Can I lay new flooring straight over floorboards?
Floorboards move, cup and have gaps, so most new floors want a layer of board over them first. Whether you can skip that depends on the state of the boards and the floor going down.
- Difficulty
- intermediate
- Time
- 45 min
- Read
- 3 min
Short answer
Check the boards are sound, secure and reasonably flat, and that nothing underneath needs access. A floating floor can go over good boards with underlay, laid at right angles to them. Cupped, springy or gappy boards want overboarding with plywood or hardboard first, and glued-down floors nearly always do.
Suspended timber floors are the awkward case. They move with the seasons, individual boards cup and crown, there are gaps between them, and there are usually services underneath that somebody will want to reach one day. None of that rules out laying over them, but each one changes the answer.
Step by step
- Deal with what is under the floor first.Pipes, cables and stopcocks under floorboards become inaccessible once a new floor is over them. Anything that might need attention — an old valve, a suspect joint — is far cheaper to sort out now.
- Fix every loose or squeaking board.Screw the boards down properly where they move, having established there is nothing beneath the line you are screwing into. A squeak covered by a new floor is a squeak forever.
- Check for cupping and crowning across the boards.Lay a straightedge across the boards rather than along them. Cupped boards give a washboard surface that a floating floor will telegraph and that a glued floor cannot follow.
- Check for rot and damp before covering anything.Soft, dark or musty boards, particularly near external walls or under a bathroom, need investigating rather than covering. Also check the underfloor vents outside are clear.
- Lay a floating floor at right angles to the boards.Running the new boards across the old ones spreads each new board over several old ones, which reduces how much of the underlying unevenness comes through. Running them parallel does the opposite.
- Overboard where the surface is not good enough.Plywood or hardboard fixed down over the whole floor gives a continuous flat surface. It adds height, and it must be fixed at close centres or the sheets themselves move.
- Do not seal the floor up airtight.A suspended timber floor is ventilated from below for a reason. Blocking airbricks or sealing every gap can create the damp conditions that cause rot. Draught-proofing is fine; sealing the ventilation is not.
- Let everything acclimatise before laying.Timber-based flooring over a timber floor is two moving materials. GuideHQ has a guide on acclimatisation and what it actually achieves.
Tips
- Mark the line of any pipes and cables on the boards before covering them, and photograph the floor. Somebody will thank you.
- Hardboard should be laid rough side up for glued finishes and needs conditioning before fixing, or it buckles as it takes up moisture.
Common mistakes
- Laying new flooring parallel to the existing boards. — Each new board sits over one or two old ones and follows their movement and unevenness rather than spanning it.
- Covering a floor without fixing the squeaks. — The noise is coming from the boards, and burying them does nothing except make the fix expensive.
Questions people ask
Do I need to fill the gaps between boards?
For a floating floor, no — the underlay handles it. For a glued floor or where draughts matter, yes. GuideHQ has a guide on stopping draughts from floorboards.
Is hardboard or plywood better for overboarding?
Plywood is stiffer and better where the boards are uneven or the floor will be glued. Hardboard is thinner and cheaper and suits a reasonably good floor where height is tight.