Use a long handled roller to spread the varnish first in the same direction as the grain then across.
How to floor varnish.
Depending on the condition of the floor you may need to start sanding with a coarser sandpaper.
Work one manageable area at a time such as four square feet.
Start at one end of the room and sand with the grain.
Instructions and help on how to varnish your wooden floor.
This will ensure that the varnish looks natural.
Let the dust settle vacuum it up and then wipe down your floor with white spirit.
Use less coarse sandpaper usually around a 120 to 150 grit abrasive to get a lovely smooth finish.
When making the strokes try to follow the wood grain.
Apply the stain with a foam applicator pad in the direction of the wood grain.
Fill in any gaps in the floorboards if you need to or want to.
Apply in sections which are no larger than 4 to 5 square feet.
If your old varnish is flaking off use a floor sander to sand back to the bare wood.
Use your brush to apply the new oil based varnish to the floor.
Pour a small amount of varnish onto the floor starting in the corner farthest from the door.