Background: 2 x 6 stud wall construction
I am framing an utility building with 2 x 6 studs and have to build an 8-foot header. All of my reference material shows header size for 2×4 stud design. I could really use less depth to the header and should be able to accomplish this by making a solid header, 5.5″ x Depth. But I cannot find a reference table for this case. ( Most show two 2 x Depth boards with a lot of empty space in between.)
Can you direct me to a (preferably online) reference for this situation?
TIA
Replies
solid or not, the depth is calc'ed for span/load..you can have a hollow 2x6 header if there is NO load on it, but then, ya dont need a header huh?
Most codes want to see double jacks for an opening that wide..
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations.
My apologies, but I'm not sure I understand your reply.
I understand that the depth of the header is a function of the load it must carry, the span, and the chosen wood's characteristics. For example, a lot of tables are based on a 30 psf roof load, standard dead loads, etc. on a single-story wall and a common wood species. And the tables assume 2x4 walls so, say for example, you have a eight-foot wide window opening then you could use a built-up header made two 2 x 8 boards (eight-feet long) with a 7.5 inch x 8 foot x 1/2-inch thick piece of plywood or OSB spacer inbetween. This gives you a header or beam: eight-feet long, 7.5 inches deep and 3.5 inches wide - conveniently as wide as your 2x4 wall.
For a 2x6 wall, the references I have found say for the same case: use the same two 2x8 boards, place a 2x3 nominal piece inbetween at the bottom and optionally a 2x6 across the top; this looks somewhat like a box beam thus my use of the word "hollow". For a diagram, without the optional board, See page 6, Drawing C of
http://www.taunton.com/finehomebuilding/pdf/Framing%20Walls.pdf
In my case, I could use a header that is a bit less than the 7.5 inches (8" nominal) deep and, if I use a header that is solid wood, logic says it should be stronger. A beam 5.5 inches wide versus a beam 3.5 inches wide. Resource-conscious design favors the design shown at the above referenced site but I could use the extra inch or inch-and-a-half or two in depth reduction. Maybe such a table doesn't exist and I'll have to modify other building components or use a beam table/program.
Thanks for your reply - sorry if I wasn't exactly clear in my post.
keep it simple bud. Get your sizing out of your table. Either do Dino's foam sandwich or just go 2X+1/2"ply+2X+1/2" ply+2X=yer 5 1/2"
I like Mike Smiths plywood box beams..if an eng or inspecter greenlights it, that is exactly what I'd do..but hey, I ain't a framer (today)...lol
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations.
If I'm understanding this correctly, if the walls were 2x4, the required header would be two 2x8's with a spacer. But the walls are actually 2x6, so you have room for three pieces of two by with a spacer. You want to gain some height in the opening by going down to 2x6's for the header if it would be adequate.
The section modulus for 2x8's is 13.141 in^3, so two of them gives you 26.282. For 2x6's it's 7.563, and three of them would be 22.689
So, the three 2x6's would be not quite as strong, but close enough to be worth doing the calculations using the actual loads. If you see some nice pieces of select structural 2x6 you might want to set them aside for the header, in case the numbers work out OK.
-- J.S.
Here is one table that you can download, but it used engineered matter.
http://boise.bc.com/ewp/bldr_guide_eastern.jsp
The strength of the finished header is in its main horizontal members. All the spacers in between do is make up the wall thickness.
Save yourself all kinds of grief and skull sweat; use the header depth shown in the tables, but use three pieces instead of two, and add a piece of 1" Cladmate foam board into the sandwich to flesh it out to the thickness of your stud wall and create a thermal break (not sure if you'll be heating this utility building, but...). It will surpass the load requirements of the code by a fair margin.
You might also check the NBC (National Building Code of Canada); I think there are specs in there for 2x6 walls, as an awful lot of new construction here is done that way. Sorry I can't find that table in mine--too many missing pages got torn out to photocopy then lost over the years...time to shell out another 150$ for a new one, dang it....
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?