Repairing wooden floorboards

Original wooden floorboards are a desirable feature in an old property but can deteriorate over time, so find out how to maintain, care for and repair them with this expert advice

TODO alt text

The rich patina of old wooden floorboards that are uneven with wear and have been scrubbed or polished for generations, contributes immensely to the special interest of many old homes. This is worth respecting and is often much more appealing than the appearance of floors that have been newly stripped or sanded to remove old finishes.

A good carpenter who understands the value of floorboards will generally be able to repair them and, wherever possible, should be employed to assist ahead of any work that necessitates boards being lifted. Non-powered hand tools should always be used when working with old floors and it is advisable to number any boards that are taken up with chalk so they can be correctly re-laid.

wooden floorboards in sitting room

Traditional wooden floorboards have a pleasing patina with signs of wear and tear adding to the charm

Wooden floorboards: warning signs

As well as general wear and tear, wooden floorboards are vulnerable to damp, rot, beetle infestation and damage caused when they are lifted by electricians and plumbers. Problems are often hidden under carpets or furniture.

What to look for:

  • Cracked, split or damaged boards
  • Beetle infestation revealed by small holes and fine powder
  • Damp and rot
  • Loose boards and creaking or ‘springy’ floors
  • Gaps between floorboards
  • Scratches, marks or surface damage

Upstairs, downstairs

At ground floor level, timber floors are generally suspended. The floorboards are nailed at right angles to joists, generally carried on ‘sleeper’ walls of brick with a damp-proof course, often of slate, included in the construction. The underside of a suspended floor must be ventilated to avoid the build up of moisture and the potential for rot, so grilles are incorporated at the base of external walls to ensure a good cross draught.

Upstairs, timber floors were constructed with floorboards nailed over wooden joists supported by the walls to the rooms below. Floor and ceiling joists also play an important structural role in helping to tie the main outer walls of the house together.

General care of wooden floorboards

Wooden floorboards are vulnerable to scratching and softwood boards can quickly become dented, so protecting and caring for the floor is essential. Sanding or rigorously scrubbing floorboards can destroy the surface character and, where woodworm is present, may reveal worm-ridden timber that is difficult to consolidate.


  • Sweep or vacuum regularly to remove grit.
  • Think before cleaning, sanding or polishing as this may destroy the floor’s character and always carry out tests on a small inconspicuous area first.
  • Use adequate mats at exterior doors and shake them out regularly.
  • Put felt pads on chair legs or furniture that is moved to avoid them scratching the floor.
  • Protect floors with hardboard or plywood sheets during building work.
  • Where necessary, apply a suitable finish. Beeswax is traditional for wooden floors but it can be high maintenance. Hard wax oils are an alternative and may be reapplied when required.

Localised old woodbeetle boreholes are very common and rarely an issue for concern

Damp and beetle infestation

Timber that becomes damp is likely to rot and suffer beetle attack eventually causing boards to become soft or riddled with boreholes which, in serious cases, can result in structural problems. In bathrooms or kitchens with suspended timber floors, leakage from pipes, showers or sinks, or condensation, can cause rot to develop unseen. Similarly a leaking water supply may go unnoticed for years, causing the earth below the house to become saturated.

In most old houses there will be a number of old boreholes from past wood beetle activity. Although very common, this is usually superficial with only the odd short length of board sufficiently weakened to need replacing. Where the originals cannot be reused, reclaimed boards are widely available, or you can have matching new ones made from seasoned timber.

Rather than using chemical treatments, always identify the cause of the problem and treat it at source.


  • Look for places where the wood comes into direct contact with sources of moisture and
    create some separation between them.
  • Where the pointing in walls is eroded, or hard modern cement mortar has trapped damp, repoint the walls with lime mortar, which allows moisture to escape.
  • Where joist ends resting in damp walls have been eaten away, steel joist extenders can reconnect them with the wall, or tie joists back in by inserting stainless-steel ‘helibars’ sleeved through the wall from outside and embedded in resin to form a tight new connection
  • With suspended floors, check air vents are not blocked or damaged and ensure there is adequate ventilation underneath.
  • Where the problem appears serious, lift boards to enable the joists below to be inspected.
  • Remove debris under suspended floors that is creating a bridge for moisture.
  • Repair or replace any floorboards and timber joists that are rotten.

wooden floorboards joists supporting upper floor

Wooden joists support the upper floors in many old homes

Damaged wooden floorboards

Wherever possible, repair rather than replace original floorboards. When refixing boards it is advisable to use brass screws rather than nails in order to protect old lath and plaster ceilings below from hammer vibration.


