While painted floorboards can look stunning, they’re not generally as practical as varnished or stained boards because paint is more likely to show up dirt and marks.
It can also get chipped, which is annoying unless you like the shabby-chic look.
However, painting boards is easy to do yourself and the end result outweighs any negatives.
Period floorboards often have modern boards mixed in where repairs have been done over the years, and painting them makes it easier to disguise the new ones than with stain or varnish, although there may be a difference in the wood grain.
If the boards are in good condition, you should just be able to use a wood scraper and sandpaper or handheld electric sander to clean them off and make them smooth.
Remember to bang down any protruding nails with a nail punch and hammer, and remove staples or other remnants of the previous floor covering.
After sanding and scraping the boards, clean them thoroughly with a vacuum cleaner and if they’re still dusty, wipe them over with methylated spirits.
If you leave dust and debris on them, it will spoil the finish, so clean them thoroughly first and also between coats of paint, if necessary.
Dust and debris will have gathered in the gaps between the boards too. To clean them out, run a butter knife down them. Alternatively, use a powerful vacuum cleaner, which will do the job quickly and easily for you.
If the boards are in such a bad state that only sanding with an industrial floor sander will do, this is much more of a mission.
Hiring a sander (and an edger) isn’t particularly expensive, but it’s hot, hard and dusty work and you may feel that once you’ve gone to all that effort, it’s a shame to cover the newly sanded boards with paint.
Assuming you are painting them, a quick-drying floor paint, especially a water-based one, is ideal if you need to use the room again soon.
If you can close the door and wait a few days, a solvent-based paint may be better. While it’s certainly recommended to use a specialist floor paint, you could use ordinary wood paint and protect it with clear (non-yellowing) varnish.
However, bear in mind that the paint’s not designed to be walked on, so while it might be a cheaper option, it could be a false economy in the long run.