I have bought a house build on a slab with assorted size pine planks (boards) for flooring. They apparently were put down green and have shrunk considerably. There is no tongue just straight edges. There is about 2 inches between the slab and the boards and things fall between the cracks and it is a good place of insects to hide. I am wondering if there is anything we can put between the boards or can do to give us one smooth floor and not have to rescrew the floors as that will leave us short a few boards when we are finished. No one has come up with anything yet.