Wood is beautiful, natural and non-toxic. No wonder people love wooden floors so much, whether it’s top quality modern solid wood products or beautiful old hardwood floorboards.
Wood is easier to keep clean than carpeting, is much less welcoming to house mites and dust – great if you suffer allergies – and these days there are plenty of sustainable, environmentally friendly options available, with wood cut from guaranteed sustainable forests and certified by the Forest Stewardship Council.
So how to you keep your stunning, warm, welcoming wood flooring in perfect condition? We get a lot of enquiries about how to varnish a wooden floor, so here’s some sensible guidance for our customers. As usual, if you have any questions feel free to call us, or have a look on our interior floor varnish page for more information. We have a team of wood-obsessed experts on hand to help!
Varnishing a wooden floor – About polyurethane varnish
First, you need to decide on your varnish. Do you need an oil-based, solvent-based or water-based varnish?
- Oil-based polyurethanes, although easier to apply, are now rarely used as they tend to add a lot of colour to the wood, can take an age to fully cure, potentially weeks, and have a short shelf life. Two or three coats usually does the trick. But bear in mind it’s smellier than water-based products, prone to brush marks and takes a lot longer to dry than the alternative solvent or water-based varnishes.
- Water-based polyurethanes dry faster and smell less, but they can raise the wood’s grain slightly on some softwoods. This isn’t a problem as the process of denibbing between coats will help to keep the final finish smooth. Water-based polyurethanes don’t go well over oil-based wood stains but work well over solvent-based wood stains and white-spirit based stains. Most pros use water-based varnishes because they have virtually no smell.
- Solvent-based polyurethanes are very quick to dry but are also the most smelly due to their high V.O.C (Volatile Organic Compound) content. Solvent-based varnishes are normally only used where very tough, fast curing is called for such as bar tops, sports halls and night clubs. Using solvent-based stains is difficult with solvent pu floor finishes because of the speed they dry. Solvent-based varnishes can be troublesome for novices who have no experience. They are probably better off sticking with water-based varnishes which are easier to use and give comparable results.
5 top tips for using polyurethanes
- You should always apply varnish to bare wood. In theory, you should be able to varnish over an existing varnish but there is always a possibility that the 2 types of varnish may react with each other. If this is to be attempted, always do a test area, wait for 24 hours, then do a thumb nail scratch test to ensure that the new varnish has adhered or bonded to the old coat.
- Never, ever shake a container of polyurethane varnish, whether it’s oil, solvent or water-based. Shaking it will fill it with air bubbles, which will stick around when you use the product. Stir it gently between each coat instead.
- Always work in a clean, dust-free, well ventilated area. If you’re varnishing a floor, open the windows and doors but try to keep draughts to a minimum in case they blow dust on your finish.
- You can thin oil-based polyurethanes with mineral spirits, but it isn’t usually necessary. It’s almost always fine used straight from the tin.
- When applying the varnish, whether oil, solvent or water-based, it helps to study the finish from different angles. Different amounts of light and the direction of the light itself make it easier to spot places where you’ve over-brushed, left brush marks, or missed bits altogether.
How to apply oil-Based polyurethane varnishes?
Use a fine bristled brush, clean cloth or foam brush – beware of cheap brushes, which often leave unsightly hairs behind as well as making obvious brush strokes.
Brush the varnish in the same direction as the grain and don’t put it on too thickly. Don’t brush the same area again and again. And use long brush strokes, which help get rid of any bubbles in the product. Any tiny bubbles left at the end of the process should disappear quickly. Sand lightly (denib) in between coats.
How to apply water-based polyurethane varnishes?
Apply a very thin coat with a fine brush or foam pad. Work in the same direction as the wood grain. To avoid raising the grain don’t apply too much at once – it’s much better to be safe than sorry, so take it easy. The first coat ought to dry in a couple of hours and while you don’t have to lightly sand (denib) between coats, professionals usually do, as it can help to achieve a smoother finish. If using a primer, 2 coats of water-based lacquer are usually enough; if not using a primer, then 3 coats may be necessary to offer optimum protection.
How to apply solvent-based polyurethane varnishes?
