Sanding and varnishing wood floors

Job description:

Restoring tired floorboards can be a great way to rejuvenate a room and provide an easy to clean and maintain floor which also looks visually stunning. Floorboards are also great for allergy sufferers as they do not trap dust and pet hair.

Sanding and varnishing wooden Floorboards

Below we have provided a detailed guide with step-by-step instructions on what work is required to sand back and varnish your floorboards.

Skill level: 2 – intermediate  

What you’ll need:

  • Belt Sander - plus selection of varying grit sandpapers
  • Circular edging sander - plus selection of varying grit sand papers
  • Hand held detailed sander - plus selection of varying grit sand papers
  • Triangular shavehook
  • Hoover
  • Hammer
  • Nail punch
  • Lecol
  • MDF Strips
  • Putty Knife
  • Water based varnish
  • Medium pile roller
  • 2" paint brush
  • Dust mask

Step by step guide to sanding and varnishing wood floors:

1. Clear the room entirely of all objects, seal up any doors or windows where you do not want sawdust to go. Make sure at least one window or door is kept open for ventilation

2. Start sanding using the belt sander with a coarse grit paper. Sand the floor at a 45 degree angle to the boards to level them. Once the whole area has been done use the edging sander with a coarse grit paper to go around the outside of the room (be very careful around radiators and pipes as they can easily get cut, it is best to remove these if possible). Finish off the corners with the triangular shavehook

3. Change to a medium grit paper and repeat the process with the belt sander, this time sanding along the length of the boards. Save the sawdust from this second sanding and put it to one side for later. Do the same with the circular edging sander. If you have areas with a black tar like coating use the edging sander to 'flick' this off, if you press down too hard and for too long it will quickly clog up your sand paper.

4. Next you will need to fill the gaps between the floorboards to stop cold drafts coming through. For larger gaps (more than 5mm) it is best to cut MDF strips to size and gently hammer in to place. For the rest of the gaps mix up the saw dust you saved from the medium grit sanding with Lecol to form a paste. Use the putty knife to carefully work the mixture in to the gaps and smooth level as best as you can. Leave to dry overnight.

5. Sand the floor again with medium grit papers to smooth down the MDF strips and lecol filler. Finally finish the whole area with a fine grit paper. The floor boards should now be smooth to the touch

6. Thoroughly sweep and hoover the entire floor to remove as much sawdust as possible. It is also advisable to wipe down the floors with a damp cloth to pick up as many of the fine particles as possible.

7. Use the medium pile roller to evenly spread out the water based varnished over the floorboards. A lot of this will soak in on the first coat and will require more varnish than further coatings. Remember to work from the furthest point of your exit from the room so you finish by the door you want to leave by. Use the paint brush to do the edges and once completed leave to dry for at least 3 hours.

8. Once dry use the hand held detailed sander to lightly sand the whole floor with a fine grit paper to remover any of the wood fibres which have been raised by the varnish. Hoover again to remove dust and then start the second coat of varnish in the same way as you did the first.

9. It is recommended you do at least 3-4 coats of varnish to get a quality finish. After the last coat do not sand again. Once completed wait 48 hours for the varnish to fully harden before you replace any furniture and do not clean or wet the floor for the first week.  

Care and Maintenance:

Water based varnished floorboards need to be simply swept to remove dust and dirt. They can also be cleaned with warm water and a light cleaner on a damp cloth. Do not over wet the floor. Floorboards will naturally darken over time and heavy use areas may require sanding and re-varnishing after some years of use.    

The information provided in this guide is to be used strictly for guidance only. We recommend you always read the manufacturer's instructions.