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How hardwood flooring is made

Hardwood floorboards air-dry for months, then go in a kiln until they reach 6 to 8 percent moisture.

stations
6
things upstream
15
raw sources
7
steps from the ground
5

The short version

Hardwood logs are sawn into rough boards, air-dried for months and finished in a kiln so they will not warp. Planers bring them to thickness, and moulders cut tongue-and-groove edges. The boards are graded and sanded, then ship either unfinished for coating on site or with a factory finish already on.

  1. Saw the logs into boards

    Logs are cut in one of three ways, plain-sawn, quarter-sawn or rift-sawn, which changes the grain pattern on the face of the floor.

    Goes in
    Timber

  2. Air-dry and kiln-dry

    Boards are stacked in moving air for several months, then finished in a heated kiln. Controlled moisture keeps them from warping or shrinking after installation.

    6 to 8% moisture

  3. Plane and grade

    Planers bring boards to an even thickness. Graders sort them by color, grain and defects like knots, and rustic grades keep more of those marks.

  4. Mill tongue and groove

    Cutters add a tongue on one side and a matching groove on the other, so neighbors lock together. Some makers also cut relief grooves in the back to reduce cupping.

    about 3/4 in solid boards

  5. Sand and finish

    Boards are sanded smooth. Prefinished floors get stain and a protective polyurethane coat at the factory. Unfinished boards are left bare so the installer can sand and coat them after nailing.

    Goes in
    Polyurethane

  6. Bundle for shipping

    Each board gets a final check, and boards are bundled in cartons.

End of the lineHardwood flooring

Worth repeating

  • Polyurethane floor finishes date to around 1942.
  • A floor refinish can take as little as 1/32 of an inch of wood.
  • Engineered wood flooring glues layers at right angles to one another, which makes it more stable than a solid plank.

Back to the ground

Follow every input upstream and hardwood flooring starts as these 7 raw sources.

TimberWaterCrude oilAirRock saltNatural gasSulfur

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Keep walking

Naphtha 5 stations · 3 raw sources Wheelbarrow 9 stations · 23 raw sources Solder 6 stations · 10 raw sources Match 5 stations · 9 raw sources Epoxy 6 stations · 7 raw sources Blender 7 stations · 30 raw sources

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Sources

Cite this page: "How hardwood flooring is made." Assembly Line, 2026-11-03. https://assemblyline.org/make/hardwood-floor

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