16' Garage Door Headers

[vegas paul]

Double garage doors, nominal 16' wide... I often see them on plans for detached garages. Given that the IRC is essentially intended to allow prescriptive design/building without engineering, how do you address the header span for a 16' garage door? Do you allow an engineered (LVL) or similar component, based on the spec. sheet for that beam? Or do you strictly enforce the IRC span tables (which don't address this)? I hate to require engineering on a 400-500 s.f. detatched garage.

Just wondering how you look at these in your neck of the woods...

 

[Min&Max]

Re: 16' Garage Door Headers

The vast majority are using engineered wood products for these. Do not require an engineer to sign off. Manufacturer provides span charts and installation instructions in manual. If anal retentive, their is more info for the asking.

 

[Uncle Bob]

Re: 16' Garage Door Headers

Paul,

I see no reason not to accept an engineered (LVL) (gluelam) or similar component, based on the manufacturer's spec. sheet for that beam. That's all I've seen over the past few years. It's well within my comfort zone.

Min&Max,

How did you find out my real name? Anal Retentive.

Uncle Bob

 

[vegas paul]

Re: 16' Garage Door Headers

Oh, I agree about using the engineered headers, per the mfg. instructions... maybe I confused the issue with my original question. What about using dimensional lumber (4 x ?, multiple 2 x ?, etc.) that aren't on the span tables of the IRC? Anybody allowing this without engineering? Even if it appears over-designed, do you allow it?

 

[mtlogcabin]

Re: 16' Garage Door Headers

We run the numbers thru StruCalc if it passes fine if not they have to resubmit. We DO NOT tell them what size is needed.

 

[Uncle Bob]

Re: 16' Garage Door Headers

"using dimensional lumber (4 x ?, multiple 2 x ?, etc.) that aren't on the span tables of the IRC"

Get an Engineer for about $150.00.

Absolutely, positively, unequivically, NO!

Uncle Bob

 

[cboboggs]

Re: 16' Garage Door Headers

We take the same approach as mtlogcabin. We run construction through a program either StruCalc or Plans Analyst. If it checks out fine if not they have to resubmit.

 

[conarb]

Re: 16' Garage Door Headers

It's not that simple, almost all garage door headers require portal design, and usually narrow portals integrated with the header, this always requires engineering, listen to your uncle.

 

[brudgers]

Re: 16' Garage Door Headers

It's not that simple, almost all garage door headers require portal design, and usually narrow portals integrated with the header, this always requires engineering, listen to your uncle.

In areas with significant lateral loads from sesmic or wind, yes.

In areas without such loads, it's not such an issue.

 

[Alias]

Re: 16' Garage Door Headers

Like UB and conarb, not without an engineers stamp. As brudgers pointed out, I'm in a high wind/seismic/volcanic area plus I'm in CA.

Luckily, the local contractors know this, it's just the DIY'er who is a potential problem.

Sue, lost on the frontier

 

[vegas paul]

Re: 16' Garage Door Headers

Well, Sue, the DIYers is exactly why I posed the original question. I'm all for helping homeowners that want to improve their homes and I try to guide them through the IRC when they want to do their own designs/plans. Since detached two-car garage/workshops are a common project around here, I see them a lot, and I see some VERY interesting design solutions - most of them noncompliant.

I often suggest LVLs or other engineered headers along with Hardy Walls or Simpson Strong Walls for lateral/shear on the open end. However, considering the cost of these vs. dimensional and sheet goods, usually the original design doesn''t include them.

Thanks for the opinions... I keep striving to help out the homeowners!

 

[mtlogcabin]

Re: 16' Garage Door Headers

The garage and other window and door openings are prescriptive see

FIGURE R602.10.6.2

ALTERNATE BRACED WALL PANEL ADJACENT TO A DOOR OR WINDOW OPENING

A minimum 3" X 11.25" net header size is required for opening from 6ft to a maximum 18 ft. That would take care of the wind and seismic shear loads. Correct?

A larger header may still required due to additional floor/roof loads.

 

[vegas paul]

Re: 16' Garage Door Headers

mt - As long as the walls adjacent to the door are 16" or wider, I've used exactly what you cited above - however, it seems that many want to maximize their openings (16' door) with a building that is limited by lot size, resulting in 12" in. or less by the doors! I get 18' wide garges submitted often. Won't work unless a strong wall is used.

2nd point - It is interesting that the header in figure R602.10.6.2 goes up to 18' in length, with "min. 3" X 11.25" , which means that it might have to be bigger, depending on the actual use. But the table R502.5(1) doesn't go to 18' so how does one determine how much greater than the minimum is required? (Assuming dimensional lumber is used, not LVL). I assume the 3 x 11.25 is based on the alternate braced wall panel working for lateral/shear, and is NOT based on the header supporting the load above. That's why it's minimum for as little as 6' wide and the same up to 18'.

 

[Uncle Bob]

Re: 16' Garage Door Headers

MtLogCabin,

"A minimum 3" X 11.25" net header size is required for opening from 6ft to a maximum 18 ft. That would take care of the wind and seismic shear loads. Correct?"

Does not state that header (6' to 18') can be "dimensional lumber"; only that the minimum net header size shall be 3" X ll.25".

Maximum length for a "dimensional lumber" header for roof and ceiling only; would require 4-2X12s and be limited to a 14' 1" span (TABLE R502.5(1); which would require a 6" wide wall; provided the building width was not more than 20'.

Now if they put double doors in; they could use double 2"x10"s (maximum span 8' 5"); with support in the center of the 16' foot opening; and your going to need every inch of that 20' building width. Requires braced walls to be minimum 16" wide each X 3 = 48" should allow two 8' openings (barely).

