The Stain Library

Material

MDF

Compressed wood fibre and glue that swells permanently when wet, protected only where it has been sealed, and replaced rather than repaired.

  • SurfacePorous
  • WashingSpot only
  • Colour run riskLow
  • Reviewed7 September 2026

What mdf can and cannot take

  • Heat Avoid
  • Water and soaking Avoid
  • Acids, including vinegar Avoid
  • Strong alkalis Avoid
  • Solvents Avoid
  • Chlorine bleach Avoid
  • Abrasives Use with care

Always test on a hidden area first and let it dry before you treat the visible mark.

General rules for mdf

The surface is usually painted, foiled or veneered and the edges usually are not, and that distinction is the whole page.

Wipe the faces with a barely damp cloth and dry immediately. Keep liquid away from any cut edge, any screw hole and the bottom of a panel, because those are bare fibreboard.

Once MDF has swollen, it does not go back. That is the reason for being careful rather than thorough.

Check the label

MDF is wood fibre and glue compressed into a board, and it swells irreversibly when it gets wet. Its makers say to use minimal water and dry thoroughly, and a swollen edge cannot be sanded or dried back to shape: the panel is replaced.

Stains on mdf

MDF is wood fibre bonded with resin and pressed into a board.

It swells irreversibly

Water causes the compressed fibres to expand, and they do not compress again. A swollen edge stays swollen, and sanding it flat removes material rather than fixing it.

Only the sealed faces are protected

Factory faces are painted, foiled or veneered. Cut edges, drilled holes and the undersides of flat pack panels are bare, and they are where water gets in.

It is common in exactly the wrong places

Kitchen cabinet doors, bathroom units, skirting and flat pack furniture, all of which meet liquid regularly.

Replacement is the repair

Which sounds drastic and is often the cheapest honest answer for a single door or panel.

Sources

What we checked and when. Where a manufacturer instruction disagrees with anything here, follow the manufacturer.

  1. How to clean skirting boards, Skirting World manufacturer

    UK skirting manufacturer guidance that MDF swells if it gets too wet so minimal water is used and the board is dried thoroughly, that a cloth should be damp and not dripping, that warm water with a few drops of washing up liquid handles most cleaning with sugar soap for tougher marks, that harsh chemicals are avoided, and that boards are dried with a fresh cloth rather than left to air dry because that causes streaking and water damage.

    Checked 7 September 2026

  2. Care and maintenance guidance, Atkinson and Kirby manufacturer

    UK wood flooring maker's guidance to clean spills immediately and not leave wet items on a wood floor, to damp mop with a well wrung mop or a barely dampened microfibre cloth, that steam cleaners and steam mops are not recommended, that oil based, wax based and ammonia based cleaners can damage the floor, and that an oiled floor is maintained by reapplying maintenance oil and polishing it until the surface looks uniform.

    Checked 7 September 2026

  3. Restoring water damaged wood floors, Sanding Wood Floors specialist

    UK floor sanding specialist explaining that cupping is where the edges of the planks raise into a cup shape, that water often leaves a dark mark in the wood, that the floor must be allowed to dry out first and that this may take several days, that sanding then removes the warped and damaged layer, and that a buckled floor or one with extensive mould growth needs replacing rather than restoring.

    Checked 7 September 2026