  • Glue and cramp split boards back together, where necessary using screws drilled into the edges of the boards.
  • Repair broken ends, corners or edges of boards by using the appropriate species of wood and matching the grain pattern.
  • Weakened floorboards can be strengthened by fixing a length of new board to the underside, or running new battens underneath for support, screwed to the boards on either side.
  • Allow new timber to acclimatise before use so that shrinkage is minimised after laying.


Victorian floors weren’t built with any form of insulation to reduce heat loss, so the rooms downstairs can be a bit draughty if there are gaps at skirtings and between boards. These can be sealed with a bitumen-based mastic, by cutting small timber wedges to fit the gaps, or using special foam rubber strips that are easy to wedge in place, and once inserted expand to fully seal gaps.

It is also possible to insulate ground floors from underneath by lifting a few boards to gain access to the subfloor void and then placing rigid polyurethane or quilt insulation between the joists, supported on battens.

Loose and squeaking wooden floorboards

Floorboards become loose for a variety of reasons. Often it is simply that the fixing is no longer holding the board tight, but movement in a board may point to more significant problems, so investigate the matter fully. Take great care where lifting boards is unavoidable.


  • Nail the board back into place using special ‘cut’ floorboard nails to minimise any squeaks, first ensuring that no cables or pipes are immediately underneath where you will nail.
  • Strengthen from below by screwing battens back on to the joists.
  • Where boards might have to be taken up in the future, or there are fragile ceilings beneath that may be damaged by hammering, brass screws are preferable to nails for fixing.
  • Squeaks are sometimes silenced by puffing powdered graphite or talc between boards that rub together.

wooden floorboards in a study

Early floorboards were quite wide but over time became progressively narrower

Bouncy floors

A small amount of ‘springiness’ is not normally a problem in timber floors. If furniture in the room vibrates when the floor is walked on, consider appointing a surveyor to judge whether this is acceptable. Although builders sometimes skimped with thinner joists spaced too far apart, weak floors are generally the result of notches subsequently cut in them to lay pipes and cables – notches should be cut no deeper than one eighth of the depth of the joist, and not less than 30cm from the end – with boards often left loose or broken.


  • Floor joists can be stiffened by wedging blocks of wood between them, or strengthened with fresh joists bolted alongside.
  • Where holes and notches have been cut, attaching metal plates alongside can stiffen joists.

Gaps and draughts

Added together, the gaps between floorboards in a typically sized room can be equivalent to leaving a small window open.


  • Fill gaps with thin slivers of matching timber, proprietary draught strip systems or lengths of string pushed and glued into place – these can be stained to match the colour of the timber.
  • Wipe off the glue immediately to prevent it marking.
  • Seal the gap between the skirting board and the floor in a similar way.

wooden floorboards in kitchen

Replacement old wooden floorboards can be sourced from salvage yards


It might be possible to retain and cover old boards beyond repair but where this is unrealistic, replacement will be required. New boards may be needed where earlier floorboards have been substituted with a less appropriate material.

Replacement boards should comprise seasoned timber of a suitable species, dimension and finish. Use cut floorboard nails to lay the boards. Butt them as closely as possible beforehand with temporary wedges to reduce gaps.


A short history of wooden floorboards

Used initially for upper floors, from the 18th century wooden floorboards became popular for ground floor construction as well. Generally speaking, the wider a floorboard, the older it is.

Early wooden floorboards were formed by splitting, axing or hand-sawing oak, elm and

Over time, floorboards became progressively narrower and more uniform in size, with cheaper softwoods used. In Georgian and Victorian times these ‘inferior’ boards were invariably hidden either by carpets or by being painted to resemble hardwoods.

The underside of boards on upper floors could be left exposed or painted, plastered between the joists or underdrawn entirely with plaster together with the joists. Where a void was created, this could be filled with “pugging” (such as chaff or nut shells) for sound insulation. Early ground floors had minimal (often insufficient) ventilation below.

Tongue-and-groove wooden floorboards: Boards with a slot (groove) on one edge and a ridge (tongue) on the other, enabling them to be slotted together. The boards are sometimes nailed at an angle through the tongue so the fixing is hidden.

Square edged boards: Floorboards that are not tongue-and-groove.

Parquet: Hardwood blocks, glued to a subfloor, which are laid to form geometric patterns.