Floor Sanding – What is all about
You may have heard the term “floor sanding” and like most people who are not DIY specialists, you may not know exactly what it is. Ok, let`s explain it to you.
Floor sanding usually refers to wood floor sanding. Other surfaces can be sanded with more or less the same equipment, but in general when people are talking about floor sanding, they are likely to be referring to wood. There are many types of wood floors and most of them are finished with a sealant. You can use many types of sealants, I will explain more below. All these sealants, over time, will wear off and the wood surface that used to be protected, is not protected anymore. As a result, water damage will appear. Black stains from mopping, dirt deposits in the grain of the wood & patches. Areas with more traffic will wear off more than areas with less traffic. This is why in some places, the hallway or the kitchen area show signs of damage and discolouration, while the living room area is near perfect.
Floor sanding refers to the operation of removing all the old sealants and refinishing the wood. That is it.
Floor Sanding – How is it done
There are many techniques and many types of machines. Depending on who does it, yourself or a professional floor sanding contractor, a standard floor sanding for a living room could take a few hours or a few days. There are 4 types of floor sanding systems:
Orbital Sanders (buffers)
If you are a complete amateur, you should probably use an orbital sander or a plate sander. It will take a bit longer but there is less risk of damaging the floor.
Orbital Sander – this is the best way to sand small areas of floors relatively risk free. A sanding screen will be used to remove all pre-existing finishes. Starting from grit 40 up to 120. The 40 grit will remove all types of varnishes, hardwax oils & sealants. The 60 grit will level up the scratches created by the 40 grit and the 80 grit will create a perfect smooth surface ready for sealing. In some cases 24 or 36 grit sandpaper has to be used to remove paints and uneven surfaces.
Plate Sanders – not as popular as they used to be but some people still use them. The plate sanders are easy to use, the square shaped makes it fit easily intol corners and they are not too heavy. The same process of changing sandpaper by grit will apply. If you have the time and if you don`t mind a lot of dust, floor sanding with a plate sander is for you.
Drum Sanders – these are more for the professional floor sander. Many professional floor sanding contractors still use drum sanders. A belt will roll a drum at high speed and the drum will be dropped onto the floor slowly. This floor sanding technique is pretty risky if you don`t know what you are doing. You will cover a bigger area faster but you can sand up some big holes in the floor. The drum has to be managed to perfection to achieve perfect results. You can start from 24 grit up to 80 grit sheets. The sheets of sandpaper can be changed very easily by unscrewing a steel holder.
Belt Floor Sander – this is what all proper floor sanding contractors use. Belt sanders are very powerful, very heavy and very efficient, A belt sander can do 50 sq meters of floor per hour. It varies from size to size and from brand to brand but nothing provides quicker and better results than a belt sander. It should not be used by people that have never done floor sanding before. The belts can be easily changed by pressing a handle.
Now you know what people use to sand wood floors. But how is it done?
On a wood floor there can be a wide a range of finishes. Some people use solvent based varnishes, others use hardwax oils, other polishes, other floor paints, etc. You will need to remove all these finishes to reach the wood. Depending on what is on your floor, you will need to pick the most suitable sandpaper.
If the floor has no paint on it, you should start with 40 grit. Sand the whole floor going with the fibre of the wood, not against. The edges will have to be done with a small edger or a small orbital. Professional floor sanding companies will have powerful edgers that can go 2 mm from the skirting.
After the room looks perfectly even, you need to go with 60 grit sandpaper. Same process. Then 80 grit paper. By now the floor should look perfectly flat and even. You are ready for sealing the floor. The bare wood is like a sponge, it will absorb all the water and spillages. Be very careful not to spill anything.
The next process is sealing.
Floor Sanding – Sealants & Stains
If you are happy with the way your floor looks naturally, you can use a primer and a clear water based floor varnish. If you need a “peachy” finish or a slightly warmer finish, you can use a solvent primer and a water based floor lacquer over it. If you are planning a big change of colour, you can go for a stain or a floor paint.
Water Based Floor Lacquers – most people who got their floors done in the early 90s, know how smelly solvent based floor sealers are. These people also know that solvent based floor lacquers react with UV light and change colour. Some nice white pine floors end up looking deep yellow. Well, these problems are non-existent if you use a water based floor lacquer. Water based floor lacquers dry almost instantly, they are usually fully dry in less than 1 hour and will never react with UV light. Your floor will never turn up yellow over time.
Just because a product is called water based, it does not mean that it will wash away easily or it will not last. That is not the case at all. The water based term comes from the process of manufacturing it. Old solvent based varnishes were manufactured from oil extracts while new water based floor lacquers are manufactured from non oil products. That is the only difference.
