Foundation for Brick Veneer - vertical extension ok?
Foundation for Brick Veneer - vertical extension ok?
(OP)
I'm working on a 4 story bldg with exterior gage steel studs. Brick veneer runs from the foundation all the way up. Per ACI 530-02, 6.2.2.3.1.3, the height limitation for the veneer above the foundation is 30 feet, with veneer supported by relief angles at each floor above 30 feet.
Here's the rub. The veneer is double thickness for the first two stories. The inner wythe at the lower stories is 4" CMU. The concrete foundation extends up to the top of the first story (steel studs above that point).
The contractor argues that the CMU can be considered the foundation, so that the full height, single thickness veneer is less than 30 feet above the 'foundation' and no relief angles are required.
Can the 4 inch CMU be considered an vertical extension of the foundation this way? It makes some sense to me, but I'd like to get some feedback.
Thanks
Here's the rub. The veneer is double thickness for the first two stories. The inner wythe at the lower stories is 4" CMU. The concrete foundation extends up to the top of the first story (steel studs above that point).
The contractor argues that the CMU can be considered the foundation, so that the full height, single thickness veneer is less than 30 feet above the 'foundation' and no relief angles are required.
Can the 4 inch CMU be considered an vertical extension of the foundation this way? It makes some sense to me, but I'd like to get some feedback.
Thanks






RE: Foundation for Brick Veneer - vertical extension ok?
RE: Foundation for Brick Veneer - vertical extension ok?
RE: Foundation for Brick Veneer - vertical extension ok?
RE: Foundation for Brick Veneer - vertical extension ok?
Thanks for looking at this. I'm in agreement with haynewp and jae. If the 4" cmu was to be a couple of feet high, I could justify reinforing it and calling it foundation. Of if I had solid masonry walls behind, I'd grout the collar joint and call it good. But in this case, I think I'm going to call for the relief/shelf angles.
Do any of you know the rationale behind the height limitation? Is it differential movement? Any links to industry/code docs that discuss the rationale?
Thanks again.
RE: Foundation for Brick Veneer - vertical extension ok?
The reason that the relief angles are installed is to allow for the expansion of the bricks as they absorb moisture. The higher the wall is without the relief angles the higher the differential between this expansion and the shrinkage of the concrete/timber backing.
This would mean that your veneer ties would not be horizontal and would not act as they are designed. Also in extreme cases it would cause cracking in windows e.t.c.
Get the builder to put these in or you could be blamed for any serviceability issues in this wall.
RE: Foundation for Brick Veneer - vertical extension ok?
RE: Foundation for Brick Veneer - vertical extension ok?
Clay brick has an irreversible long term expansion. This is opposite to other materials that have srinkage or creep, especially under loads. Iy you were dealing with concrete brick, the situation does not exist.
The reason for the angles is to keep the exterior veneer in approximate vertical alignment with the structure. The typical problem down the road is usually evidenced at the upper part of the building where difference in height is the greatest. Wall ties have been known to break and leaks at windows are common.
To me, calling the 4" CMU backup a foundation is a stretch, unless there is something I do not see.
Proper use of the angles is prudent.
Dick
RE: Foundation for Brick Veneer - vertical extension ok?
The Shelf angles are in.
RE: Foundation for Brick Veneer - vertical extension ok?
Dik
RE: Foundation for Brick Veneer - vertical extension ok?
RE: Foundation for Brick Veneer - vertical extension ok?
RE: Foundation for Brick Veneer - vertical extension ok?