A foundational coating applied to timber surfaces before painting or finishing, it enhances adhesion, seals porous areas, and blocks tannins, thus creating a more uniform and durable final result. For instance, applying a quality undercoat ensures even paint coverage on a knotty pine cabinet, preventing discoloration and peeling.
Effective surface preparation greatly extends the lifespan and enhances the appearance of finished wooden projects. By sealing the wood grain and preventing moisture absorption, it safeguards against warping, cracking, and fungal growth. Historically, linseed oil-based preparations were common, but modern formulations offer superior performance and specialized properties like stain blocking and rust inhibition.