Apply a thin coat with a fine brush or microfibre roller. Work in the same direction as the wood grain. Keep the room well ventilated at all times by opening doors and windows and be aware of the quick drying times. As with water-based varnishes, if using a primer, 2 coats of solvent based lacquer are usually enough; if not using a primer, then 3 coats may be necessary to offer optimum protection.
Wooden floor preparation in 8 steps
- The better you clean the room before starting, the better the eventual finish will be. Dust and dirt can stop sandpaper being as effective as it should be and also makes an awful mess of your varnish if you don’t do everything you can to keep things spotless. Some people even hoover the walls and ceiling to make 100% sure there’s minimal dust.
- Hire a special floor edging sander and you’ll easily be able to sand right up to the edges of the floor without having to get down on your hands and knees and DIY the fiddly bits.
- Fill in any gaps in the floorboards if you need to or want to.
- Depending on the condition of the floor, you may need to start sanding with a coarser sandpaper. Start at one end of the room and sand with the grain. Use less coarse sandpaper, usually around a 120 to 150 grit abrasive to get a lovely, smooth finish.
- Safety first… always unplug the sander when you need to change the paper.
- Let the dust settle then vacuum thoroughly to get rid of every last speck. Then wipe the surface clean with a cloth and white spirit or a damp (NOT wet!) mop and let it dry thoroughly.
- Whether you’re using a brush, cloth or pad, apply two to three coats of varnish with adequate drying time in between – check the tin for the manufacturer’s recommendations. If it’s not fully dry, it will feel sticky. Make sure you apply the product in small areas of 4-5 square feet at a time.
- Don’t walk on the floor for at least a day after you’ve finished the job.
Useful videos about varnishing wooden floors
Sometimes a video is the best way to get to grips with exactly what to do. Here are several excellent videos about varnishing wood floors:
Plus here’s a great Podcast from Sadolin: A step by step guide to great looking wooden floors.
Recommended polyurethane varnishes for wooden floor maintenance
We stock a range of top quality polyurethane interior varnish products, all perfect for floors and each with its own special features. Feel free to browse them and don’t hesitate to contact us if you’d like help making exactly the right choice for your project.
Need help varnishing your wooden floor?
For more information about wooden floor varnish and its uses, contact our team of resident experts who are always on hand to help with project advice and product recommendations. Alternatively, see our floor finishes FAQ page which covers many of the most commonly asked questions about floor finishes.
We love to see before, during and after photos of any wood finishing project. If you would like to share your project pictures with us and our followers, you can either send us some photos or share on our Facebook, Twitter, Pinterest or Instagram pages.
Thanks for this useful article. I’d like to sand, stain and varnish the floors in my first floor flat. But I’m worried about the stain and the varnish dripping through to the floor below and spoiling their ceiling. How do I avoid that?
Good Afternoon Gisella,
Thank you for getting in touch with your enquiry. Worry not, I do not think this is going to be an issue for you. There is likely to be a series of materials between you and your neighbours ceiling, including insulation. And whilst application does not need to be particularly thin, you are not going to be pouring the product directly on to the floor.
Using a tray and application pad system will give you good control over the product and spreading it across you floor evenly and with out drips.
We do have some great videos on our You Tube Channel >>> https://www.youtube.com/user/WoodFinishesDirect with hints and tips for preparation and applications. Or you can get in touch via our contact us page.
Kind regards Samantha.
Hi – I’ve applied osmo raw on my oak parquet floor and am happy with the colour it’s produced. I’m not sure whether the second coat should be another coat of raw or the normal osmo Matt clear? I’ve got both and have read advice saying both can be used but not sure if the raw will lighten it further or risk some white residue remaining. Thanks for any help.
Good Afternoon James,
The best and only way to tell for sure is with test areas. I would always recommend full test areas before application. This should include the preparation and all coats of products to be used. This is because the wood type age and condition will all have an impact on the result.
Especially on parquet which can be a difficult floor type to prepare well. I would recommend two coats of the Osmo Polyx Oil Raw over one coat of the Raw and one coat of the Clear Osmo Polyx Oil as the clear is likely to either darken the result or yellow and possibly high light the white in the first coat.
