How to Varnish a Wooden Floor?

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 opions available, with wood cut from guaranteed sustainable forests and certified by the Forest Stewardship Council.

Worn and damaged varnished wooden floor

Worn and damaged varnished wooden floor

So how to you keep your stunning, warm, welcoming wood flooring in perfect nick? 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 soft woods. 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 VOC (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 stain is difficult with solvent pu floor finishers 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

  1. 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
  2. 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.
  3. 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.
  4. 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.
  5. 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.

Varnished wooden floor needs refinishing

Varnished wooden floor in need of repair

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 maybe necessary to offer the optimum protection.

How to apply solvent-based polyurethane varnishes?

Apply a thin coat with a fine brush or micro fibre 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 maybe necessary to offer the optimum protection.

Wooden floor preparation in 8 steps

  1. The better you clean the room before starting, the better the eventual finish. 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.
  2. 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.
  3. Fill in any gaps in the floorboards if you need to or want to.
  4. 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.
  5. Safety first… always unplug the sander when you need to change the paper.
  6. 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.
  7. 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.
  8. 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 9 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.

Tags: , , , , , , ,

18 Responses to “How to Varnish a Wooden Floor?”

  1. David Ryan Says:

    Wonderful post. Thanks for share it.

  2. Chris Says:

    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.

    Chris

  3. Sam Taylor-Casey Says:

    Hi Chris,

    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 Solvent Stains for use under Manns Extra Tough Floor Varnish.

    For more advice please do not hesitate to call us on 0800 7818 123 or 01303 487978

  4. Andy Says:

    Hi, we’ve just converted our loft , the floor boards
    Are brand new what would be the best finish to go for!
    Thanks Andy

  5. Sam Taylor-Casey Says:

    Hello Andy,

    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.

  6. Steve Gasper Says:

    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

  7. Sam Taylor-Casey Says:

    Hello Steve,

    Its well worth you having a chat with our floor finishing expert, he will be able to advice 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. You can call us on 0800 7818 123 and ask for Merv or email and let us know how best to contact you. And we will be able to help with your project.

    All the Best Sam.

  8. Steve Gasper Says:

    Of course the one answer I get is trying to sell me something.

  9. margaret Says:

    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?

  10. Sam Taylor-Casey Says:

    Hello Margaret,

    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.

  11. Januce Says:

    Is it hard to varnish your own floor? Or should I get it done my someone.

  12. Sam Taylor-Casey Says:

    Hello Januce,

    Have a watch of some of the videos on our You Tube 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. https://www.youtube.com/watch?v=Umn0CgJpdSg

    Kind regards Sam.

  13. Renee Says:

    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.

  14. Taylor Says:

    Hello Renee,

    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 wood@finishes.direct 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

  15. Lily Says:

    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.

  16. Samantha Taylor Says:

    Hello Lily,

    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 wood@finishes.direct.

    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.

  17. Jill Says:

    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?
    Many thanks
    Jill

  18. Samantha Taylor Says:

    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 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.

Leave a Reply