giving you a hard time Gene, the pictures are very good.
Have you had good luck with the premade valleys trusses like that? When I hand cut the valleys it gives me a little play room if something on site doesn't match the picture.
There are no valley trusses. All have the common pitch. The pic is probably misleading. We are only dealing with the tail situation here. Our little valley pieces reach from the inside face of the subfascia to the first or second inboard truss plane.
The low roof is sheeted enough to provide bearing for the lay-on valleys and overframed rafters.
I was mislead by the picture if thats the case. At any rate good drawing.
>> There are no valley trusses. << Just as an FYI, around here they are called "Valley Sets". When working with a truss manufacturer, I have the option to order valley sets - or not. Depends on the economics of stuff like the cost of the material and the deal I have with the framer; I expect slightly reduced labor costs and slightly quicker erection time time when I provide valley sets.
As far as your pics are concerned I think maybe one of the main issues is that your overhang is wider than the spacing of your trusses, which I assume is 24" O.C. Maybe somewhat common where you live, but I'd venture a guess that generally it's pretty uncommon. Maybe more common in snow country? Either way, in situations like that I'm more concerned about having the fascia heights come out right between 2 intersecting roofs and specifically if the 2 roofs are different pitches.
By doing the in-shop truss fab this way, we facilitate quick and easy field erection.
I guess roof framing makes you happy too, huh? ;)
By doing the in-shop truss fab this way, we facilitate quick and easy field erection
We'd facillitate quick and easy field erection too. We'd stub the 13.5" over hang, then scap our layon over it. Of course, we've never worked with exposed tails. All our overhangs are closed and the subframing is all buried in the soffit system. There is no need for "mitred" tail ends. Mitred tail ends falls into the category of "just because I can, doesn't mean I will".
blue
Ps Have fun mitreing yours!
Ditto blue! <!----><!----><!---->
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(Real valley in the overhang? What’s that for?)<!----><!---->
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He's not showing trusses that would look good with exposed tails or with raked soffit either. (funky flat cords into soffit area?)<!----><!---->
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In fact...<!----><!---->
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I'm not sure what he's showing here, except some good sketch-up skills.<!----><!---->
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Show-off! Lol<!----><!---->
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edit, font
Edited 11/15/2006 10:51 pm ET by MrJalapeno
Thank you for opening my eyes on this valley situation. I feel like the blind man that has had a miraculous cure, and now can see!
Since you are a regular here, you know from my past posts and pics that I framed this place once. I am now using SU as a planning tool (and it is fun, too) for preparing to build another copy of the house. I lost all my files from before, and this is giving me a chance to rethink the details.
The first time we framed it, we had our first valley experience with trusses. I had done hips . . . my partner had done no truss work at all. Neither my pard nor me knew what to do, and we had no old seasoned pros on site to offer advice. I dreamed up that detail shown in the earlier pics in this post, and we valleyed it up a little past the 42" overhang, and did a lay-on with 2x8 rafters above. Worked OK, we got the valley straight, no big deal. The house has three valleys.
I now can see that we can run one way long (full tails) right into the wall, have the others all stub-cut the same, and do the lay-on right from the valley bottom on up. Easier! The soffit is fully boxed in below. No tails are visible.
BTW, we used a 1x10 as the lay-on valley "plate," without beveled ripped edge, nailed on at the correct offset from the valley chalkline to pick up the layover and give us the line for our stick rafter ends. We did not bevel cut our edges of the 5/8 OSB deck coming into the valleys. OK with you, or should we be beveling?
Overall, for a couple of geriatric dabblers and some kids to help when there was a lot of muscle work to do, we did OK. My hard costs were far less than the bid I got from a pro framer.
Now, some more advice, please. Do you see anything you would do to simplify this eyebrow-roof porch frame?
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And finally, how would you detail the header and post arrangement at a corner like this? 2x6 wallframe, windows come tight to the corner with a 4x4 corner post, and the steel beam coming into the corner on the outside generating a sizeable reaction load with its bolted-on flange up against the header.
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Remember, it is a 3.5 x 3.5 corner post in a 5.5 thick wall . . . no opportunities for jackstuds at the corner, and that steel is bringing about a 6000 lb downward reaction load at the point it is bolted to the header through its flange.
Edited 11/16/2006 9:07 am ET by Gene_Davis
You are welcome for the eyeopener Gene.
Your first post of the valley is very easy to do with trusses. The first few trusses on the 13" overhang are stubbed. The longer 4' overhang goes all the way to the wall. We typically nail a "nailer" to the wall and run the plywood in full to the wall. Then, we lay a valley board. Your 1/10 is overkill because the main consideration is giving the rafters full bearing. In this case, since the rafter are small (we would use 2x4 scabs) we would only need a 1x6. We would NOT bevel the valley board. That is overkill. I have done it in some circumstances, mainly for fun, just to learn how to do it, but in the grand scheme of things, it is not necessary for a 5' valley layon!
Your porch situation looks like a sensible framing plan. My objection would be that the trusses would have to be precisely located to properly create the arch. When it comes to trusses, I don't like to count on precision. To facilitate that arched ceiling, I'd probably ask the truss company to raise the entire ceiling frame up a couple of inches to stay out of my finished space. I'd then rely on my own blocking to drop the finished framing to it's desired level. I find it easier to create my own plane, rather than to tweak their "out of alignment" plane.
The situation on top of the porch looks okay too. I'd sheath the top of the trusses, then lay on the shed rafters over the decking. Your particular situation would be a walk in the park for an old eyeballing hack like me. I'd string a straight level line as low as I could near the bottom and eyeball every bottom cut. After my first few misses, I'd have a pretty good grasp of the angles needed even though each one would change. My 16" or 24" layout would vary slightly as I adjusted my cuts and the rafters got a bit short, but in the end, I wouldn't even blink as I covered it up with 8' ply. I would spend zero moinutes trying to figure the cuts with a framing square or CM. That top roof layon would be about an hours work for me or Frank or half a dozen other guys that I have worked with.
Your beam poses a small challenge but the solution is also quite easy because your heels are so high. I'd raise that entire beam straight up and set it on the top plate. This might cause some engineering changes to the trusses that it carries but I don't think the challenges are insurmountable. The ceiling framing would be suspended from the beam rather than setting on it. If I needed the beam for aesthetic purposes, I'd frame a false beam under the steel beam.
Post a larger view of the beam situation. I need to see the overhang in conjunction with the steel.
blue