What is floor sanding?

What is floor sanding? | Professional Floor Lacquers & Sealers

What is floor sanding? 

Any type of wooden floor sold by a flooring shop has some type of sealer on it. It is of course possible to buy unsealed wood floors but these floors will be sealed at a later stage. Some people buy wooden floors without a sealer so they can seal it later with a particular type of sealer or colour to match walls, furniture or a particular style. But at some point, all wooden floors will require sealing. Why? Because unsealed wood floors will stain very easily, are nearly impossible to clean, absorbs humidity from air and traffic and because unsealed wooden floors don’t really have a practical point. Even wooden floors that look “natural”, are 100% sealed but with a natural or invisible sealer. 

Floor sanding is the process of sanding the floor with a special heavy duty sanding maching so that the top coat of a wooden floor is fully removed and a new topcoat is applied. All hardwood floors (solid) and engineered wooden floors (semi solid) can be sanded once or a number of times.

Hardwood Floors – if the floor sanding is done right by a fully qualified floor sanding contractor using proper floor sanding technology, then a solid wood floor can be sanded at least 10 times over its lifetime. A professional floor sanding contractor should not remove more than 1-2 mm of wood from the floor during the sanding process. In most cases, the wood is hardly touched and instead only the old sealer is being removed. 

Engineered Wood – in the case of engineered wood, there is a limited amount of times the wood can be refinished. It all depends on the type of the wood and the thickness of its top layer. Some engineered wooden floors are very cheaply made and not really designed for refinishing or sanding. While most good quality engineered wood floors would have a good 10 mm of top layer, the cheaper ones can be as thin as 2-3 mm so it cannot take the weight of a heavy duty sanding machine. In the case of non sandable engineered wood floors there are polishing and recoating options without sanding being required. 

So before sanding a wooden floor you will need to assess it to make sure that the floor is actually wood and can be sanded. Many people have mistaken good quality laminate floors or amtico floors with real wood. Another essential piece of information that you should learn from this article is the fact that wood floors can only be sanded a limited amount of times so it is highly recommended to do it right from the start and use the best and most durable sealers to avoid having to do it again within 6 months. Premium quality sealers applied by professionals will provide long lasting protection for your floors and extend the periods between refinishing. 

What is floor sanding? What type of sealer can be on my floor?

All wooden floors are sealed. An exception may be if you are lifting up carpets and have just exposed the original floorboards, these floorboards are unlikely to be sealed. 

Assuming that your property is 5-50 years old, we can list a potential number of sealers that were used over the past 50 years up to now. Since the 1970s up to now the main sealers for all types of hardwood floors were oil based floor varnishes and hardwax oil. All older wooden floors that were sealed with those two products are very likely to have a dark yellow finish. The solvent that these products contain reacts with UV light and chemicals and changes colour over time. Initially the floor was nice and natural looking but over time has become darker. 90% of the older wooden floors were sealed with either an oil or a wax. Other sealers used were shellac, polyurethane & natural floor oils. With the advances in technology water based floor varnishes have become more popular. The water based lacquers/varnishes look much more natural, do not yellow and are unaffected by UV light. But they require a more specific maintenance than the old oil based finishes. Also, there are a number of organic floor oils that keep the natural appearance of the wood without glazing it. Some people also use water based polishes and sealers but these products do not provide a lot of protection. Usually they waterproof the wood. Of course, some people just paint their floors with a water based, acrylic or solvent based floor paint. 

What is floor sanding? Why is it important to know what finish is on the floor?

Knowing what type of sealer was used on your floor means that you can use the best and the most suitable products for that particular type of sealer. But if you are planning to sand that floor, knowing what type of sealer is on it can help you work faster & with alot less hassle. Why? Well, a polyurethane high traffic floor lacquer will require a lot of heavy duty sanding before you expose the wood, while a floor oil or a hardwax oil will be much easier to remove. Knowing what type of sealer is on your floor will enable you to prepare the proper sanding paper and the proper grit for sanding it. 

What is floor sanding? How do you tell what type of sealer is on the floor?

