Windows interrupt top gable wall plates
10man
| Posted in Construction Techniques on
Hello,
I run into this a lot; prints call for scissor trusses and large window units on gable end that extend above the plate level. The top windows are usually sloped to the cathedral ceiling angle, which is usually 1/2 the roof pitch in my experience. How do you folks frame these walls to tie them together so that the truss bearing walls can’t spread so easilly? I’ve tried it all kinds of ways, which work but are time consuming and involve angled lvl headers and metal strapping. Any ideas? Thanks.
Travis
Replies
Travis, we normally balloon frame those gable ends. Studs 12" OC with blocking where plywood breaks.
Jason Pharez Construction
Framing Contractor
"Studs 12" OC with blocking where plywood breaks."Jason,Studs 12" on center? I've never seen that before. Is that code for a cathedral truss gable?Joe Carola
at risk of butting in for Jason - could be he has a different reasopn, but a large window wall srtill needs to handle the wind loads on it which can be extremem there in hurricane country. That may be how his engineering plans handle the load. I've seen such walls designed with double studding on 16" or single on 12" before
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Sorry for being so late to reply Joe--this week has kicked my butt LOL!
I dunno if the OC spacing or balloon framing detail would change if scissor trusses were used--my detail comes from sticking the roof. But yes, we've now gone to balloon framing cathedral gable ends at 12" OC. I think it's mainly to bolster the rigidity of the wall (i.e., wind loads coming directly at the gable end). We also have to block the first two rafter bays at each sheathing break and block the first two joist bays (if the ceiling flattens off near the top).
If I ever meet up with y'all at a Fest, I'll bring some plans and pics of the stuff we do.Jason Pharez Construction
Framing Contractor
same as Jasason. The truss should be designed to prevent the spread you fear. maybe I misunderstand the Q
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Those trusses are cathedral. They wont spred the center of the walls, so I can't see how the walls would spread whether you use a top plate and just cut out where the header is or if you don't use a top plate at all like I do a lot of times and just frame the rake wall with gable studs and no plates.
Those trusses are cathedral. They wont spred the center of the walls
Set the bottom of the header at the rough opening height and then frame the angle of the window out of 2x4's.
This drawing has it both ways with the top plates framed on the left side and just gable studs on the right side.
Before I'll say that the trusses are already designed to prevent spread - are they a common scissor truss with blocking infilled for sheathing nailers?
Or are the just a gable truss with all webbing vertical - usually spaced for sheathing?
If your trusses are designed with the same webbing as the rest of the scissor trusses - you have nothing to worry about
Terry
Hello again, Thanks for all the quick replies. The trusses in this case are scissor trusses. I have had the most trouble when the job required stick framing, but in all cases I tend to overbuild. Helps me have fewer nights with the 'big eye' worrying about work. Your answers prove that I worry too much about this.10man
I balloon frame the wall as well, then nail the scissor truss to the inside of the wall for a drywall nailer and to prevent the spreading of exterior walls. My Mommy says I'm special.
Stilletto, Thanks for the tip.10man
I've got some pics of this somewhere I'll try to dig them up.
The window on the front right of the house is done this way it has a 90" height in a 9' wall plate height. Also has a samiched 2x12 header above it. Doesn't need it but the GC wants 2x12 headers everywhere including interior doors.
The window on the front lefthand side has the same height but was able to squeeze it in due to the garage studs being taller.
I'll get the interior pics tommorrow.My Mommy says I'm special.
Stilletto, Sounds like you GC like to overframe the way I do. I've switched to lvl's for headers and stair stringers a good while back. Hard to beat for stringers. Look forward to the interior pics. Thanks.10man
Here's the inside of the wall with the scissor truss nailed to the inside of it.My Mommy says I'm special.
Stilletto, Thanks for the shots; looks like a good way to do it. I've got one just started Friday that has the same sort of thing, so I think I'll use the "Stilletto Method" on it. Thanks again.10man
I've never seen one done like that before. But it's an interesting idea.
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Does it get your stamp of approval? :)My Mommy says I'm special.
I only have one minor concern.
If the truss is a regular truss, it may want to move with changes in humidity/moisture content. I'm not sure what would happen if the truss was nailed to the wall.
There are 10 kinds of people; those who can count in binary and those who can't.
Good point I'm not so sure it could move though, the wall is sheathed and the roof is sheathed where the balloon top plate stops. The truss being nailed off at each stud 16" OC on a 6/12 run.
That truss would have to move a ton to get that wall to budge. It's a gable truss, not sure if that makes a difference with the extra 2x4's in it.
I haven't had a problem with one "yet." Hopefully never will. My Mommy says I'm special.
weve done it where we'll build the wally and use the truss for a nailer, we'll also drop the top plates 3/12 for blocking, or 5 1/2 if we need the ventilation though the soffits. If I'ts a big overhang we'll use the truss for drywall backstop along the girder truss, cantilevering back two feet. If the trusses are not available. We will build the wall with double kingstuds shooting out the top of the wall. Header the window and all. Leaving everything outside of the king studs at reg wall height. It's not as good as a full one peice wall but it's pretty strong, I'd say on a small wall just as strong. when the truss comes nail it on and fill it in.
That's how I've always done in too Stilletto. It works great. It's fast. It's accurate. It's easy. What's not to like?
Many times, we'll drag the truss over and scribe it to the deck, then frame to wall to the lines without a top plate. The plywood and overhang ties everything together on the outside and the truss ties everything together in the inside.
Sometimes top plates are overated.
blue
Well at least I'm not the only one doing it. I like doing it this way, like you said its quick, fast, and accutate. It also saves me the time of coming inside and planing through the bottom chords of the rest of the trusses for drywall nailers.My Mommy says I'm special.