While humidity may affect your hardwood floor permanent cracking is also a possible issue.
How to repair hardwood floors gaps.
Once the filler has dried you can sand and complete the filling process by stain where needed.
The problem is magnified when the boards were not tightly laid in the first place.
In cases where the gaps aren t repaired by increasing the humidity levels you will need to fill these cracks.
Apply filler liberally with either your fingers or a putty knife allowing for some overfill.
Some finishes may also help reduce the risk of your hardwood floor drying.
Repairing permanent floor cracks photo credit.
Water logged wood will first swell then shrink as it dries out.
3 steps to fix hardwood floor gaps.
With older tongue and groove hardwood or even wide plank floors gaps inevitably develop between the boards mostly because the wood shrinks over time as it dries out and loses moisture content.