99% of people will have no idea and not a hope of ever finding out on their own. Wooden floors sealed with water based or solvent based floor lacquers should be much smoother and much more perfect than the oiled ones. Because varnished floors are getting a number of sandings between coats, the finish should feel like glass, with no imperfection when you touch it. Oiled floors on the other hand should feel a bit rougher to the touch and the grain of the wood should be a bit dirtier (oils penetrate fully and the fibre of the wood is usually left slightly less unsealed than the rest of the floor and in most cases it absorbs a bit of dirt). So wood floors with black dirt stuck in the grain are usually oiled. Varnished floors might have patches of black dots but not the whole floor.

To be 100% sure you should ask a floor refinishing company to help you out.

What is floor sanding? Should you do it on your own?

If you are not that bothered about the final results and if you are doing it in your own home, it is possible. But if you have fancy floors that can only take a limited amount of sandings, you should hire a professional floor sanding contractor. Floor sanding is not an easy job and you need to be physically fit and have some DIY skills to do it properly. The first step is to do the maths and see if it is worth it to do it on your own. We assume that you plan to sand a 40 sq meter floor (standard living room & dining room in Ireland).

  1. You will need to hire a sander for a week 
  2. You will need 10 sheets of sanding paper for each grit from 40 to 100
  3. You will need to hire an edger as well 
  4. You will need to get 10-20 sanding discs from each grit starting from 40 grit
  5. You will need brushes, rollers, a roller frame, a large bucket & a handle
  6. You will need 3 x 5L bottles of floor lacquer

Now also ask a floor sanding contractor for a free no obligation estimate and see if you can actually save money. While a floor sanding company should have your job fully completed in about 10 hours, it will take you about 1 week of hard work to complete it. Why? 

Because the hire centres are not usually hiring the latest technology within the floor sanding industry. Because the sandpaper you are likely to receive with the sanders is not the best. Because the lacquers you are likely to buy are not professional quality. Because you do not have the experience and the skills that a professional has. Saying that, we are not saying that DIY floor sanding is impossible. But it is not easy and most DIY floor sanding jobs usually end up looking unfinished or not professionally done. In most cases paying a bit extra to use the services of a professional contractor makes more sense.

What is floor sanding? How do you do floor sanding on your own?

You will have to source a quality drum or belt floor sanding machine. A drum floor sander usually works with sheets of sanding paper while a belt sander usually works with a belt. Most hire centres hire drum sanders because the belt sanders are very expensive and more suitable for the professional floor sanding industry. Both types of floor sanding machines work pretty much the same way. 

Install the most appropriate sanding paper – usually start with 40 grit for heavy duty sanding and then finish with 80 or 100 grit. You need to go through the grit to prevent deep scratches that can be very visible after you seal the floor. 

The sanding machine you have just hired has an on/off button and a dropoff & lift up handle. Basically you will need to hold the drop off handle slowly until you can feel abrasion on the floor and then move backwards slowly. Make sure to slowly move backwards even when you first drop the sanding paper on the floor. Move up and down the floor going along the fibre of the wood. Make sure to also hire an edger to sand up all the areas around the skirting boards or all narrow areas where the sander cannot fit. Also use a small hand sander to sand corners and sand areas that look scratched. Now that you are pretty much done with the sanding, you should plan the next step, the sealing. 

What is floor sanding? What is the best sealer?

Even if you have sanded your own floor with DIY floor sanders, it does not mean that you need to buy cheap lacquers or hardwax oils. The difference in prices between high traffic floor finishes and low cost low traffic floor finishes can be huge. But the difference in protection is also huge. After all that work and all the effort, the last thing you need is to seal your wooden floor with a sealer that wears off in 6-12 months. 

