How to Seal a Butcher Block Countertop

Butcher block countertop

John Keeble / Getty Images

Project Overview
  • Working Time: 1 - 2 hrs
  • Total Time: 1 - 3 days
  • Yield: Seal 8 linear feet of butcher block countertop
  • Skill Level: Beginner
  • Estimated Cost: $25 to $50

Butcher block countertops are beautiful, durable, and natural. One positive of butcher block counters is that they are easy to refinish. Sealing the butcher block protects the porous wood surface from water and food. Learn how to seal a butcher block countertop with polyurethane or with oil.

  • Hard finish

  • Infrequent reapplication

  • Avoid cutting on surface

  • Plastic shell-like look

  • Gloss or semi-gloss finish

  • Soft finish

  • Frequent reapplication

  • Can be used for cutting

  • Natural wood look

  • Matte finish

What You'll Need

Equipment / Tools

Both Methods

  • Electric oscillating sander
  • Sander discs: 120-, 220- , 300-, and 400-grit
  • Sandpaper sheets, assorted grits pack
  • Foam sanding block
  • Synthetic bristle paintbrush (for polyurethane only)
  • Clean microfiber cloths
  • Tack cloth
  • Breathing protection
  • Eye protection


Sealing With Polyurethane

  • Oil-based polyurethane coating
  • Paint thinner or mineral spirits

Sealing With Oil

  • 1 quart food-safe mineral oil or tung oil
  • Mineral spirits


How to Sand and Clean Butcher Block for Sealing

  1. Scrape the Butcher Block

    Scrape large food deposits with a plastic or metal scraper to avoid clogging the sanding disc. When using a metal scraper, avoid gouging the surface.

  2. Sand the Surface

    Sand the butcher block countertop in the direction of the grain with an electric oscillating sander. Begin with the coarse 120-grit sanding disc, then progress to 220-grit and 300-grit papers for a smooth finish.

  3. Sand the Edges

    Sand the edges of the butcher block countertop by hand, using a foam sanding block and loose sanding papers.

  4. Clean With the Tack Cloth

    Clean the butcher block top surface and edges with the tack cloth.

  5. Clean the Surface

    Clean the butcher block with denatured alcohol or paint thinner and a microfiber towel. Wear breathing protection and waterproof gloves.

How to Seal a Butcher Block Countertop With Polyurethane

Liquid oil-based polyurethane dries to a hard, shell-like finish. Polyurethane is water-resistant and long-lasting with careful use. Use cutting boards and avoid cutting directly on a polyurethane finish.

  1. Apply the First Coat

    Brush polyurethane coating on the butcher block. Do not over-apply. Work rapidly to blend edges with each other. Wear a hair covering. Hairs are difficult to remove from oil-based polyurethane, especially after the coating has hardened.


    Work only in a well-ventilated area.

  2. Coat the Edges

    While working on the first coat, brush the polyurethane over the edges of the countertop. Be careful of drips.

  3. Allow the Coating to Dry

    Wait four to six hours for the sealer to completely dry.

  4. Apply the Second Coat

    Apply the second coat of polyurethane to the butcher block. This coat will soak in less than the first coat.

  5. Clean the Tools

    Clean the tools with mineral spirits. Wait at least six hours before using the countertop.

How to Seal a Butcher Block Countertop With Oil

Mineral oil or tung oil create a soft, velvety, matte-like finish on butcher block countertops. Oil is water-resistant. Frequent reapplications are needed to maintain the water resistance.

  1. Apply the First Coat

    Add the oil to a microfiber cloth, then rub across the butcher block surface and edges.

  2. Wipe the Excess

    Wipe off any excess oil pooled on the surface with another clean towel.

  3. Let the Coat Dry

    Let the oil dry for about six hours.

  4. Scuff the Surface

    Lightly scuff the surface with 400-grit sandpaper. Clean the surface with a clean microfiber towel.

  5. Apply a Second Coat

    Apply a second coat of oil to the butcher block with a clean towel.

  6. Assess for More Coats

    Two coats of oil may be enough, but up to four more coats may be needed. Too much oil will cake up on the surface.

  7. Clean Up

    Clean up with mineral spirits.

  • What is the best sealer for butcher block countertops?

    The best sealer for butcher block countertops is either polyurethane or oil. Polyurethane's hard shell repels water, and it is as close as you can get to duplicating the surface of solid surface or quartz countertop materials. Mineral or tung oil soak into the wood, rather than sitting on top. Oil gives the wood a natural look.

  • Can you permanently seal butcher block countertops?

    Butcher block countertops cannot be permanently sealed. Whether the sealant is polyurethane or oil, refinishing will later be required. But polyurethane is permanent in the sense that reapplication is only required when the surface is damaged. Mineral oil must be reapplied every month or two, even if the surface is not damaged.

  • How many coats of sealer on butcher block countertops?

    Two coats of oil-based polyurethane sealer are required on butcher block countertops. Two to six coats of mineral or tung oil sealer are required on butcher block counters.