Brick Shelf Angle supported on wood

[bvbuf]

ACI 530-13 Sect 12.2.2.3.1.2 says brick height with a backing of wood framing shall not exceed 30' above support.
ACI 530-13 Sect 12.2.2.3.1.3 says brick height with a backing of metal studs shall not exceed 30' above support. Above 30' support with non combustible construction at each level.
ACI 530-13 Sect 12.2.2.3.1.5 says brick height up to 12' can be supported on wood construction.

How would you interpret this? I have brick veneer going up 33' backed by wood.
A. I can only build the brick up 30' above the brick ledge in the foundation.
B. I can build the veneer up to 33' as long as I attach a shelf angle to the wood framing and it supports no more than 12' of brick.
C. I can build the veneer up to 33' as long as I attach a shelf angle supported by non combustible construction at 30' or below.

Please Advise

 

[jayrod12]

I would vote for b. but I'm not directly familiar with the ACI codes.

 

[JAE]

Per 12.2.2.3.1.2 - you cannot go over 30 ft. with a wood framed system.

The sections that says you can support veneer on wood doesn't mean, in my view, that you can then go over 30 ft.
It only suggests that you can support that veneer under the 30 ft. limit with angles at 12 ft. centers.

So A. is what I would see as correct.




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[jayrod12]

that's 30 feet vertically supported laterally by wood only at least the way I read it, however if you were to break it up into 12 foot vertical lifts, then it should be acceptable in my eyes, The trick will be accounting for shrinkage of the wood.

 

[JAE]

Well they have the section for light gage studs where they specifically allow you to support higher than the 30 ft. table limit on shelf angles at 12 ft. but there isn't a similar section on wood.





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[mike20793]

I agree that it should be A. There are other reasons why you would want to support the brick at each individual level, especially in wood design.

 

[structSU10]

This has always been a gray area. This part of the code is considered the prescriptive limitations - if the system is 'engineered' you can go past that limit, but there is no 'engineered' method outlined, and the code stated you must have your method approved by the building code official. From this, you can go above 30' as long as you pay attention to thermal expansion, freezing expansion, moisture expansion and the like for the brick veneer, and then detail all attachments to the backup to accommodate differential movement. This gets trickier at window and door openings and such.

 

[bvbuf]

You guys are great! I appreciate the input. I originally thought option A was correct for the same reasons JAE proposed. (Higher veneer is specifically stated for metal studs but not for wood). As I was typing this post, the building code official called for another reason and I asked him the question. He is going to allow me to use option B.

 

[XR250]

The detailing and construction is so tricky, IMHO, that I won't even touch one of those jobs.
Try adhered, thin brick

 

[mike20793]

I second the thin brick. We have had good luck convincing architects to use it rather than conventional brick as of late. Once we mention lipped brick at shelf angles and the range of expected shrinkage, architects tend to shy away from the brick.

 

[Ron]

Agree with thin brick; however, you need to make sure the thin brick is designed properly for waterproofing. It is essentially a stucco system with thin brick as the finish. Make sure the substrate is well protected from moisture.

 

[XR250]

I imagine even with thin brick, careful detailing is required to address wood shrinkage

 

[structSU10]

on a somewhat recent job with brick with wood backup we had the architect change the façade in certain areas so we could just stack from the foundation. Even when stacked from the foundation, differential movement around windows is a pain. they agreed to use a different material under the windows so the brick was straight fields with no opening in it. Worked very well - obviously not many archt's will agree to such a thing, but they were bit by a lawsuit where when the brick moved up and wood down, the window sills went from a positive slope away from the building, to a slope towards the building, and rain water was getting in.

 

[KootK]

I typically include it for new stuff. In an unshored application where all of the supported block would go up in one shot, however, I think that you could make an argument to not.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.