I am a novice homebuilder, attempting to build a 26'x46' garage. The homeowner wants the garage door opening to be 22' of open space, with no post in the middle -- completely open space. So, I need a 24' span header. What do I use to do this. Glu-lam is way too heavy for me and my partner to lift in place by ourselves, and we can't muster ten more guys to help us. So, do I buy LVL at a 24' span, or do I build my own box header? Cost is not a factor. Just need to know what to use to avoid a sag in the middle.

Without knowing what loads may be imposed on the header, it's impossible to comment precisely, but probably a double or triple VERY deep LVL would be necessary, or a piece of steel wide-flange section.

If your customer were my client, I would be trying to talk him or her out of a 22-foot door. Even 16-foot doors can give a lot of trouble. For reliability, a good-quality commercial door should be used, but it won't look very residential.

Is the header on the gable or eave end of the building. If it's on the gable then there is no need for Glu-lam or LVL. You also need to take into consideration the amount of shear-wall you will be left with if the opening is on the 26' span of the building. You will only be left with 24" on each side.

Get the LVL beam and get a crane rental and operator to help you set it. I think you could expect it to cost around $300-750 depending on rates in your area. Even a double 2x12 wouldn't cut it for that big a span.

The truss company you bought the rafters from will be able to answer that question, they have qualified engineers on staff to calculate these types of things. As for the 24" of sheer wall, there are code compliant alternatives for this, such as concrete embeded ties or running your garage header the entire width of the building

Just one other thing to keep in mind. Even if the header is taking no gravity load (if it's on the gable end), it is taking significant weak axis wind load. A 22' span is not joke for wood in strong axis bending, it's even worse for weak axis bending.

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Originally posted by structuraleng:
Just one other thing to keep in mind. Even if the header is taking no gravity load (if it's on the gable end), it is taking significant weak axis wind load. A 22' span is not joke for wood in strong axis bending, it's even worse for weak axis bending.

I completely agree. You need to have someone qualified to look at your plans.