Trapezoid windows in a gable wall - Contractor Talk - Professional Construction and Remodeling Forum

bert0168 · 10-24-2009, 01:39 PM

I have a customer who wants some flanking trapezoid casement windows in an existing gable wall.

I am having trouble figuring out the header framing under the rafter. One window is taller than the other as they go up the rafter. These are on either side of a fireplace chimney.

I am not sure it can even be done on the short side (Andersons min short leg size for an operator is 3'4"). I am limited on space below the windows due to a set of bookshelves on either side of the fireplace (to be built). The height on the bookshelves is not set so they could be lowered a little.

I know rake walls carry less load than at the ridge and the exterior bearing wall (bottom of rafter). Do I have some options with doubling up the rafter to eliminate a horizontal header or is this going to be a no go due to the need for a horiz. header? My experience with trap. windows is 0. I've done 1/4 and 1/2 rounds before but this is the first for me with a limited space in a gable wall.

**Gus Dering** · 10-24-2009, 03:05 PM

Why do you feel you have to place the header level?

Why can't you place the header at the rafter elevation?

Aframe · 10-24-2009, 03:26 PM

Why do you need a horizontal header? Is it a trapezoid above a regular window? You can build out your rafter into a header. Just make sure you don't set the window so high you get into trouble with the rake trim.

2x10 headers are big for a 4'-6"opening, as you said the gable wall/rafter does not carry much of a load compared to the bearing walls.
If you did need a 2x10 or equivalent strength, swap out with some smaller LVL's.

(disclaimer "point loads-engineer-etc. you know the drill I hope)

**genecarp** · 10-24-2009, 03:31 PM

Quote:

Originally Posted by Gus Dering

Why do you feel you have to place the header level?

Why can't you place the header at the rafter elevation?

neolitic · 10-24-2009, 03:34 PM

The gable end wall is what we call
"non-load bearing."
What is carrying the other rafters
at that point?

**genecarp** · 10-24-2009, 03:38 PM

http://en.wikipedia.org/wiki/Trapezoid

Bert, are you talking about a casement window, with a fixed panel above that follows the roofline, sorry i am not getting it. GMOD

wallmaxx · 10-24-2009, 11:04 PM

Skip the headers entirely...multi-ply 2x10 rafters will do fine. Just double up the rafters above. Then you can just use studs and plates to furr down to your window top.

**Gus Dering** · 10-24-2009, 11:12 PM

Quote:

Originally Posted by wallmaxx

Skip the headers entirely...multi-ply 2x10 rafters will do fine. Just double up the rafters above. Then you can just use studs and plates to furr down to your window top.

Thats what I be talkin about.

There must be something we are not being told. I must give the OP the benefit of doubt until he comes back to clarify what's going on here.

wallmaxx · 10-24-2009, 11:16 PM

Like these....(or like Canadians say)...Like these ones.

I have (2) 2x12 rafters on top of the exterior plate. It's rock solid.

TimelessQuality · 10-24-2009, 11:40 PM

Quote:

Originally Posted by wallmaxx

Like these....(or like Canadians say)...Like these ones.

I have (2) 2x12 rafters on top of the exterior plate. It's rock solid.

That's beautiful Wallmax

the view's not bad either

wallmaxx · 10-25-2009, 01:01 AM

I re-read the post. Its in an existing wall. Maybe adding additional rafters would be too much going backwards.

Trace out where the windows go. Then offset 3 inches all the way around on the inside. Cut that all out to the inside edge of the outer wall sheathing.

Try and get some floor to top plate studs installed on either side of the window...may require all the sheetrock above the opening to be removed. The full length studs cut down on the wall being a bit harmonically shaky.

Take pics please.

Joe Carola · 10-25-2009, 06:13 AM

Quote:

Originally Posted by bert0168

I have a customer who wants some flanking trapezoid casement windows in an existing gable wall.

I am having trouble figuring out the header framing under the rafter. One window is taller than the other as they go up the rafter. These are on either side of a fireplace chimney.

I am not sure it can even be done on the short side (Andersons min short leg size for an operator is 3'4"). I am limited on space below the windows due to a set of bookshelves on either side of the fireplace (to be built). The height on the bookshelves is not set so they could be lowered a little.

