A. Tony Jucewicz responds: When matching existing mortar, I first try to decide whether a match can be achieved using "standard" mixing ingredients. The pointing mix I use consists of one part Portland cement and three parts sand. Portland cement is available in gray or white, and sand in my area is available in white, yellow, or brown. When gray cement is used in the pointing mix, the color of the sand has little effect on the final color of the mortar. When using white cement, you can control the color with the sand used in the mix. White sand will produce a white mortar, yellow sand a beige mortar, and brown sand a light brown mortar with a reddish tint.
In my area of Pennsylvania, I’ve had the best success matching the mortar found in older stonework by using white Portland cement and a mixture of brown and yellow sand. Before I begin pointing, I premix all the sand needed for the job. The premixed sand can then be mixed 3 to 1 with the cement.
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