Priming is not required for most surfaces. Priming will always help for adhesion and covering surface defects. We recommend priming for woods high in tannins(cedar, redwood, mahogany and fir) and knotty woods. Priming these surfaces will prevent tannin bleed and cover rough surface defects. Simply prime the entire surface with a shellac base primer such as Zinsser® Cover-Stain®, Zinsser® B-I-N® Primer or Clear B-I-N® sealer according to the directions, and proceed with your project.