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Didnt realize mortar color shifts that much until a school job
I was doing a repoint job at an old middle school in Tulsa last spring and matched the mortar to the original spec. The new mix looked perfect in the bucket, gray and gritty just like the old stuff. But after it dried for two days, I walked back and it was way lighter, almost chalky compared to the existing joints. Turns out the lime ratio in the old mortar was way different because they used a local sand that had more iron in it. I had to tint the whole batch with a little buff oxide and even then it took three tries to get close. The school maintenance guy kept saying, it looked fine from the road, but I knew it was off up close. Has anyone else had to chase mortar color on a historic building, and how do you test it before committing the whole wall?
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noahwood1d ago
The "looked fine from the road" part is exactly why the chalky look was fine, nobody staring at a school wall from 50 feet is gonna clock a slight shade off. Chasing a perfect match on old mortar is kinda a lost cause anyway, that local sand with the iron in it isn't something you can buy off a shelf, so you'll never truly nail it no matter how many oxide tries you burn through.
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