What should the bearing be for a 9’3″ rough opening for a garage door?
I was thinking minimum of 3″, maybe 4.5″. The wall framing is 2×6 and the headers will be 1/2″ plywood sandwiched b y 3 2×12 s.
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Depends on what the header is carrying. Unless you're carrying a great deal, most likely a double cripple is all that's needed.
I know what Victoria's Secret is. The secret is that nobody older than 30 can fit into their stuff.
A 3 ply 2x12 header is probably worth bearing on 3 trimmers,
4 1/2". If possible you should run your cap plate for the full length of that wall also, tying the short walls and header together.
Depending on the width of your garage you may have over 5,000 lb bearing on the studs, considering the roof loads, and attic/storage, whatever. If your framing lumber is typical Hem-Fir, you'd have 800psi bearing; this may be reduced to 500 or less, depending on the load duration factors, moisture content during construction, etc ,etc so you can only bet on one stud only supporting about 4,000 lb. A three inch bearing is twice this. If you're looking for a rough rule of thumb that's what I'd use. Most importantly, tie it in with a continuous top plate or connectors like the post above said.
Darrell Hambley, PE
So is it carrying a twelve foot roof span in Florida or a fifteen foot second story machine shop in Wisconsin?
three or four studs on each end
Sorry for not providing complete info.
There will be a 2nd floor above the garage - a master suite.
Floor system for 2nd floor will be 14" Series 36 I joists from LP with a 22' 6" clear span.
The consensus seems to be 3 jack studs on each side for the garage header. Does the continious top plate really make that much difference when using a double top plate?
Thanks in advance for the reponses.
Scott
With a 2nd floor and roof load on this beam, I seriously doubt 2X12s will do the job.
Check into an engineered beam. Talk to someone familiar with your local codes and loadings.
Also - 14" I-joists are too shallow to span over 21', IMHO. I'd definitely recommend going with something deeper.
A fine is a tax for doing something wrong. A tax is a fine for doing something right.
Boss,
I questioned the need of an engineered wood beam for the opening to my local lumber yard.
They're a reputable firm with experienced personnel at the sales desk. Their opinion was that with a 9' span the benefits of an engineered beam would be minimal.
The 2nd floor joists will be perpendicular (bearing) to the header.
With regards to the 14" I joists, they will provide L/480 deflection requirements with typical dead & live loads. I think code is only L/240. I questioned this also and the saleman double checked before ordering. Maybe I should have gone to L/600?
This thread will explain why I said the 14" joists shouldn't span that far:
http://forums.taunton.com/n/mb/message.asp?webtag=tp-breaktime&msg=21010.1
BTW - What spacing are you using for the I-joists? If I had to guess, I'd say they told you that it would only work if you went 16" or 12" O.C.
.
As for the beam - People at lumberyards aren't trained to do engineering work. What they think doesn't impress me at all. I want to know for sure about beams, and don't take chances. What do they have to back up their opinion? Any facts or figures?
Based on my experience, it just doesn't sound right. But it might be O.K. depending on your roof loading situation. I'd wanna know for sure, not just trust someone's opinion.
Guns don't kill people. Postal workers do
I've heard a great deal of misinformation dispensed from lumber yards; Sometimes the salesperson is well-intentioned, sometimes just self-important. IMO they can be great resources for product, but I would never rely on them for critical information.
As others have pointed out, you're dealing with a critical load area and you need to know the characteristics of that load to properly support it.
A licensed engineer can probably calculate this out for you and provide some alternatives for construction and it shouldn't cost you an arm and a leg.
Off with their heads!!!
Which direction are the floor joists and rafters oriented with respect to the header? If they are parallel to the header the header load will be minimal. However, if they are perpendicular to the header the header loading will be maximized. Orientation of these load carrying components is critical to any evaluation of this question. We will also need the design loads for the second story floor, 20, 30,or 40 psf, and roof snow load, if any. This is not a problem to just pull one out of your butt. Educated guesstamates are fine sometimes but not in loading calculations.
There are many people here who can give you great advice, but they need all of the facts.
Lou,
The joists are perpendicular/bearing on the header. I'm located in Pittsburgh, Pa.
I had some of the concerns you mentioned and asked the sales rep. at the yard these questions.
I wanted to post on this message board since you guys have "working" knowledge and not just book smarts.
Scott
Still need rafter orientation and design load for the second floor, or at the very least, what the space will be used for. It would seem from my references that the snow load in Pittsburgh should be 30 psf. You might want to check with your building inspectors to verify this number.
A warning for you to consider. Around here, western NC, the building inspections dept. assumes that a owner/builder knows the right way to frame the structure, and that the issuance of a building permit is not an approval of any details shown on the permitted plans. It is only after the framing and sheathing are completed that they come out to do the structural inspection. That is not the time to find out that well intentioned advice was faulty or not in compliance with your local building code. We just changed codes and the allowed spans for everything that I have checked have been reduced. Obviously a response to the quality of the lumber available today.
Do you have a copy of your local building code? What is it? Those here who work with that code would be your most reliable source of info.
The trusses for the roof will be oriented the same (perpendicular to the header) as the I joists.
I just ran the beam for the heck of it, and came up with a 3 ply 2X12 #1 SYP being at about 150% of capacity.
So again, I would suggest looking at an engineered beam.
Lead me not into temptation. I can find it myself
I'm not going to say that 2 jacks will work, I'm just going to ask "isn't the rough opening for an overhead door usually the width of the door, so 9'-0"?
Around here, they're made 3" over. Then trim is added to bring the opening down to the actual size of the door opening. At least that's the only way I've ever seen it done.
Bachelors should be heavily taxed. It is not fair that some men should be happier than others. [Oscar Wilde]
Wivell, although I frame houses in the Southeast where snow loads aren't a factor, based on your posts, I am assuming your garage is a single car garage. Two trimmers per end would be fine. However, you state that not only do the joists bear on the header, but there is also a second story. I would go with at least three trimmers per side, maybe even four. I also question why the joists don't run parallel with the header, but that is another story. The 2x12 beam with layers of plywood sandwiched in between sounds sufficient, but again I would look into an LVL beam even for such a short span, again because of the extra weight bearing on it. As for why the full-length double plate, well that is a no brainer...my crew always lay out the two garage side walls with a corner on the garage door end, meaning the front garage wall (with the header) will tie into both solidly.
Capt,
The garage is a two car. I've attached a crude drawing as a pdf file so everyone has a better idea of the garage addition.