Location of control joints in brick veneer 4

[ali07]

We provide shelf angle to support brick veneer and also there is a limitation to the height of the veneer. Just need to know that control joint in veneer is dictated by architect or structures. Also is there any limitation regarding the depth available due the structural deflection reflecting in control joint. Can we make it 1" deflection in control joint. I am talking here for a 2 stories shopping mall facade.

 

[hokie66]

Ali,

The location and design of control joints in brick veneer, both horizontal and vertical, must be the subject of coordination/negotiation between the architect and structural engineer. I doubt that many architects would agree to a control joint allowing 1" deflection. Assuming 50% deformation of the sealant (which may not be achievable), the joint would have to start at 2" thick. Also, deflection of this magnitude would probably result in cracking of the brickwork above the joint. I think you need to make the supporting structure stiffer.

 

[ali07]

Thanks Hookie,

Is there any practical limitation to provide control joint horizontally. What is the maximum practical depth veneer can go vertically if supported on foundation and if supported on shelf angle with no control joint.

 

[Ron]

A continuous shelf angle is a control joint. Horizontal control joints are less of an issue from a building movement standpoint than vertical joints (they are essentially always in compression, but subject to shear in conjunction with the vertical joints).

 

[lkjh345]

Keep in mind that horizontal brick joints must not only accomadate the deflection of the structure supporting the brick above the joint, but also the swelling and thermal expansion of the brick below the joint. Swelling and thermal expansion can be a significant percentage of the total movement needed to be accomadated.

 

[rcd445]

The International Building Code limits deflection of horizontal members supporting masonry veneer to span (inches)/600. See chapters 14 and 24.
ACI 530.1 allows between 30' and 38' veneers supported on building foundations. Read the section on veneers for particulars.
If your building is less than thirty feet tall, you would be better off supporting the veneer on the foundation. If you must use shelf angles, they should be at each floor level.
As a practical matter, unless you have unusually sophisticated details for weatherproofing the control joint, 1/8" is about as much deflection that should be allowed.
I don't think 1" deflection should ever be permitted with masonry. Most of the reccomendations I have seen are for span/600 with a maximum of 3/8" and reccomendations of span/1200 are becomeing more common.

I wasn't sure if you were interested in the spacing of vertical joints but I attached a pdf with some information from a few different sources.

 

[msquared48]

The spacing depends on how much of a control freek you are...

Mike McCann
MMC Engineering

 

[ali07]

Appreciate guys for useful information provided.

 

[jike]

There are three different ways to do the brick at shelf angles.

1) Typical brick above and below shelf angle. This unfortunately will give the thickest joint = shelf angle thickness + 1/2 x compressible filler.

2) Notched brick above (to accomodate shelf angle thickness)
with typical brick below. Compressible filler thickness = mortar joint.

3) Typical brick above and notched brick below. Can accomodate thicker compressible filler in notched brick.

Method 3 is typically preferred over Method 2, although Method 1 can be used if shadow line can be created by offsetting brick or some other architectural feature to hide "thickness" of joint.

These considerations and directions that the architect should give you so that shelf angles can be set at the proper elevation. Shelf angle thickness usually does not exceed 5/16". Mortar joint thickness typically being 3/8". Max. movement = 1/2 x comp. filler.


I hope this helps!

 

[jike]

Oops! I made a mistake on the thickness of the joint for Method 1. It should be flashing + shelf angle thickness + compressible filler.

 

[AUCE98]

A good reference would also be the Brick Industry Association

http://www.gobrick.com,

they have some good technical notes.

AUCE98