How to Fix a Damaged Hardwood Floor

Written by modigliani brooks
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How to Fix a Damaged Hardwood Floor
Woodworm damage needs to be treated or removed (old wood image by Karin Lau from

It may be as simple as a water stain or as calamitous as rampant rot, but whatever the damage to your hardwood floor there is usually a solution. Once you know the tricks of the trade, you can remove unsightly stains, fill gaps, hide cracks, remove paint and even replace whole floorboards. With a little know-how and a few ingredients, you can revive that beautiful hardwood floor and ensure it lasts a lifetime.

Skill level:

Things you need

  • Sandpaper (fine)
  • Bleach
  • Wood stain
  • Finish such as polyurethane, varnish or oil
  • Treatment for rot and woodworm
  • Wood filler
  • Wood glue or carpenter's glue (eg. PVA)
  • Hammer
  • Nails (annular/ring, lost-head/jolt-head)
  • Nail punch
  • Circular saw
  • Hand saw
  • Drum sander and edging sander (optional)

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  1. 1

    Assess the damage. Some types of damage may be fixable, including: rot, woodworm, cracks, gaps, stains, paint spots. If a hardwood floorboard is broken or very badly damaged by rot or woodworm it may need to be removed and replaced.

  2. 2

    Treat any rot (wet rot, dry rot) and woodworm (or borer) by applying a product that treats all three problems at the same time. Some chemicals in these treatments will darken the wood (sometimes almost black) so if colour is important, test the treatment on a discreet part of the floor first. Fill holes and cracks with wood filler.

  3. 3

    Fix small cracks by applying wood filler that is a matching colour. Sand lightly when dry.

  4. 4

    Fill gaps between boards by using fillets (narrow pieces of wood). Measure the gap to be filled and cut a narrow piece of wood to fit the gap snugly. Put a layer of wood glue or carpenter's glue such as PVA (polyvinyl acetate) on both sides of the fillet. Place in gap, tapping lightly with a hammer to ensure it is flush with the floor. Wipe off any excess glue on the surface of the boards.

  5. 5

    Apply bleach carefully to any dark stains until the required colour is achieved (same as surrounding wood). For stains that have made the hardwood lighter, not darker, try applying a new coat of finish. If this does not work, sand the wood back lightly with fine sandpaper.

  6. 6

    Remove paint spots with a paint scraper or paint stripper. Sand lightly with fine sandpaper.

  7. 7

    Sand whole floor if required using a drum sander for the main part of the floor and an edging sander for the edges. Start with a coarse sandpaper and sand diagonally across the boards. Use a medium sandpaper and sand with the grain and finally a fine sandpaper and sand with the grain.

  8. 8

    Make the colour of the repairs match or blend in with the rest of the wooden floor by applying a matching wood stain. You may need to stain the repairs again if they do not match the rest of the wood or you can try a different coloured stain. Apply a protective finish such as polyurethane, varnish or oil.

  1. 1

    Draw a line on the floorboard where it needs to be cut and removed. If your floor is secured directly onto joists, the ends of the replacement board must be nailed at the joist line. If the floor is secured to a solid subfloor then you need only replace the damaged part.

  2. 2

    Lever up the end of the damaged board using a wide chisel. Support the board by placing a piece of wood or a hammer underneath it so it is raised up. Note: If the boards are tongue-and-groove, you have to remove the tongue on one side of the board before trying to lever it out. Remove the tongue by sawing through it with a circular saw set to the depth of the floorboard (usually 3/4 inch but double check or you could saw through the subfloor and joists).

  3. 3

    Saw the floorboard at the marked line and remove old board.

  4. 4

    If the floorboard is tongue-and-groove, saw off the tongue along one side with a circular saw or hand saw. When sawing, secure the board (with clamps) to prevent it moving around. If using a hand saw, ensure the tongue is lying over a large gap to allow the saw to move. If using a circular saw, set to the depth of the floorboard (usually 3/4 inch but double check).

  5. 5

    Nail new piece of floorboard in place. The nails will have to be surface nailed (through the top of the board) rather than secret nailed (where the nail is inserted at an angle through the side of the board into the tongue). Use lost-head/jolt-head nails and punch the nails just below the surface of the wood with a nail punch. Fill holes with wood filler, and sand lightly when dry.

  6. 6

    Apply matching stain and a protective finish such as polyurethane, varnish or oil.

Tips and warnings

  • Many old hardwood floors look better if they are not fixed perfectly. The cracks, occasional woodworm holes and variations in colour add to the character of the floor.
  • Fill cracks and nail holes with wood filler before staining to ensure final colour is more uniform.
  • Test stains, finishes and treatments on an unseen piece of floor first. They often react differently to different woods and the final colour may not be what you expect. You may need to test a few colours or finishes before settling on the one to use.
  • Use eco-friendly stains, finishes and treatments where possible. Many have fewer toxins and are not only less harmful to your health but are also less harmful to the environment.
  • Wood glue is often white but will dry clear. Wipe off any excess with a damp cloth, otherwise it will leave noticeable blobs and marks.
  • Always wear suitable protective gear. When working with power tools wear safety glasses, sturdy gloves and footwear,ear protection. Chemicals such as stains, treatments, and finishes, contain toxic substances so always wear rubber gloves, safety glasses and a suitable respirator.

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