Scrub the board with a wire brush or a piece of sandpaper to remove any old paint or dirt.
Wipe the slate chalkboard down with a damp cloth to clean it. Dry it with a towel.
Apply a coat of chalkboard primer with a foam roller brush in thin even strokes. Allow at least two hours for the primer to dry.
Open the chalkboard paint and stir it well with a paint stick. In dryer hot climates, thin the paint with 2 ounces of water per quart of paint. Spread the paint onto the slate board with a foam roller. Apply in light and even strokes and avoid excessive rolling. If a second coat is needed, wait four hours before applying it. Wait approximately three to six days before using the chalkboard.
Condition the chalk board by rubbing the entire board down with a piece of chalk and then erase it with an eraser.