Seasonal gaps in wood flooring- can it be repaired

Seasonal gaps in wood flooring- can it be repaired

Seasonal gaps in wood flooring- can it be repaired?

Q. We bought our first house last spring, a 70-year-old two story, in an older neighborhood. Since we moved in we’ve been trying to do some things around the house to fix it up, painting mostly, but now we’re ready for some more ambitious projects. One area we’d like to tackle next is the wood floors on the first floor, which we were told are made of oak. One problem is that the spaces between boards seem to be opening up, getting wider. We never noticed this in the summer but in the winter some of the gaps are so big you could put a quarter between boards. Also, on some of the boards, it looks like a piece broke off along the seam. My father in law says we can just fill up the gaps with some wood putty, sand the floor, and then put on some stain to finish them. How hard is this job? Would we be able to do it ourselves? And what kind of stain would you recommend we use to finish the floor? K.M. Grand Rapids.

A. I hate to be the bearer of bad tidings, but it sounds as though your floor may have an intractable problem. This has nothing to do with the gaps you’re seeing between the strips of flooring; they’re perfectly normal, and expected. Wood is a material that absorbs moisture from the air in periods of high humidity, and gives up moisture to the air in periods of low humidity. As it does so, the cells in the wood either expand or shrink. This seasonal swelling (in summer) and contraction (in winter) is most noticeable in homes without good humidity control. By that I mean air conditioning in the summer (which removes some humidity from the air) and humidification in the winter (which puts moisture into the dry winter air). Lacking such governance, homes with large humidity swings between the seasons tend to have wood floors, framing, and wood trim that expand and contract quite a bit. This can lead to gaps in the flooring, as you’re experiencing, and cracked joints between wood trim and drywall or plaster. Again, all of this is normal and expected. There is no harm being done to your floor, and it will swell up tight again in the summer — as it has been doing for the last 70 years.

Putting wood filler or putty down into the seams of a wood floor in order to fill up the seasonal cracks is (I’m sorry to have to contradict your father in law on this subject) a very bad idea. It won’t work, and it will look terrible. There is no putty in the world that can keep up with the expansion and contraction of a wood floor. Subsequently, anything you put between seams now will be squashed when the floor swells back up again in the spring, and it will crack and fall out. In addition, most wood putties do not take stain very well and your floor would wind up looking striped — and exactly like someone forced putty down into the seams. Very unattractive. And that would even be before it all started to fall apart.

Seasonal gaps in wood flooring- can it be repaired

But the real news here is that you probably won’t be able to sand the floor again to refinish it. The fact that you have some broken areas along the joints is a bad sign; it’s evidence of a floor that has already been sanded too many times. The joint between individual strips of flooring — the mechanical connection that holds the floor down and the pieces in close proximity — is called a tongue and groove joint. The «tongue» on one edge of a flooring strip fits into a «groove» milled into the opposite edge of the adjacent piece. When the floor is new there is between 1/4 and 5/16 of solid wood on the top of the groove part of the joint. As the floor gets sanded down time and again the wood gets ground away, and the once thick top section of the groove part of the joints thins. As it nears 1/16 of an inch, any weight on top of the joint, like moving furniture or even walking on it, can cause the wood to break off in thin strips, exposing the inner part of the tongue and groove joint. When that occurs the floor is at the end of its service life. More of the joints will start to break, creating splinters in the floor as well as an uneven and unsightly surface. So your floor, as it is now, can’t be sanded again without causing even more of this type of damage. In fact, if you’re interested in keeping wood floors in your house, you might have to look into replacing the flooring completely — an expensive and messy procedure. What many people do when faced with this dilemma is simply to cover everything with carpet.

To answer your questions about staining the floor (although this would seem moot at this point), stain is not finish. If you were interested in protecting a wood floor from dirt, moisture, and abrasion, you’d likely need some type of film finish like water based or oil based polyurethane varnish.


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