A wooden floor is one of the few parts of a home that can become more beautiful over the years, provided it is refreshed from time to time. Scratches, grey walkways, stains and a dull or flaking lacquer layer are no reason to rip the floor out: solid parquet, old pine or oak floorboards and most engineered wood floors (also known as two-layer or multi-layer parquet) can be sanded and refinished. This article explains when sanding is really necessary and when a new top coat is enough, how the sanding works, what the difference is between lacquer, oil and hardwax oil, and what to look out for regarding dust, solvents, drying times, underfloor heating, old adhesive and listed buildings. If you would rather go for a completely new floor, read Choosing a new floor: vinyl, laminate, parquet or poured floor.
Sanding or just a new top coat?
Not every tired floor has to be sanded back to bare wood. The main question is whether the existing finish is still intact.
- Just refreshing is enough if the lacquer is dull and has fine scratches, but has not worn through to the wood anywhere. The tradesperson then cleans and degreases the floor thoroughly, lightly abrades the lacquer with a fine grit or a sanding pad and applies one or two new coats of lacquer. For an oiled floor the equivalent is a thorough clean and a maintenance treatment with oil, without sanding.
- Full sanding is needed if the lacquer has worn through on walkways and the wood has turned grey or black, if the lacquer is flaking or coming loose, with deep scratches and dents, with stains that have soaked into the wood, and if you want a different colour or finish, for example from lacquer to oil or the other way round.
- Borderline cases are a floor with an unknown old finish, such as wax or an old synthetic resin lacquer, on which a new coat of lacquer may not adhere properly. A tradesperson often tests this first in an inconspicuous spot.
If you refresh in good time, you need to sand fully less often. That matters especially with an engineered floor, because every sanding removes wood that does not come back.
How often can your floor be sanded?
With solid parquet and solid boards, the whole board is made of wood, and it can be sanded down to just above the tongue and groove with which the boards interlock. Such a floor can therefore be refreshed many times over its lifetime. With old nailed boards, however, the tradesperson watches out for nail heads, which must first be punched in deeper to spare the sandpaper and the machine.
With an engineered wood floor, only the top has a layer of real wood, the top layer or wear layer, on a backing of plywood, softwood or HDF. How often you can sand depends directly on the thickness of that top layer. Common engineered floors have a top layer of a few millimetres, and each full sanding usually removes a few tenths of a millimetre to a millimetre or more, depending on how deep the damage goes and how level the floor is. A floor with a thick top layer can therefore go under the machine several times, a floor with a thin top layer perhaps once, and veneer parquet, with a very thin wooden top layer, as a rule not at all. Laminate and vinyl have no wooden top layer at all and cannot be sanded.
If you do not know what kind of floor you have, you can often find out yourself: remove a skirting board or a floor grille, look at a transition strip or at the end of a stair tread, or lift a board near a cupboard. From the cross-section you can see whether the board is made of one piece of wood or of layers, and how thick the top wood layer is. A floor layer can also measure this for you before making a quote; a thin top layer calls for a more careful sanding approach.
The sanding process: grits, edges and repairs
Professional sanding is done in stages, from coarse to fine. The tradesperson works with a large floor sanding machine (a belt or drum sander) for the open area, an edge sander along the walls and a scraper or small sander for corners and under radiators.
- First pass. With a coarse grit, the old lacquer or oil comes off and unevenness is removed. How coarse depends on the finish and the condition: a thick old lacquer layer needs a coarser start than a lightly worn oiled floor.
- Intermediate passes. These are followed by one or more passes with ever finer grit, sanding away the scratches from the previous pass. A rule of thumb in the trade is not to skip more than one grit step, because otherwise the finer grit can no longer remove the deep scratches from a much coarser pass.
- Final pass. The final pass with a fine grit determines how smooth the wood becomes and how it takes the finish. Many tradespeople then go over the whole floor with a flat sander or sanding pad to blend the transition between edge and open area.