I think,

Uncle Bob

 

[mtlogcabin]

Re: 16' Garage Door Headers

UB I agree and Under StruCalc what you stated is good by 85% with a .198 deflection 46lbs snow 15 lb dead loads. That's why we use StruCalc to double check submitted design loads that are not prepared by an engineer.

 

[Uncle Bob]

Re: 16' Garage Door Headers

MtLogCabin,

Thanks, I don't know that stuff; so I have to either go by the codes or Engineered. Heck, at 65, I don't want to know that stuff.

It's good to know that some of ya'll learn stuff beyond the requirements of just knowing the codes.

Uncle Bob

 

[fatboy]

Re: 16' Garage Door Headers

We allow and check submitted engineered products, do not do design though. Seismic and winds are not an issue here.

 

[brudgers]

Re: 16' Garage Door Headers

UB I agree and Under StruCalc what you stated is good by 85% with a .198 deflection 46lbs snow 15 lb dead loads. That's why we use StruCalc to double check submitted design loads that are not prepared by an engineer.

From my time behind the counter, it's probably a good idea to spot check designs submitted by engineers as well.

The Braille method of plan review is not very reliable.

 

[Uncle Bob]

Re: 16' Garage Door Headers

Brudgers,

"From my time behind the counter, it's probably a good idea to spot check designs submitted by engineers as well."

I'm afraid that as an Inspector; I'm not qualified; nor should I be expected to be qualified to judge Engineered Designs (signed and sealed) that execeed the codes. In that case, I am required to be able to read the Engineer's plans; in order to insure that the construction is per plans.

"The Braille method of plan review is not very reliable."

As far as plans that are submitted that are within the "Design Criteria" of R301; I also don't consider using the code requirements, to review plans as "the blind method"; and I believe my answer to the original question reflects that.

Would be so kind as to show me what part of my answer that was wrong; or where I used the "Braile method of plan review"?

"A minimum 3" X 11.25" net header size is required for opening from 6ft to a maximum 18 ft. That would take care of the wind and seismic shear loads. Correct?"

Does not state that header (6' to 18') can be "dimensional lumber"; only that the minimum net header size shall be 3" X ll.25".

Maximum length for a "dimensional lumber" header for roof and ceiling only; would require 4-2X12s and be limited to a 14' 1" span (TABLE R502.5(1); which would require a 6" wide wall; provided the building width was not more than 20'.

Now if they put double doors in; they could use double 2"x10"s (maximum span 8' 5"); with support in the center of the 16' foot opening; and your going to need every inch of that 20' building width. Requires braced walls to be minimum 16" wide each X 3 = 48" should allow two 8' openings (barely)."

Thanks,

Uncle Bob

 

[JBI]

Re: 16' Garage Door Headers

U B - I don't think brudgers was suggesting you were wrong. I think he was just reinfircing that plans should always be checked, regardless of who prepared them. I agree with that 100%, some of the worst plans I've seen have come from engineers... WITH a seal/signature on them.

Simply looking for that seal/sig (or feeling for the raised seal... the 'braille' method) doesn't cut it.

That's twice in a week I've agreed with brudgers...







:lol:

 

[Uncle Bob]

Re: 16' Garage Door Headers

John,

I check your previous posts; and that's only once this week that you have answered for someone else, instead of letting them answer the question that was meant for them.

I also don't believe that my answer to the original question reflected my "Simply looking for that seal/sig (or feeling for the raised seal... the 'braille' method)".

Thanks,

Uncle Bob

 

[brudgers]

Re: 16' Garage Door Headers

Of course I was suggesting that even sealed plans should be spot checked.

There are plenty of engineers out there who will specify the minimum size explicity listed in the code rather than the size required by the loads.

Of course, garage door headers in the gable end don't support any roof or snow load, just the dead load of the wall above, and the minimum size may be acceptable (i'd have to run the calcs.).

And Table 502.5(1) lumps species together. (4)2x12 SP #2 will carry a 20' roof over a 16 foot opening with 30psf snow load.

See page 8: http://newstore.southernpine.com/images/ref207.pdf

With no snow load it will carry 24 feet of roof.

 

[brudgers]

Re: 16' Garage Door Headers

John,I check your previous posts; and that's only once this week that you have answered for someone else, instead of letting them answer the question that was meant for them.

I also don't believe that my answer to the original question reflected my "Simply looking for that seal/sig (or feeling for the raised seal... the 'braille' method)".

Thanks,

Uncle Bob

So if you're not qualified to review engineers plans, then you accept an architect's seal as well.

Since you are not qualified to practice architecture either.

 

[Uncle Bob]

Re: 16' Garage Door Headers

Brudgers,

"So if you're not qualified to review engineers plans, then you accept an architect's seal as well.

Since you are not qualified to practice architecture either."

You either didn't read my statement correctly; or your just being disputatious.

I stated that;

"I'm afraid that as an Inspector; I'm not qualified; nor should I be expected to be qualified to judge Engineered Designs (signed and sealed) that exceed the codes."

I used the codes to conduct plan review of plans that are submitted by an Architects; the same as I would any other person who isn't qualified to submit Engineered plans.

Where the plans are submitted within the limits of R301; whether they are designed by an Engineer, Architect or anyone else; I used the codes to conduct the plan review.

I have had many plans submitted by Architects; and where they were not qualified to specify structural components that were outside (exceeded) the codes; they deferred to qualified Engineers; instead of assuming that they could submit their own calculations and drawings. I suppose there are Architects who believe that their unqualified opinion should be accepted; but, like I stated; I haven't had to deal with those.

Uncle Bob