Grout Mortar Color - exterior stone veneer

Old 09-17-21, 06:42 PM
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Grout Mortar Color - exterior stone veneer

I don't have any photos that illustrate what I'm about to write, but I'll try to describe what I'm running into.

I used a Quikrete product CSC-4, a modified mortar for natural and manufactured stone. I did the scratch coat and the back-buttering of the (natural) stones, and all of them are installed. As I looked at the scratch coat, it seemed too light and contrasty - so I bought a bag of mortar pigment.

My idea was to mix the colorant at a lesser ratio - so I made up a batch and upon mixing it, it was quite dark. I adhered a small stone to the wall with this mix, and made a test piece with the remainder to see what color it cured to. About a week later, and I'm a bit, well, confused.

The mortar that's holding the stone to the wall is, well, very dark.

The test piece of mortar I made (a 1/2" thick 5" circle) is much lighter.

So I'm just not sure what to expect. I want a darker mortar than how plain CSC-4 turns out, but I'm concerned there will be some interaction with the stones that causes the mortar to be darker when installed as grout.

Thoughts? The place I bought the mortar/colorant from was, well, less than helpful. It may sound like I'm putting way more effort into this, but would like to do the grouting once and be happy with what I do
Old 09-17-21, 10:20 PM
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I'm concerned there will be some interaction
Cement based products are pretty inert so I doubt anything is going to effect the color but as you noted the color can easily change based on mix ratios not to mention that it's going to fade with time and sun exposure.

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