It is possible that you will get a slight white appearance, the best thing to do is try a test area of both option and see which result you prefer.
If you need any further advice please do not hesitate to get in touch via our contact us page.
Kind regards Samantha.
I have dark parquet flooring and it has several scruff marks all over (there is no other damage to the floor – just very small dents which are barely noticeable). I have tried everything to remove the marks (vinegar, wall eraser, olive oil mixed with vinegar, toothpaste) – literally everything and the marks are still there.
I have tested sanding the marks and they have come off but also has the varnish and the finishing.
Do you think it’s a good idea to keep the sanding and varnish the floor? If so, what products do you recommend?
I have spent a lot of time researching and I cannot decide if it’s best to use an oil or water based varnish. Any advice you can provide will be more than welcome!
Thank you for getting in touch with your question. How frustrating, it sounds like you have tried a few things to improve the overall look. Another thing you can do for small dents is to iron the area. This will only work with dents and not gauges and on bare wood. Put a couple of drop of water on the area affected and then place a cloth over the wood, hold the iron on the area, the steam will expand the wood and reduce the dent.
For the areas that you have sanded and removed the varnish, you can patch repair, however you are likely to see join marks and our best advice for an even all over result will be to sand back the whole floor and start again. If you need some advice on this please feel free to get in touch via our contact us page or give us a call and one of our advisers will be happy to help.
Kind regards Samantha.
Hi. I had my kitchen floorboards done with a water based polyurethane. After 24 hrs I put mats down, and beneath the rubber backed ones the finish has turned milky. How can I fix this please?
Good Morning Kathy,
Although the finish was probably dry and ready to put into light use, the varnish will continue to cure over a period of days and weeks. Covering the finish will prevent this curing from taking place and it is not advisable to place rugs or covering on the surface for at least 7 days.
If you lift all covering this may allow the product to then go back to curing, if it does not match the rest of the finish after a period of time you may have to consider sanding back and re applying.
If you have any questions please feel free to get in touch via our contact us
Kind regards Samantha.
My varnish is peeling in spots. What is the best way to repair and what should I use?
Thank you for getting in touch with your enquiry. It very much depends on what we are talking about, floor, furniture or something else? And how extensive the damage is? If you are able to email me with some further details and photos of the effected areas I would be happy to advice further. You can email FAO Sam to email@example.com.
All the Best Samantha.
We have wooden floors and in some spots we have water damage and the wood needs to be sanded, stained and varnished. What method is best for partially repairing the floor
Good Morning Bev,
Apologies for the delay in getting back to you, we do actually have a blog about patch repairing Varnished finishes. Wood Flooring Varnish Repair this will help with your enquiry hopefully.
Repairing varnish is not easy I won’t lie but with a care and preparation you can get a reasonable finish. Feel free to get back to me if you have any questions.
Kind regards Samantha.
I’ve just sanded and revarnished my wooden floor, 2 coats of varnish and then a clear top coat. The floor now looks very dull and you can every fleck of footprints etc, is there anything I can do. It’s not the finish I was hoping for
I am sorry to hear that you have had a disappointing experience with your finish. Are you able to email me some details of the products that you have used, your method of application, and the type of wood you are applying to. Also you can send some photos I will be happy to take a look.
Kind Regards Samantha.
Hi is it possible to have a varnish with a grey greyish colour to it please?
Our lounge floor was sanded, grey wash applied and then varnished, but it does not have enough colour . Stains also are coming. Please can you advise?
Good Morning Jill,
Thank you for your enquiry. As the floor is varnished you will only be able to have varnish applied over the top and you will need to ensure the old and new treatment are compatible with a test area first.
Alternatively you can sand back to bare wood and look at an alternative product. The Blanchon Oceanic Coloured Floor Varnish. This one gives an opaque finish and has a grey in its colour range.
I hope that helps and if you have any further questions please do not hesitate to let let me know.
Kind Regards Samantha.
We have a floor company came and did sanding and vanish for our shop. However we discovered that it is not possible to clean the floor after the work is done. Foot prints on the floor can not be wiped out with damp cloth even I added wood cleaning product to the cloth. What are the possible reasons for it? I suspect there was not even coating applied.
