Question about installing a stone facade

[Harpist]

Hi folks,

The snow is pretty much gone from around my pizza oven project. Last year I got the oven done and this spring and summer I am working on the facade (and thus my question).

The base of my oven is concrete block and I have been gathering ledgestone from the nearby mountains. My question is what is the best way to prepare the concrete blocks. I have always used corrugated brick/wall ties for this type of work with no other surface preparation for the concrete blocks. However, I have a friend (who has a lot of experience with rock where they have prepped the back of the stone by shaving it to a flat surface) that uses a wire mesh that is then covered with a bonding material.

Can someone let me know the best way of prepping the concrete block for laying a ledgestone facade?

Thanks

Harpist

[Tscarborough]

Re: Question about installing a stone facade

It is two different methods entirely. If you have a ledge to stack the stone and tie it to the CMU, then that is the fastest, cheapest way.

If no ledge, then you can cut the stone thin enough to adhere it to the CMU. Stone can be up to around 2" thick done with this method, but most are cut to 1" to 1-3/4" thick. The adhered veneer standard is <14# per Sqft. You can use Type S mortar to adhere the stone directly to the CMU. No ties are used.

[Harpist]

Re: Question about installing a stone facade

It is two different methods entirely. If you have a ledge to stack the stone and tie it to the CMU, then that is the fastest, cheapest way.

If no ledge, then you can cut the stone thin enough to adhere it to the CMU. Stone can be up to around 2" thick done with this method, but most are cut to 1" to 1-3/4" thick. The adhered veneer standard is <14# per Sqft. You can use Type S mortar to adhere the stone directly to the CMU. No ties are used.

Tscarborough,

Thanks for your response. I haven't done stonework like this since before Nixon resigned so I look for expert advice whenever possible. Glad to hear that techniques have not changed too much since the days of the oil embargo.

What is the best way to attach the ties to the CMU? If I had thought ahead, I would have embedded the ties in the CMU joints. Masonry nails would split the CMU (even if it is reinforced with concrete).

Thanks again

Harpist

[Tscarborough]

Re: Question about installing a stone facade

Tapcons, ties at 16" vertical, 24" horizontal.

[Harpist]

Re: Question about installing a stone facade

Tapcons, ties at 16" vertical, 24" horizontal.

Perfect. That is exactly what I had purchased for the ties (even a blind hog finds a few acorns).

I was planning on installing 1 1/2 angle iron for the ledge. Any recommendations on the best way of anchoring that? My plan was to use expansion bolts (although they are a bit of a pain to drill).

Thanks for your responses. These details are difficult to track down for a DIY weekend mason like myself.

Harpist

[Paul in Rockwall TX]

Re: Question about installing a stone facade

Hello Harpist,

I experimented with attaching mesh (for stucco) to CMU with deck screws I had hanging around. I dry set the blocks, so I just screwed the coated deck screw into the joints (with small washer on the screw).

the coated screw went right in with no cracking of the block.

turned out alot easier than drilling every hole for a tapcon, even though that's pretty fast when going into soft blocks like that.

[Faith In Virginia]

Re: Question about installing a stone facade

I hate Tapcons...but that's just my personal experience. I always have a problem with them making a strong connection. But that's just me.