Removing old finishes from wooden floors
It is often necessary to remove old finishes (varnish, wax, oil, polish etc) from timber floors; it is especially important to remove the old finish before timber floors are sanded (the old finish will probably clog up the abrasive and so require repeated replacement) or before applying a new type of finish.
The biggest problem in deciding how to remove the old finish, is to know exactly what the old finish was as this will affect how the job is tackled. The notes in this article are for general guidance only, and they should be tried out by stripping a small area of the timber floor to ensure that the technique chosen effectively works on the actual old floor finish.
Safety: Note that White Spirit, oil and resin based finishes are highly flammable. Always ensure that the room is well ventilated, ensure that there are no naked flames in the room (including the sometimes forgotten exposed pilot lights on gas fires/cookers etc and sparks from electric motors) and that all material (rags, newspapers etc) contaminated are disposed of, or cleaned, in a safe manner.
Always clear the floor area of all obstacles, don't try to clean a floor around the furniture in the room,
Paint and varnish
Old paint and varnish on a wooden floor can be stripped off by using a suitable chemical paint or varnish stripper. Using a chemical stripper can be expensive (a large floor will require a lot of chemical strippers), and will be time consuming and messy. Always be guided by manufacturer's instructions when using chemical strippers and adhere to any precautions and ventilation requirements specified in the manufacturer's health and safety guidelines.
Special care must be taken to make sure that all traces of the chemical are removed from the timber, or is effectively neutralised before any new finish is applied, failure to do this may result in a chemical reaction with the new finish.
After using a chemical stripper, any area previously painted or varnished will be a different colour to any area un-painted or varnished.
The timber floor will need to be sanded to prepare the surface for a new finish. One advantage of using a chemical stripper is that the abrasive material used when subsequently sanding the timber should last longer; if the finish had not been removed, the abrasive would quickly become clogged.
Oil, wax and polishes
An oil, wax or polished finish should be removed by initially rubbing with a cloth soaked in white spirit (to soften the finish) and then using steel wool with white spirit to scrub the floor timbers.
When working closely with White Spirit, always use an appropriate respiratory mask and gloves, and ensure that the area is well ventilated.
Working in small areas of the floor, use the cloth to work the white spirit into the finish. As the finish softens, lift it off the timber by using a scrapper (then drop the soft 'goo' into either an old paint tin or onto old newspapers).
After the surface finish has been removed, rub steel wool with white spirit along the grain of the timber to lift the old finish from the wood, soak this 'dirty' white spirit up using cloth or newspapers (dispose of safely).
Using White Spirit to remove the old finish is messy and time consuming, but Oils, Waxes and Polishes soak into the wood grain and must be either completely removed or sufficiently diluted so that they will not react with any new finish.
Just sanding floorboards without first removing as much of these finishes as possible will result in the abrasive becoming clogged and possibly soften the old finish so that it will soak further into the grain of the timber.
After as much of the original floor finish has been removed from the wood, the floor needs to be allowed to dry out and then the floor will need to be sanded - see our other article on sanding timber floors.