Oak Floors - When NOT to use fillers
Shrinkage of oak floors usually occurs when interior temperatures rise and oak flooring boards lose moisture. And when the boards lose moisture, they contract, leaving gaps in-between individual boards or between groups or panels of flooring boards. However ...
Shrinkage of oak floors does not always happen due to drier interiors
In newer constructions, a number of factors can cause stretching of the floor, thus causing gaps in between the flooring boards. Some of these factors may be
Settlement of the foundation - When outside walls settle, the area of the floor increases as the floor stretches. When this happens, gaps can develop between flooring boards. By checking the levelness of the floor this can be detected.
Movement of the sub floor - When a building is still under construction, sub floor materials usually remain exposed to the elements for a long duration of time. When this happens, the materials may either expand due to absorption of moisture or shrink with the increase in dryness. This may cause gaps to develop between flooring boards.
Using fillers may not be the most effective solution to gaps caused by factors like these.
But that's not all ...
Fillers are not recommended for use in gaps more than 3/32"
According to NOFMA ( www.nofma.org), wood fillers are not effective for gaps that are larger than 3/32", as they may crack and lead to an uneven finish.
Also, the wood fillers have to be used only when the moisture content of the floor is at its median.
And since the causes of shrinkage will have to be understood before trying to address it, experience and expertise in caring for oak floors
may be essential, and using a cookie cutter approach like using a filler to cover the gaps may not always be the best.