For the first pass on an uneven floor, the tradesperson often chooses an angled or diagonal direction; the final passes run along the length of the boards, so that any sanding marks follow the wood grain. With herringbone and other patterns it is different, because the grain runs in two directions.
In between the sanding passes, repairs are carried out. Loose parquet strips or blocks are glued down again, a damaged board is replaced with a matching piece (patching in), creaking boards are secured and deep holes are filled. Dark stains in oak, for example from a leaking plant pot, sometimes go so deep into the wood that they cannot be sanded away; replacing the piece is then the only solution.
Finally, the gaps are filled. The usual method is a gap filler mixed with the fine sanding dust from the floor itself, so that the filling gets the same colour; this paste is spread over the whole floor into the gaps and, once dry, sanded off with the final pass. Wider gaps in old boards are sometimes closed with glued-in wooden slivers. Bear in mind that wood keeps moving with the seasons: during the heating season gaps can open up slightly again, even after filling.
Lacquer, oil or hardwax oil
The choice of finish determines the appearance, the maintenance and how you repair damage later.
- Lacquer forms a hard, closed film on the wood. A lacquered floor is resistant to stains and moisture and easy to keep clean. Lacquer is available from matt to high gloss. The drawback is that scratches in the lacquer layer remain visible and that local repair is difficult: damage cannot be touched up invisibly, so when it wears you re-lacquer a whole area or the whole floor.
- Oil soaks into the wood and shows off the grain and texture well. An oiled floor feels more natural and can be repaired locally: you can lightly sand a scratch or worn spot and oil it again, without leaving a visible edge. On the other hand, an oiled floor needs more frequent maintenance, with a special cleaning product and periodically a maintenance oil, and is more sensitive to stains from, for example, water, wine or grease if they are left for a long time.
- Hardwax oil combines oil with waxes. The product soaks into the wood and leaves a thin protective layer on the surface, making the floor somewhat more stain-resistant than with pure oil, while local repair remains possible. Many tradespeople see it as a middle way between lacquer and oil.
In addition, before the finish you can add a colour with a tinted oil or stain, or make the wood lighter with a white oil or a lacquer with white pigment. Ask the tradesperson for a test patch on your own floor, because the same colour turns out differently on oak than on pine. In a kitchen or hall with a lot of foot traffic many people choose lacquer; in a living room where the look of the wood matters, more often oil or hardwax oil. The most important criterion is what maintenance you want to do.
Water-based or solvent-based: the VOC rules
Lacquers and oils contain volatile organic compounds (VOCs, vluchtige organische stoffen or VOS in Dutch): solvents that evaporate during drying. Inhaling them can cause headaches, dizziness and, in the long run, damage to the nervous system, the well-known painters' disease OPS, nowadays called chronic toxic encephalopathy (CTE). That is why strict rules apply to professionals. Article 4.32a of the Arbeidsomstandighedenregeling (the Dutch Working Conditions Regulation) limits the VOC content of, among other things, lacquers, stains, varnishes, fillers, oil- and wax-like products and floor coatings applied indoors in buildings, to at most 100 grams per litre of ready-to-use product; for wall paint the limit is even lower. Adhesive for floor coverings has its own, even lower limit.
In practice this means that a floor layer or painter working indoors almost always uses water-based lacquer and oil, or products that contain so little solvent that they stay below the limit. Modern water-based parquet lacquers are hard-wearing and give off less odour and fumes during the work. One difference you can see: solvent-based lacquer and oil often colour oak warmer and more yellow, while water-based products leave the wood lighter and more natural. If you want that warm tone, ask for a water-based product with grain-enhancing properties or a tinted oil.
The VOC rules apply to employers and, via article 9.5 of the Arbobesluit (the Dutch Working Conditions Decree), also to self-employed tradespeople, but not to you as a private individual doing your own DIY. Even for DIY, Milieu Centraal (the Dutch independent information centre on energy and environment) recommends water-based oil, wax or lacquer, and an extra period of good ventilation if you do use a product with solvents.
