Hot take: Folks say slate is always flat, but my find says otherwise.
I found a chunk of slate that's all wavy and folded. Everyone acts like it's supposed to be even sheets, but nature isn't that tidy. It got me questioning how we label rocks too strictly.
Just like people when the in-laws visit... everything gets a little wavy under pressure. Sealing might help the slate but good luck finding a fix for mother-in-law stress.