Opened a wall today and got a surprise. What size header would you install in this wall?
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
Source control, ventilation, and filtration are the keys to healthy indoor air quality. Dehumidification is important too.
Featured Video
Video: Build a Fireplace, Brick by BrickHighlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
near as I can tell, you have left out the most important piece of info - what live loads required there?
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
My bad... no snow load... been living 20 years in places without it so I forget some of y'all get snowed on.
A doubled 2x6 should do it then, but since you have the room in a 2x6 wall, I would use a tripled 2x6 and rest easy. Up here, I would need to go 3 - 2x8 or resort to LVL material
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
What kind of material are you using for the header?
It can be up to 5-1/2" thick, and 8-1/2" tall without removing the lower top plate.... add 1-1/2" if you remove that plate. Could be sawn lumber, PSL, glu-lam, whatever you think will work. I posted the question because I got two very different answers from two very qualified people.
Either a hollow box of 3/4in ply and 2x6 T&b, or two TJI's side by side. Spheramid Enterprises Architectural Woodworks
"We adore chaos, because we love to restore order"
Mauriets Chavailier Escher
My code book says 2 ply 2x6 assuming structural sheathing is used, 2x8 if not. That's using snow load data for Victoria, BC, which should apply for the San Juans. May as well bump it up to 3 ply while you're at it, but you will have plenty of clearance.Lignum est bonum.
I would use a 4x10, furred out to wall thickness.
"I got two very different answers from two very qualified people."
What were those answers? I'm kinda curious.
With no snow, you have very little load there. I figure a couple of 2X8s would be fine, unless your local codes require some heavy live load for some reason.
He who laughs last, thinks slowest.
2 - 2 x 8 #2 Southern Yelow Pine (or equal) / solid plywood between (flitch) with two cripple studs under each end / standard application for this header in my company no call backs because of sagging of insufficient support of load
2 x 6 wold probably work but very little savings especially when considering potential problems / the 2 x 8 s would provide great insurance against problems
otherwise....ask an engineer
"otherwise....ask an engineer "you are becoming a real asset here at BT tex, and I see you already have our standard respoince down pat, LOLTypically we wouldn't even begin to hazard an answer to this sort of Q except for three tihngs:david is a professional, through and through, so we know the answer won't be taken out of context or misappliedhe provided pretty thorough info in the sketchthis is an easy one
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I appreciate your appreciation. I guess us carpenter / builders are engineers by experience. I have taken problems to engineers and had them ask me what I would do...then they draw up my idea and stamp it. It is the stamp that makes it work.
Check out my ugly mug and a few of our projects at http://www.brotherscustomworks.com .
The site gets neglected and there are new homes we have built that need to be in a picture gallery. Comments (negative or positive) are apprecaited.
I look forward to lots of fun in Breaktime. I am also in Splash...a forum of architects / buildng designers / builders and engineers that use Softplan.....a CAD program specifically geared toward the residential market and design.
I have found these forums can be addictive, but it is nice to share with fellow carpenter / builder / contractors. I need to pull myself away right now and get to work.
Later.
That seems to be a dead link - for me anywayI've been a member of Splash since about its beginning. Read to learn but don't post very often over there. SP user since V9. We have a lot in common. I focus on remo work, rather than new
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Ditto for me. http://www.brotherscustomworks.com brings up a generic web page for godaddy.com.
Sorry. I recently did a domain registaration change from registar .com to godaddy.com at my web builders suggestion. Something is not right. I will look into it and repost when it is fixed.
Let us know. I'd love to check out your site too.
Add it to your profile when you do, and fillin the rest of it too.
To get there, just click on you name here
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
The job is simple: remove three windows that are ganged together, and install a large sliding glass door under the existing header. The owner built the house himself 20 or 25 years ago and swore that the header over the three windows was 6X8 #1 DF. Ok, sounds good.
Naturally I open the wall to find three short chunks of 6x8, one over each window. Call the owner, tell him my policy is that I will not recommend a header size and would like to get a calc done by my favorite PE. It will take less than 1/2 an hour. Owner says 'instead let me call my neighbor who is a very established builder'.
He calls me right back and the builder (who I know and respect greatly) has recommended we use a 6x10 or 6x12. OK, I already have a $3700 door unit on site and it will not fit under either one of those. Are you sure I can't call the engineer?
Anyway, I have a calc within two hours and it's for (2) 2x6 or (1) 4x6, which is exactly what the IRC table shows. This morning I put in a 6x8 (because it fills the space nicely) and we're good to go, 300% safety factor no extra charge. I was vaguely amused by the whole thing... but the guy with the beam calc software and the state-approved seal wins.
84" is about 7'
Perscriptive code gives the answer, but you asked "what would I use?"
You being a professional and me being one. That answer will require a check made out to me.
Shouldn't it be 2x6 for anything up to 72" and because this is 84 it should be 2X8? Dudley
Dudley ---You may be right. I expect you are, but I have no motivation to look in my code book.
Frankly, this is too basic a question to prompt guesses.
Figure it out like this:
This is a short span, so deflection is not an issue. Strength is the only item needed to be calculated.
M= Moment, a measure of strength.
L=Length of member.
w=Load per lineal foot on beam (simple span)
LL=Live load/psf, DL=Dead load/psf, TL=LL+DL/psf
M=wxL2/8 (that is L squared)
S= Section Modulus, the relationship between M and material strength where:
S=M/fb and for a rectangular section S=bd2/6 (d squared) where:
fb=fiber stress or strength of the material in bending depending on species and grade.
b= member width, d =member depth or height.
Example:
Assumming LL=10 psf, DL=15 psf(full ceiling fin, roofing etc.
TL=25 psf
w= 25 psf x 3.5'(1/2 span) +25x1.67'(overhang)=130 #/ft
L=7.04'
M=130x(7.04)2/8=805.4 #-ft (@ midspan)
Using Southern Pine, #1 grade, fb=1500psi (8" wide):
S=805 #-ft(12"/ft)/1500 (convert units to inches)=6.44 in3
Then use S=bd2/6 to determine size by setting either width or depth. As you can see, since d is sq, deeper bms are most efficent.
Say, we set width to 3" (2-2x) and solve for d:
d= (6S/b)1/2 (sq root)
d= (6x6.44/3")1/2 = 3.64"
So we need 2-2x6 (actual d=5.5") These could be spaced with blocking to flush with wall if desirable. You can use other values, but I would want some live load just in case someone walks on roof.
Im using Keybeam software here, and figuring a dead load of 20lbs, and a live load of 40lbs, just guessing on those, but I figured thats on the high end. The program says that a single ply of 1.75"x9.5" 2.0E LVL should be sufficient, but I would have someone with local knowledge check that.
Local requirements are 25# LL.
How would you compare the strength of the LVL you mention vs. 4x6 DF#2?
Welllllll lets see. Purely speculative here......but......
Live load @ 25#/sf, dead at 15#/sf = 40#/sf total.
Uniform load equals the 20" overhang + 1/2 of the clear span (42") = tot of 62" or +/- 5 ft.
5 lin ft @ 40 #/sf = total uniform load of 200#/running foot of beam for a 7' span.
Ye Olde secret book of wood structural design data says..... " ONE 2x8 (w/ a unit stress in extreme fiber bending (psi) of 1200) ie. decent quality, and a modulus of elasticity of 1042 will carry 214#/lin ft for a 7' span".
Throw in an extra 2 X 8 for insurance, and ply spacers for ghits and siggles, and you got yourself a good ole "sleep well at night header".
Or something like that.........