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header sizing??

Started by northernss454, October 25, 2009, 09:19:18 PM

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northernss454

Hi all, my shop I am building will have a 20 foot door, its on a supporting wall. Snow load is 240 psf. Can anyone tell me what size of header I need to put in. I got a friend to put it up while I was away, he used 4  2x10 spruce for header. I think its a bit light but just want to double check, as I don't want to criticize his work. I was away at work when it got built and am still away just want to check before tin goes on its easier to fix now compared to later.
Thanks

beenthere

Did your friend put it in to your specs?
What is above the header now? How far up to the plate that the rafters set on?

A little more info would help.  :)
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

DouginUtah

-Doug
When you hang around with good people, good things happen. -Darrell Waltrip

There is no need to say 'unleaded regular gas'. It's all unleaded. Just say 'regular gas'. It's not the 70s anymore. (At least that's what my wife tells me.)

---

northernss454

Hi, I might be wrong about snow-load,what happened was I originally had the door on the gable end and they sent 2 laminated 2x12.I changed my mind while he was building so he put the 2x12 over the supporting wall, and decided to add 4  2x10 on top of the 2x12.
Its a 12 foot door with 14 foot walls,so there isn't much room left to put another header. I was thinking of putting 3/4 inch plywood over the whole thing, not sure if that would help or not. Like I said again on the snow-load for some reason that number rings a bell, and being in northern Canada we do get a lot of snow, also have snow stops over the door.
Thanks again guys

beenthere

I think you have good cause for concern. If you could put a 24" truss in the header space above the doors, with some engineered design, I would do that.

Not sure how what you describe with the 2 2x12's and 4 2x10's are stacked up, but unless they are tied together so the shear forces are reduced, they may just be filling in the space and not taking much of the load.

Care to draw out a picture for us?

When you say laminated 2x12, are you talking the veneer laminated rimboard product?

Is the wall thickness above the door 4"?

I'll see if I can draw out what I think you are saying. Might not be right.  ::) ::)
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

northernss454

Yes he put up the 2 laminated beams, then after he looked at it he decided to put 4 separated 2x10 on top of the 2x12. So they are not joined together. I am debating on weather I should put a steel I beam on the inside it will be exposed but at least I will not have to worry.
Thanks


DouginUtah


I'm with beenthere--not sure how this is going together. The two 2x12s are four inches wide. Four 2x10s are eight inches wide--unless nominal (6"). Are the 2x10 just sitting on the 2x12s? If so they are doing nothing but adding to the load on the 2x12s.
-Doug
When you hang around with good people, good things happen. -Darrell Waltrip

There is no need to say 'unleaded regular gas'. It's all unleaded. Just say 'regular gas'. It's not the 70s anymore. (At least that's what my wife tells me.)

---

Left Coast Chris

Here is the needed info in order to size the header:

1)  You noted that the header is in a "supporting wall".  What is it supporting?  (need roof joist span, overhang, roofing materials to calculate dead load)

2)  Call your local jurisdiction and verify snow load.  Also ask if double snow load is required at overhangs to account for ice or other ice requirements.

3)  Will the door be supported by the header? (door track bolted to header -- or a roll up door supported by its own shaft mounted to the king studs).

There are several people that can help you.  We just need the info.   :P :) 
Home built cantilever head, 24 HP honda mill, Case 580D, MF 135 and one Squirel Dog Jack Russel Mix -- Crickett

northernss454

Hi all I will find out snow load today. Yes the 2x12 are laminated, and 4 inches wide. The 2x10 are 6" wide 1 1/2" each. The 2x10 are adding weight to the 2x12 as they are on top, but they are spanning full length and resting on the cripples so I am assuming they are helping not hurting. The door has a opening attached to cripples, so no weight on header. Roof span is 34 feet 4 foot centers no overhang, there is 5 rafters sitting on header. The roof is tin and will be insulated with blow in to a R50.
Thanks again, and yes now I am getting concerned.

northernss454

Hi again, my snow load is 40 psf. Thanks all, this has been on my mind all day long

Left Coast Chris

Hi Northern,   

The first step is to determine the load on the header.   Assuming there is no ridge beam running parallel to the header in the center of the building and the beams supported by the header are spanning 34', the load is approximately (10psf+40psf)X34'/2= 850#/foot.    That is a hefty load especially for a 20' span.     The 10psf is the dead load of the roof and the 40psf is the snow.

The two 2x12s do not come close to making the allowable loading for Southern Pine or Douglas Fir.   If fact, with no snow (only the 10# dead load) you would need a 6x12 and it would be at full capacity.     

Suggest getting a local engineer to check out your situation, verify the span of the roof joists and check them while he is at it.  Im not sure of your discription of the loading but if the load is 850# per foot (equivalant) then a Glulam 5.125"x19.5" grade24F-1.8E would be needed.

For everyone's safety you shoud not add the insulation since the existing 2-2x12's are likely to be over stressed.
Home built cantilever head, 24 HP honda mill, Case 580D, MF 135 and one Squirel Dog Jack Russel Mix -- Crickett

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