Proper Procedures

Q:  We’re bidding a paving project and the specification calls for testing of the bond between the setting bed and the stone to verify 50 psi minimum bond strength. We were planning on using a conventional mortar bed with no additives. Will this meet 50 psi or should we plan on purchasing something of higher performance?

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Testing Split-Tail Anchors

Q: We are installing a small exterior façade using stainless steel strap anchors. The specs require us to test the anchors in the stone. We argued against that requirement, since strap anchors have been used in stone for generations and surely they’ve been tested before, but we were unsuccessful in that argument. We’re now getting

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Slab Waste and Hairpin Anchors

Q: Is there an industry standard for waste of slabs in layout? A: There is no published industry standard, although perhaps the most common figure that I have heard from those with accurate production materials tracking is in the neighborhood of 60% yield (40% waste). Obviously, this is HIGHLY variable. When cutting small pieces from

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Understanding Quartzite

Q:  We have been selling a quartzite for several months now, but we are getting complaints from customers that the material is etching. I thought quartzite was supposed to be acid resistant. Am I mistaken? A:  You are not mistaken. There seems to be a recent attraction to quartzite products, and it appears that from a marketing

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Silicone Caulking and Resin

Q: How long does it take silicone caulking to dry? A: Silicone caulking does not “dry.” Instead, it “cures,” and the cure time will vary from product to product, so you will need to check the manufacturer’s literature for specific times. Generally, most silicone products will be mostly tack-free in about an hour. Substantial cure

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Testing Aluminum Anchors

Q: I’m reviewing some anchor tests submitted on a project of ours. There are aluminum anchors that carry both dead load and wind load, but I only see testing performed in one direction. Why would they not be tested in both directions of load? A: Many of the anchors that we use for stone cladding

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Hairpin Anchors and Island Installation

Q: We need to test some hairpin anchors for a granite-clad precast project. Can we just test the anchors in the stone, or do we need the concrete on the backs? A: Normally, we test anchors engaged in the stone, without simulating any of the other backup structure. The precast hairpin is different, in that

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False Joints and Travertine

Q: Is there a rule of thumb for how deep a false joint can be cut into a 3 cm travertine stone? A: There is no “rule of thumb,” although shallower is better. Any time we make an abrupt profile change in a quasi-brittle material such as stone, we will create a stress concentration, often

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Measuring the Voids

Q: We recently had a stone consultant, retained by the owner, review our installation of a stone flooring. He removed several pieces, and then measured the voids in the bedding with a tape measure and determined that we were just under the required 80% coverage. Is this an accurate way to measure the voids? These

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Insulation Installation

Q: It seems that more and more frequently on exterior cladding jobs, stone installers are having to install the insulation. We’re not insulators – why does this get dumped on our trade? A: What you are seeing is a trickledown effect of the energy standard. This standard is authored by ASHRAE (American Society of Heating,

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