Stone veneer bearing on CMU, where below grade

[McSEpllc]

Hi All,

A project I am working on has concrete basement wall, with the top 3-ft or so that are exposed to be faced with 6” stone. When supporting the stone veneer on 6” CMU on the below grade part, does this 6” CMU have to be fastened to the concrete?

Instead of vertical dovetail slots and ties, I am thinking to use HDG corrugated ties fastened with powder actuated fasteners for the stone veneer (and CMU if needed). Do you see a potential concern on this?

Thanks!

 

[phamENG]

Sounds to me like the CMU is just a continuation of the veneer, albeit below grade. Standard veneer anchorage should suffice, though below grade I'd be sure to grout the joint between the CMU and the concrete so make sure the tie selection won't interfere with that. Is there an economical way to step the concrete wall so you don't have to have CMU at all?

 

[masonrygeek]

I agree with PhamENG about filling the space between the CMU and concrete. My personal opinion is that corrugated wall ties are a piece of crap, unless they are 14 gauge or something like that. There are better (stiffer, more corrosion resistant) wire and plate ties such as H&B's 345-BT Flexible tie that would be better than corrugated wall tie.

 

[msquared48]

Fully grout the CMU too as it is below grade.

Mike McCann, PE, SE (WA, HI)

 

[dhengr]

McSEpllc:
Why not just cast the shelf into the outside face of the conc. wall like a corbel. Provide a 5” wide shelf which can step periodically to follow the grade. The bottom of this thickened wall section should be about 12” or 18” below the shelf elev., and there should be some longi. horiz. rebar at the outer face, along with some enclosed #4 rectangular cage/shear type reinf. tied around the inner face horiz. wall reinf’g. The found. guy will bitch about all the wall forming work, but that can’t be any worse than messing around with the whole conc. blk. wall detail, whatever that looks like. You do still have to tie the stone veneer to the conc. wall per code. You should show us what you think the above detail will look like, and what the top of conc. wall/wood framing/top of stone detail will look like. I assume that the loading on this shelf is primarily the weight of the stone veneer.

 

[r13]

What climate is this project subjected to?

 

[McSEpllc]

Thanks All for your thoughts!

Yes, Pham, the CMU is essentially the continuation of the stone veneer below grade. Quite a bit cheaper and faster to construct.

Makes sense to grout the voice between CMU and concrete foundation wall.
Also, I will call out the '345-BT' for ties - thanks Masonrygeek fore that insight.

Msquared48, I usually call out for CMU foundation walls to be grouted solid. It reduces water infiltration, no standing water inside the cells, gives mold less to work with, and I believe reduces the chance of spalling under freeze/thaw. For an this I am not sure grouting it solid is worth it. I usually call out for the top 8" to be a solid block.

Dhengr, this project is in the mountain of NC. It is harsh for wood construction, but not too bad for masonry. Frostline is 18" below grade.

 

[structSU10]

I agree with Dhengr with widening the frost wall for a shelf - is your footing that shallow or is there a basement? I generally use a brick/stone shelf in the concrete wall in my area and our frost depth is 4-5'.