Wood dust and your health
Sanding produces large quantities of fine wood dust, and that is more than a cleaning problem. Hardwood dust, from oak among others, is classified as carcinogenic in the Netherlands and Europe, and there is a statutory exposure limit for employees of 2 milligrams per cubic metre of air, averaged over an eight-hour working day. In addition, according to the Arboportaal (the Dutch government's working conditions portal), the employer must aim for a much lower value. Softwood dust, from pine for example, can also cause allergies and irritation of the airways and skin and is suspected of being carcinogenic. In 2026 the Gezondheidsraad (Health Council of the Netherlands) published new recommended limits for wood dust that apply to all wood dust, so to hardwood and softwood dust alike.
A professional floor layer therefore works with machines with good dust extraction, often connected to a separate extraction unit, and wears respiratory protection where necessary. For you as the occupant this means: keep doors to the rest of the house closed, tape up gaps, move textiles and uncovered food out of the way and have children and pets stay elsewhere during the sanding. Afterwards the room is vacuumed with a vacuum cleaner with a good filter before the finish goes on; otherwise dust left behind ends up in the lacquer.
Wood dust is also flammable. Used cloths and pads with oil or hardwax oil can catch fire through spontaneous combustion if left crumpled up, because drying oil generates heat. After use, lay them out flat outside to dry or keep them in a closed metal tin, and do not leave a full dust bag from the sanding machine indoors either.
Ventilation, drying time and curing time
A floor that feels dry has not yet cured. That difference matters for when you start using the room again.
- Between coats. Water-based lacquer can usually be recoated after a few hours, so the tradesperson can apply several coats in one day; there is often a light sanding between coats.
- Walking on it carefully. Walking on it in socks is usually possible after about a day, depending on the product, temperature and humidity.
- Putting furniture back. Light furniture can usually go back after a few days, with felt pads underneath; do not slide anything across the floor but lift it.
- Rugs and full load. Lacquer and hardwax oil continue to cure in the weeks after application. Only put rugs and mats back once the manufacturer indicates that the finish has fully cured, often after about a week and, depending on the product and conditions, sometimes later, and do not wet-mop the floor during that period.
Ventilate well during and after the work, but avoid draughts and bright sun on the wet coat, as these can cause uneven drying. Most products have a minimum application temperature; in an unheated house in winter a floor dries much more slowly. The manufacturer's technical data sheet is decisive; ask the tradesperson which periods apply to the product used and have them included in the quote or handover instructions.
Underfloor heating
A wooden floor over underfloor heating can be sanded and finished as normal, but it requires some extra care. Manufacturers of parquet lacquer and oil usually advise turning the underfloor heating down or off a few days before finishing, and gradually turning it back up after drying, so that the finish does not dry too quickly and the wood does not suddenly shrink or swell. A thin coat of lacquer or oil changes little in the thermal resistance of the floor, but with a floor that is already at the limit of what is suitable, a rug can.
Be extra careful when sanding an engineered floor over underfloor heating: such floors are often glued down and sometimes have a thinner top layer, and a sanding machine that stays in one spot too long goes through it more quickly. You can read more about combining floor and heating in Underfloor heating or radiators.
Old and historic floors: asbestos and permits
With old floors, it is important to know what lies underneath before any sanding, demolition or repair is done. In homes built or renovated before 1994, asbestos may be present in black bitumen adhesive under parquet blocks or mosaic parquet, in sheet vinyl with a felt-like backing and in old floor tiles. As long as the material sits undisturbed under the floor the risk is small; sanding, scraping or breaking it loose, however, can release fibres.
If you come across black adhesive or a suspect underlay during a repair, stop and have a sample tested first. Removing asbestos is in most cases work for a certified asbestos removal company, and there are rules on notifying the municipality. You can read how to recognise asbestos and which steps to take in Recognising asbestos when renovating. A good floor layer will ask about the year of construction and the floor build-up of old floors themselves.
