How much stone veneer overhang is too much?

[HouseBoy]

I have a stone veneer that will bear on the concrete ledge at the top of the foundation wall with 1" overhanging.
The stone is a "cut stone" so very uniform thickness of 3" and 4" to create some surface texture. All stone will bear 3" on the concrete (i.e. some will project 1" and some 0" beyond the face of the concrete ledge.
The way that I am looking at it is that bearing contact for the veneer will be within the middle 1/3 of the stone so..... there should be no net tension on the bearing.
Veneer anchors will be with Wire-Bond #1004 type III screw on veneer anchor with #1100 triangular ties.

Any technical issues with the amount of overhang?

Yes I would prefer to have less overhang but adding a plate or angle at the bearing ledge will be problematic and half of the stones will be the 3" thickness so, seems like the CG will be sufficiently behind the edge of the bearing.

 

[jayrod12]

1" is fairly typical around here. We usually shoot for 3/4" and take anything between 0 and 1". We don't generally allow more than 1" as at 3 5/8" thick you're starting to go past that whole 1/3 2/3 deal.

 

[Ron247]

Same as jayrod, 1" max for 3.625" brick.

 

[JAE]

We aim for a minimum of 2/3 of the veneer width.

Check out Eng-Tips Forum's Policies here:
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[HouseBoy]

Thanks to all. Just just wanted a "sanity" check.
It seems sensible to me but the masonry sub is being real squirrely about it for some reason.
(Usually, it's the other way around!!)

 

[HouseBoy]

NEW PROBLEM......

Now we have a 4" ledge (at the top of the concrete wall) and the stone veneer is 4", 5" and 6" thick (NOT the 3,4,5" we were told initially).
They will place the stone with 1" air space so the overhang will be 1", 2" or 3". I'm not comfortable with that.

I want to fasten a SS plate or angle to the face of the concrete.
If we use an angle, I'd want the outstanding leg to be trimmed to 1 1/2" or 2" max and would make the bottom layer stick out 2".
Vertical leg would be 6" min (maybe 7 or 8").

My questions are having to do with the attachment to the vertical face of the wall - How much edge distance would you want and what type of anchor would you prefer to use?
The dilemma with increasing the edge distance is that it decreases the "force couple".

Anybody ever use a flat plate anchored to the top of the concrete? Still, only will get about 3" edge distance but seems like the weight of the stone will contribute some to the stability and the plate is much less visible.

Any thoughts or other ideas?

Thanks,
Steve

 

[spieng89]

You could anchor to the top of wall, but it may get tricky bearing the veneer on top of the anchors, unless the wall has not been poured then you could use an embed plate. For anchoring into concrete, I've used expansion and epoxy anchors depending on the capacity I need. I base anchor spacing on manufacturer table requirements with a minimum 3" spacing I try to maintain regardless

 

[HouseBoy]

Thanks spieng89. Was hoping they could "hide" it in the 3/8" setting bed. Guess I'd need to specify short nuts. (I think there is a name for those.)

The loading requirement is kind of funky to me.
How much load will really be on the angle/plate?
Seems like it will be related to the relative stiffness's (in some respects anyway). I mean, most of the weight will be on the wall and we are only using the angle/plate to provide resistance for that portion which is outside of the kern and really how is that load going to get to the plate? Trying to strike the right balance between being correct and being "overdone". First priority is to be correct though.