There’s something about sandpaper. In the excitement of building the ideal chicken coop, DIY coop builders often either don’t realize or underestimate the role of sandpaper in building a coop that lasts. But if you’re planning to apply a preservative, stain, paint, or other sealer to your chicken coop lumber, sanding it first is a must. Especially if the wood you’re working with is new and smooth.
I should mention first that most plywood should be ready to go as is. What I’m talking about here is dimensional lumber (2x2s, 2x4s, etc., called “timber” outside of the U.S.). The reason that lumber needs to be sanded first has to do with how it is milled and something called “mill glaze.”