I am remodeling my two story house with a 4/12 gable roof. We placed a 34′ lvl beam under the ridge board and supported the ends in order to remove the ceiling joists.
I am in the process of creating rough openings for my windows. On the eave side, I want to make a 12′ opening for a picture window with two hung windows on the side. My question is; Would double 2×12’s with 1/2″ plywood filler suffice for a header? The walls are 2×4, 16″oc. (the rest of headers for all the windows are double 2x12s nailed under the top plates).
Thanks,
Mark
Replies
What, precisely, is the load of the ridge beam bearing on? And where are these windows relative to that load?
Dont know if this answers your question, but house is 30' x 30', 4/12 pitch, rafters are 2x10, 16"oc. The window header will be on the eave side.
Is this a clear 12 foot span?
Is this a clear 12 foot span or will you have studs separating the two double hung windows from teh picture window. If your window unit is mulled and the span a clear 12 foot span, I would not think I would worry a bit about a 2x12 header even in a gable wall. Any other wall and a 12 foot span, no way.
It is a clear 12' span (no separation by studs). Header will be on side (eaves) of house. I assume there is more load on the eave side due to the gable end having a support post on both sides.
Look into Glulams
You can google Glulam beams and load tables and or you can consult your supplier.
What is your snow load?
I have experience with a double 2x12 + 1/2 plywood garage door header with a 16 foot span. In this case the roof was a truss so the header carried one half of the 26 foot truss span or 13 feet. This header has about a ONE INCH sag in it. Not good if you have a window in there instead of a door. There were times when the garage probably had 40 or 50 pounds per sq ft snow load on it.
Now in your case you have a ridge beam (right?) and so with your 30 foot sturcture you have 7 feet of roof load vs my garage load or 13 feet.
So your beam would probably be safe. However, you will not find one load table or inspector to pass a doubled 2x12 in this application.
So, I would look into a glulam beam. They really are not that expensive, and two guys can handle a 13 foot (jacks studs add length). So, depending on the height of your walls you might be able to get a 15 tall beam in there.
Or if you put doubled up studs separating the double hungs from teh picture window it would become even easier to deal with.
I think your right. I was looking into LVL's, but they dont quite match the nominal sizes of 2x12's. I assume glulams can evenly match the size of 2x12's? (All the other windows are 2x12's nailed under the top plate). I wanted the windows to match the same height as the others.
Single or double top plate?
Are your other headers made , starting at the bottom, with a 2x4 on the flat, then teh 2x12, then a double top plate? If so you could do away with the 2 x 4 on the flat and one of the top plates, gaining 3 inches. So you would have room for a 14.25 inch Glulam (11 1/4 inch 2x12 plus the 3 inches gained by the removal of teh flat 2x4s). Of course you can't buy a 14.25 glulam, but you can easily buy a 15 inch glulam. That would make your header just 3/4 inch lower than other headers in the house! Who is going to see that?
And you can buy glulams at 3 1/8 wide or 3 1/2 inches to match teh width of 2x4s.
Gee, I suppose I should have saved time and just have said consult your supplier or engineer, but I am a nice and helpful guy.
Yep, very helpful, thanks. Headers are just double 2x12's with 1/2" plywood filler and nailed under a double 2x4 top plates.Headers I currently have in (6' and less) are supported by one jack stud on each side. House is in south central Texas, so not much snow load to worry about.
Texas ... ok
No snow load that is good. But still not sure if a 12 foot header would not sag over time even with just roof load.
I would google so tables for glulams and or go to a lumber yard and ask them to run the numbers.
Appreciate the advice, I believe thats the route I'm going.
Be sure to post what you learn or decide to do. Curious.
Good Luck.