Single Pack Water Based Floor Lacquer
Two Pack Water Based Floor Lacquers
There are two types of water based floor lacquers. Single pack and two pack. Initially, the single pack floor lacquer was only suitable for domestic traffic while two pack was used for commercial floors. Two pack means that the varnish is sold with a hardener that makes it more durable and compatible with oily primers or wood stains. This is not the case anymore. Single pack water based floor lacquers are as strong, if not stronger, than two pack varnishes. Not all of them, but some. There are many two pack floor lacquers much less durable than single pack.
The main difference now is that two pack floor lacquers are suitable for overcoating wood stains. Tover Uniqua Floor Lacquer – single pack is much more durable than Tover Idrolak DR 97 Two Pack Floor Lacquer.
So if your floor sanding contractor is using single pack floor lacquer, you have no reason to worry.
Solvent Based Floor Lacquers – even if it takes a lot of time to dry and it smells for days, some people still use solvent based floor lacquers. Solvent based floor lacquers are thick and creamy. It glazes the floor nicely and it provides very good protection.
Hardwax Oils – hardwax oils are not as popular as they used to be. For thousands of years people have used animal fat and organic oils to waterproof wood floors. Over the past few years, as the water based floor lacquers got better, people are re-considering oils. You can achieve the same natural finish with water based floor lacquers and there is no refreshing required. Makes more financial sense. But there are many people still in love with the oil finishes. There are hundreds of colours available, there are low, medium and high traffic finishes and there are hardwax oils.
***all oiled floors require regular refreshing. Once per year at least, the floor has to be re-oiled***
Wood Stains – Floor Sanding
A few years back, to change the colour of your wood floor, you had to either bleach the wood or apply a coloured varnish. The problem with the coloured varnish is the fact that it only glazes the floor 1 mm and if the floor gets scratched, the white wood colour will be very visible. Also, most coloured varnishes look very artificial. All these issues were sorted out when wood stains were invented.
A wood stain is just a colour. You can apply it over any type of wood surface. Some wood floors do not stain well so pre-testing is required. Maple floors do not absorb the stain evenly so if you plan to stain maple floors, you are limited in your options.
The floor has to be sealer free. You can apply 1 or 2 coats of wood stain, depending on how strong you want the colour to be. Bear in mind that a wood stain is only a colour, it has no protective qualities at all. The wood stain will require sealing before use. The wood stain will penetrate the wood and it will even up the colour. You can make pine wood look like oak and yellow floors look white.
2-3 coats of varnish should be applied over the stain. If you are using a water based wood stain and an oil based wood stain, you will need to use a two pack water based floor varnish. Not all wood stains are compatable with all varnishes. If you are using different brands of products, please do a sample test. In some cases the varnish could exfoliate.
Gap Filling – Floor Sanding
Some old floorboards could have a lot of gaps. Some people love it while some people hate it. If the gaps are 0.5 cm or smaller, you can use a gap filler to fill it up. Dust from the floor itself will be used and a solvent or an water based gap filler should be used. The wood dust should be mixed up with the gap filler and then used to fill up the gaps. 2 coats are recommended. The gap filler will dry to look nearly 100% like the floorboards. You can stain and varnish the gap filler.
People fill up the gaps between the floorboards for a few reasons
Insulation – draught can be a problem in old houses. If you fill up the gaps between the floorboards, you will prevent draught
Look – some people just hate the look of the gaps (other loves it)
Cleaning – dirt & hair falls between the gaps so for some people not being able to remove it is not ideal. Filling up the gaps, will prevent dirt depositing under your floorboards
Dustless Floor Sanding – Floor Sanding
In 2020 you should expect to have your floor sanded with dustless floor sanding technology but this is not the case all the time. Many old floor sanding companies still prefer to use the old types of floor sanding equipment.
There are machines with no system of extracting the dust, there are machines with some kind of extraction system but not in full and there are machines that extract over 98% of the dust generated. In other words, you could get your floors done without having to vacuum for weeks after the job was completed. If you are doing just a small bedroom or any other tiny room, it doesn`t matter what type of system is used. But when you do a large commercial floor or a floor in a big shopping centre, collecting 90% of the dust generated could be a deal breaker.
Floor Painting – Floor Sanding
There are many types of water based and solvent based wood floor paints. Usually, a wood floor should be painted to facilitate easy maintenance or in cases where the wood is too damaged to look well with a varnish coat. Our company uses Tover Uniqua Wood Paint – available in 12 colours. When you paint a wood floor, you lose the warm look of wood. The floor will look artificial. If you do not mind that look, a paint is the sealant for you.