I am sorry to hear of your disappointing experience with the floor finishing company. I would be happy to take a look at some photos if you would like to send some in to firstname.lastname@example.org.
My advice would be to get back in touch with the company that you used however and speak to them about what the current finish is and explain the difficulties that you are having with marks and cleaning.
Kind Regards Samantha.
We had our floors done by someone recommended to us. Mostly, existing hardwood was sanded, stained and then varnished with semi-gloss. On the second floor hallway, we had them put in new hardwood because of the extent of the damage on the existing hardwood. We liked the job but there were a few raised bumps in some areas on the second floor. The guys came and buffed the 2nd floor and some other areas and reapplied the same varnish (what was leftover in the bucket). Unfortunately, the buffed areas with a 4th coat of varnish now have a matt finished. How is this possible. The explanation by the floor guys doesn’t make sense to me. Thanks.
Are you able to send me some photos of the effected areas, some close shots and some of the whole floor and include a description of the product used and the number of coats and application method. You can email this to email@example.com and I will happily take a look. I can’t guarantee an answer but we have a number of experts with in the company and we will be happy to see what we can do.
All the Best Samantha
Is it hard to varnish your own floor? Or should I get it done my someone.
Have a watch of some of the videos on our YouTube Channel, they will give you an idea of how to apply varnish and if you have any questions then feel free to let me know.
Kind regards Sam.
We have just stained our wooden floor and put three coats of varnish on it.
it looks lovely but in parts it is still sticky. It has been a week now is this normal?
This would not be expected, are you able to send me any photos of the effected area and the whole floor area and I would be happy to take a look for you. Please include a description of the type of wood, preparation process, and how you applied the product. And any other information that you think is relevant and I will see if there is anything I can advice to help.
Kind Regards Sam.
Of course the one answer I get is trying to sell me something.
I have been asked to varnish the floor in a museum. I have 1200 square ft of 100 year old oak floor with plenty of other finish on it. My problem is they don’t want to lose any of its color so it cant be sanded to bare wood. they just want a coating over it to protect it as is. Can I do this? any tips would be great. Thanks Steve Gasper
It’s well worth you having a chat with one of our floor finishing experts, who will be able to advise you on the best way to achieve the finish you want on that kind of area. Also we need to know what is currently on the floor. Use the contact us form to provide further details and one of our experts will be in touch to offer advice.
All the Best Sam.
Hi, we’ve just converted our loft , the floor boards
Are brand new what would be the best finish to go for!
This would depend on the type of finish you are looking to achieve but as a starting point, Hard Wax Oils are very popular, because of their natural finish. They are easy to apply, maintain and patch repair if needed. There is also a tint range that will colour and protect in one treatment Fiddes Tints. Application of these oils needs to be very thin. Please feel free to ask if you have any further questions.
Kind regards Sam.
We have recently taken up the carpets in the living room of our Victorian terrace. We have replaced damaged boards with some from upstairs and shuffled them all up to elimiate big gaps. We now plan to sand the boards and then finish the floor, but I’m not clear on what the normal/”best” finish is… hoping you can give me some recommendations!
Would you generally recommend varnish as a finish rather than oil? I have read some articles that say varnishes that contain polyurethanes tend to give the wood an orange, ‘plasticky’ appearance, but I’m not sure that can always be the case! What about wax – is that harder work to apply?
Really grateful for any tips you can give.
Some finishes do give wood that orange kind of appearance but that is generally down to them bringing out the natural colours in the wood.
There are pros and cons when choosing between using a varnish and an oil! Although a varnish would be harder wearing, you will likely find that an oil or to be more specific, a ‘hard wax’ oil will be easier to maintain in the long run.
When it comes to avoiding that orange colour a great test to do is what we call the ‘wet test’ whereby you wipe a damp cloth along the surface of the wood, indicating what colour the wood will go once finished. If the colour is not to your taste you could then try test areas of tinted hard wax oils.
If you do chose to use a varnish, take a look at our Light Fast Wood Stains for use under Manns Extra Tough Floor Varnish.
For more advice please do not hesitate to contact us.
Wonderful post. Thanks for share it.