Low cost floor lacquers : 20 to 70 euros per 5L

Durability : 6 month to 36 months

Premium quality floor lacquers : 90 to 200 euros

Durability : 24 months to 120 months

There is a fine process to follow while sealing wood floors. You want to respect the drying periods and you want to apply at least 3 coats of lacquer or 2 coats of floor oil. If you like the way oil feels, you can use a hardwax oil like Carver Greenoil HD, one of the best high traffic hardwax oils available on the market. If you are looking for a floor lacquer, you need to decide if you are likely to stain the floor before varnishing. If you are likely to stain the wood, you will need to use a two pack floor lacquer like :

Carver Omeg-Art Floor Lacquer (outstanding natural looking sealer)

Tover Idrolak DR 97 Floor Lacquer (thick composition water based floor lacquer)

Bona Traffic HD Floor Lacquer (eco water based floor lacquer)

If you are unlikely to stain your wooden floors with an oil wood stain, then you can use a single pack water based floor lacquer like :

Carver Delta Floor Lacquer (the most durable commercial floor lacquer ever)

Tover Uniqua SQ Floor Lacquer (deep penetrating self linking technology)

Bona Mega One Floor Lacquer (no primer needed floor lacquer)

The two pack floor lacquers are not more durable than the single pack at all. The only difference between single pack floor lacquers and two pack floor lacquers is the fact that the two pack floor lacquers are sold with a hardener that makes the lacquer compatible with oil based wood stains. Other than that, there is no difference between single & two pack floor lacquers. 

What is floor sanding? How Do You Apply Sealers?

If your floor was sanded nicely and if you are ready for sealing, we recommend you vacuum the floor well and if you have one available use a fine microfiber flat mop head to extract even the finest grain of dust. If you are planning to stain the floor, now is a good time. Using a towel cloth apply a thin coat of wood stain all over the floor. Apply enough pressure to stain the whole floor evenly. Areas that look a bit too dark or too patchy, can be repaired by scrubbing it a bit more with the cloth. Depending on what brand and type of stain you have used, the drying period can be anywhere between 2 to 8 hours. Read the manufacturers guidelines.

After the floor is dry and evenly stained, you will need to seal it with 2-3 coats of floor lacquer. Remember, the wood stain provides 0 protection, and is only a colour. If the floor was sealed with an oil based wood stain you will need to use a two pack water based floor lacquer or  a solvent based floor lacquer. Mix up the hardener with the lacquer in a separate container and do not touch it for 10 minutes.  1L of floor lacquer will cover about 10-12 sq meters of floor. So if you are planning to lacquer 20 sq meters of floor you will need to mix up 2.5L of floor lacquer with half of the bottle of hardener. That amount will give you enough lacquer for one thick coat. 2-3 hours later you will need to sand the floor again with fine sanding paper, vacuum and apply 1 more coat of lacquer. Same mixture as before.

If you are not staining the floor then you can use a single pack floor lacquer and a primer. Apply the primer undiluted. Allow 2-3 hours to dry. Light sanding to remove imperfections and rough areas. Apply 2 coats of floor lacquer with 2-3 hours break between the coats. 

You can also oil the floor. If you plan to change the colour of the floor you can apply 1 coat of colour oil first and then 1 coat of clear hardwax oil. Floor oils take longer to dry so you will need to wait 24 hours before applying the second coat. 

***all waxed and oiled floors will require regular refreshing and cleaning with proper oiled floor cleaning products***

What is floor sanding? Cleaning & maintenance

The new water based floor lacquers and the new hardwax floor oils are likely to require more specialised maintenance and proper wood floor cleaning products. By using a proper oiled floor cleaner for your oiled floors (Carver Deterol, Carver Dergos, Tover Deteroil, Bona Oiled Floor Cleaner, Bona Soap Cleaner) you will extend the life of your floors while enhancing the protection. By cleaning your lacquered wooden floors with premium quality wood floor cleaners (Tover Pulito, Carver Net Parquet, Carver Deter Parquet, Bona Wood Floor Cleaner, Bona Cleaner) you prevent the floor from scratching and getting water damage.

Remember, water and wood do not make a good home. Try to use as little water as possible and the most suitable cleaning products for your particular type of finish. You can also use a ready to use spray mop like Bona Wood Floor Spray Mop, Bona Oiled Floor Spray Mop or Bona Stone, Tile & Laminate Spray Mop. All you need to clean your floors daily for about 1 month.

What is floor sanding?

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