Furniture, Wood and Cabinetry Finishing - Hardwood floor shrinkage and expansion

I have had two floor refinisher tell me two different things regarding shrinking and expansion.

One tells me he can putty the end gaps, since the boards dont shrink in that direction, they shrink/expand in the width off the board.

Then

I have another floor refinisher tell me because of the way the wood is cut, it will shrink in the butt end and NOT the width, so they can fill the width.

Seems one has to be wrong and in the summer I will end up with Putty popping out if I go with the wrong one.


Help!!

a board will shrink the MOST in the width of the board although there will be some shrinkaage in all directions. Typically one does not fill the area around a wood floor but uses cove base or kick mouldings to cover the intentioanl gap.

The end shrinkage would be fairly minimal but in any case, the moisture content of the wood and the relative humidity of the room would affect how much the wood shrinks. Since humidity levels are always changing, the floor is always shrinking/expanding because of that.

The around the board gap, I was refering to was from board to board, there are sometimes a gap, in the room itself not along the walls.

The humdity now in the winter is 20-30% in the summer it will be 80%+ often

Sorry to hear of your problem. That is why it is important to allow the boards to acclimate to the environment before installation and to control humidity levels after that. (with artifiacial means)

my fathers oak floor has been down for over 35 years and there is nary a crack or gap. The flooring in the new farmers market (http://www.midwestfarmersmarket.com/) has been down for less than 6 months and there are gaps nearly 1/4 inch due to installing damp wood.

but anyway, a board swells or shrinks more in the width of it. If you do not control the humidity, I wouldn't suggest filling any gaps since the boards will continually expand and contract.

If you're refinishing it must be an established floor. If your getting gaps between the boards it must be solid, single strips, T&G. Therefore, nails/staples in each board are holding each one in place rather than letting the whole floor expand and contract together. As stated before, the wood was probably not acclimatized.
If you need to refinish, for cosmetics or otherwise... I would have them sand it, fill it only if theirs holes, then finish it. This isn't ideal, the finish will fill some of the gaps. Have them do it in the summer when the humidity is at its highest (the boards are expanded).
After that you'll need to control humidity to around 50%. Humidify in the winter, dehumidify in the summer. This will also help your heating / cooling bills.
Anyway, thats what I'd do.
JC