Our flooring is a very old wide plank pine. It has shrunk considerably in several areas, leaving long wide gaps. There is no underfloor. This pine was laid right on top of the joists (old farm home)What would you recommend for filling in and/or repairing those wide gaps?
I am afraid that if the floor was not installed by the methods as outlined in the Strip and Plank floor article in the Hardwood Authority section of this site, you will always have a shifting floor. And unless the floor is properly screwed and pegged any filler you choose to put between the gaps will soon crack out.
This is mostly because of the nature of the old farm home. It is may have been kept closed up for long periods, so that the interior experiences wild humidity swings depending on the season. In fact a closed up house can have what they call green house effect, that in a dry climate will bake the wood to desert dryness. But in a wetter climate can make a sweat lodge effect. All when you are not there to do anything about it. I can if you wish, give you some recipes to fill the floors only if you are going to sand and refinish it. And a more detailed instructions on how to screw and peg the floor, so that it doesn’t move nearly as much.
As always your Most humble servant, Joseph, the Wood Floor Doctor.