If you live in a rijksmonument (national listed building), the protection generally applies to the whole building, including historic floors, and you need an omgevingsvergunning (environmental permit) for changes. Necessary regular maintenance aimed at preserving the monumental values does not require a permit as long as the detailing, profiling, design, type of material and colour do not change (article 13.11 of the Besluit activiteiten leefomgeving, the Dutch Environment Activities Decree). Sanding and finishing a historic floor in the existing way may fall under that, but a different colour, switching from a historic wax or oil finish to lacquer or replacing sections with different wood may not. Consult the municipality in advance; for municipal listed buildings the rules are in the omgevingsplan (zoning plan) or the heritage bylaw, and they differ per municipality.
Even apart from the permit, an old floor calls for restraint. Historic pine or oak boards have often been sanded before and are thinner than they look, and signs of use are part of their value. A tradesperson experienced in restoration sands as little as possible and chooses a finish that matches the original. The Working Conditions Regulation makes an exception to the VOC limits for restoring or maintaining historic finishes in national listed buildings using the original technique, so traditional products may be used there.
Sanding yourself or hiring a floor layer?
A floor sanding machine can be hired from many DIY stores and hire companies, and a handy DIYer can refresh a floor with one. The risks are real, though:
- Waves and sanding dips. A heavy machine that stands still for a moment while the belt or drum is turning sands a hollow into the floor in a few seconds. Such waves are clearly visible after lacquering and cannot be removed without losing a lot of wood.
- Through the top layer. With an engineered floor with a thin top layer, one clumsy sanding is enough to expose the backing. That cannot be repaired without replacing boards.
- Uneven edges. The edges and corners are sanded with other machines and easily end up a different colour or sheen from the open area.
A professional floor layer or parquet specialist has heavy, well-adjusted machines with extraction, assesses the top layer and the condition of the floor beforehand, carries out the repairs and knows which product suits your use and your wood. An average living room is generally sanded and finished within a few days, including drying time between coats. If you do choose to do it yourself, practise first in a small room, never let the machine stand still while it is running, start with a grit that is not too coarse and wear a dust mask with a good filter class. You can read more about what you can do yourself in What can you do yourself in a renovation and what is better left alone.
The quote and choosing a tradesperson
Ask for at least two quotes and make sure they contain the same items. A good quote for sanding and finishing states:
- The number of square metres and which rooms, stairs, thresholds and skirting boards are included.
- The type of floor and, for an engineered floor, the measured thickness of the top layer.
- The number of sanding passes and the grits, and how the edges and corners are treated.
- The repairs: regluing, patching in, securing, and how the gaps are filled.
- The product with brand and type (lacquer, oil or hardwax oil), the colour, the sheen level and the number of coats.
- How the dust is controlled and what you need to do beforehand yourself, such as clearing the room.
- The schedule, including drying and curing time and when you can use the room again.
- Maintenance advice after completion and the guarantee on the work.
What mainly determines the price is the surface area, the condition of the floor and the number of repairs, the type and thickness of the old finish, the chosen product and the number of edges, stairs and corners. You can read how to compare quotes in Comparing quotes.
When choosing a tradesperson, look for experience with your type of floor, ask for photos or references of comparable work and check the registration with the Kamer van Koophandel (KvK, Chamber of Commerce). If you buy the floor or the work through a home furnishing store, ask whether the store is CBW-erkend (CBW-recognised), a recognition for home furnishing stores affiliated with the trade association INretail; such stores work under a recognition scheme that includes a product guarantee, an arrangement for your deposit in case of bankruptcy and access to an independent disputes procedure. A recognition is not a guarantee, but it is a sign that the company is willing to be bound by agreements.
In short: if you refresh in good time, the floor needs to go under the machine fully less often. If it does have to be sanded, first have the top layer and the subfloor assessed, choose a finish that suits the maintenance you want to do, and give the floor time to cure. On VerbouwPro you post your job free of charge and floor layers from your area respond.