Hardwood Flooring
DEAR TIM: I have a hardwood floor in my home that is approximately six years old. Late each winter, tiny cracks appear between many of the boards. These cracks seem to disappear each summer. Also, I recently hosted a party. The narrow high heeled shoes one of my guests wore created depressions in the wood. Did I get a bad batch of wood? C.K.
DEAR C.K.: I don't think you are going to like my answer. My intuition tells me that your wood flooring is not defective. Your hardwood flooring is responding to seasonal swings in the relative humidity of the air.
Wood is a very interesting building material. It is hygroscopic. This means that when exposed to air, it will pick up or release moisture until it is in equilibrium to the current relative humidity. Anyone who owns white painted cabinetry or paneled doors has probably witnessed this phenomenon. The mitered corners of painted cabinets will develop hair line cracks. Door panels will crack the paint where they fit between the stiles and rails of a door.
To make matters worse, wood does not expand or contract equally in all directions. It moves the least along the grain of a piece of wood. It expands or contracts the greatest amount across the grain of the wood in a direction parallel to the growth rings. It just so happens that a majority of wood is sawn in this fashion. This method of sawing produces the least amount of waste from a log. Dimensional changes of 5 - 15 percent are not out of the question.
CLICK this image and listen to the first call on the podcast. I talked to Jill about how to repair wood kitchen flooring, and possibly installing an inlay border as an option. Copyright 2018 Tim Carter
What do these numbers mean to your oak strip flooring? Some areas of the nation see significant changes in relative humidity from winter to summer. In your state, Minnesota, the moisture content of your hardwood floor can range from 5 percent in the winter months to 10 percent in the summer. That fluctuation in moisture content will cause a single two and one-quarter inch piece of oak flooring to shrink or swell 1/32 of an inch, the thickness of a worn dime.
Don't be fooled by the high quality layers of finish on your flooring. Most floor finishes do a substandard job of blocking water vapor. Not only that, your wood flooring can absorb moisture from its underside. If you want to eliminate this seasonal movement, you must maintain a constant level of humidity within your home.
Installing a new hardwood floor? Use my Hardwood Flooring Installation / Refinishing Checklist to avoid costly mistakes. I offer a 100% Money Back Guarantee.
The damage that your flooring received from the high heeled guest is very understandable. Hardwood flooring can be damaged by any concentrated pressure in excess of 1,000 pounds per square inch (PSI). If those high heels had a tip of only one-quarter inch and your guest weighed 130 pounds, each step she took exerted more than 2,000 PSI! Your floor would be in excellent shape had you invited elephants to your party. They only exert 75 PSI with each foot fall.
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