I know rake walls carry less load than at the ridge and the exterior bearing wall (bottom of rafter). Do I have some options with doubling up the rafter to eliminate a horizontal header or is this going to be a no go due to the need for a horiz. header? My experience with trap. windows is 0. I've done 1/4 and 1/2 rounds before but this is the first for me with a limited space in a gable wall.

Get your short leg height and run the header the same angle as the rafter. It might not be a 2x10 because you can go higher and use a smaller header for that size opening and get a taller window. There's no need to run the header level in this situation. If you had a tall wall and were stacking windows with a trap on top, you can run horizontal headers in between. What you have here the small headers are always following the rafters.

I framed an addition 2 years again Little Silver and the trap windows were almost a little over 12'' and were 4-1/2" underneath the bottom of the rafters to allow trim. The Architect spec'd 3-1/2x11-7/8" lvl's as the last rafter. That stuck down 2-1/2" lower than the bottom of the 2x10 rafters and I added another 2" to get the height of the RO for the window.

bert0168 · 10-25-2009, 07:48 AM

I knew I could count on you guys!

I'll try to answer everyone's questions

First, yes, this is an existing wall BUT I would be stripping the drywall so I can have access to the entire thing rafter to plate.

I wasn't sure I could run angled headers. I was always under the assumption that they only worked horizontally. I did think the double rafter would be an option but I had never done it (or seen it done) myself. I'd probably add an LVL.

I do have pics but I am still in the estimating phase so they are only of the interior wall. I haven't started this job as I am still trying to get windows sized.

Gene, this is a trapezoid window that actually opens. Anderson will custom make these from 3'4" on the short leg up to 7'

on the long leg and from 2' to about 3' wide. I have no idea on the price yet but I am guessing it aint cheap

Aframe, you bet I am familiar with the points load, engineer line.

I plan on getting what I come up with stamped, I just wasn't coming up with anything when I posted.

So I need to decide on either the double rafter or a reduced size header that follows the roof line. I like the double rafter idea as it gives me more room for window (which is what the HO wants) but I've inserted rafters before and I know they can be a BIOTCH to get in place. At least I have some options now.

bert0168 · 10-25-2009, 08:00 AM

Quote:

Originally Posted by wallmaxx

I re-read the post. Its in an existing wall. Maybe adding additional rafters would be too much going backwards.

Trace out where the windows go. Then offset 3 inches all the way around on the inside. Cut that all out to the inside edge of the outer wall sheathing.

Try and get some floor to top plate studs installed on either side of the window...may require all the sheetrock above the opening to be removed. The full length studs cut down on the wall being a bit harmonically shaky.

Take pics please.

Are you saying I potentially (with proper approvals) can eliminate the headers and the multi ply rafter with full length studs on either side of the window?

I plan on stripping the drywall off entirely to allow access to all the framing so full length studs and several aren't a problem. I know gable ends aren't load bearing.

BTW, that is a killer view out that beautiful window (the framing is nice too)

**genecarp** · 10-25-2009, 08:06 AM

Quote:

Originally Posted by bert0168

Are you saying I potentially (with proper approvals) can eliminate the headers and the multi ply rafter with full length studs on either side of the window?

I plan on stripping the drywall off entirely to allow access to all the framing so full length studs and several aren't a problem. I know gable ends aren't load bearing.

BTW, that is a killer view out that beautiful window (the framing is nice too)

Not answering for wall, but i do believe that is the case, by running the studs up to the underside of the rafter you are reducing the span, i would go with 4 doubles, notched around the outside rafter. If you really wanted to go heavy duty, sheath the whole int wall with 1/2' CDX, THEN ROCK OVER THAT, GMOD

bert0168 · 10-25-2009, 08:11 AM

Gene, that's not a bad idea sheathing the interior with 1/2 ply since I am already ripping all the drywall. Would definitely make for a super strong wall and they could hang chit anywhere they wanted to.

**genecarp** · 10-25-2009, 08:16 AM

Quote:

Originally Posted by bert0168

Gene, that's not a bad idea sheathing the interior with 1/2 ply since I am already ripping all the drywall. Would definitely make for a super strong wall and they could hang chit anywhere they wanted to.

Sure you know it, but when you lay out the int sheathing, strap across all plates, i may create a bit more waste, but the concept is lost if the plwood does not strap the plates. GMOD