Polyurethane

Polyurethane is the go-to durable topcoat for floors, tables, and trim. This section explains poly types, how to apply and thin it, layering over stain or paint, and safety.

Basics & types: polyurethane vs urethane, best poly for floors, satin vs semi-gloss, and acrylic urethane vs poly.

Application: thinning poly, finishing a tabletop, and repairing a finish.

Over stain & paint: poly over stain, stain over poly, and paint over poly.

Safety: food safety and toxicity.

For the full finishing picture, see our wood finishing guide.

Is polyurethane food safe? Fully cured polyurethane is generally considered food-safe, but for cutting boards many prefer a dedicated food-safe oil or finish.

Can you apply polyurethane over stain? Yes — let oil-based stain cure fully (24+ hours), then apply poly; match oil poly to oil stain where possible.