gaps between the floor boards


Our hardwood floor is about 4 years old (oak),it is a sand in place type. There has developed, or at least became obvious, small openings between a few of the boards. How can these be repaired. I seem to get a lot of different answers. The spaces are about a 16 of an inch wide and vard in length from 2 to 4 inches.

Your help would be appreciated. Thank you.

Walt Murphy


Dear Walt

These are not considered by the industry to a defect in the floor , but a normal seasonal change in the floor. And you will hear that in the Spring the gaps will go away on their own. And while this may be partly true, sometimes too thin subfloor can contribute to the gaping or worse yet the use of OSB as a subfloor. Floors that are stapled have a shifting problem also.

The best thing to do is to wait until spring and do some minor cosmetic filling with a colored latex filler. My favorite is the Le Pages brand at plid=305x=687. But be sure to wipe off all the excess right away with a wet cloth and then a dry one. Else the filler will dry as a messy film on the surface of the wood finish.

But wait. Have you been doing your part in stabilizing the environment this solid wood is in ? You should maintain an indoor humidity level of about 40-60%. And I mean all year round. So, if this was a particularly hot and humid summer in your area, you may have been tempted to throw the doors and windows open, rather than waste energy using the air conditioner. Even floors finished on site are susceptible to these high humid conditions, and will swell up quite a bit. The boards will push against each other, and move into the expansion gaps at the long edges. You will not notice this. The indoor humidity can easily reach 80% for weeks if not months.

But at some point in the Fall we turn the heat on and bake these floors to desert dryness. An un-humidified house can easily reach a 25% level in the middle of winter. These extremes on solid wood will cause the wood to reach an equilibrium moisture content of as high as 14% in the summer and as little as 5% in the dead of winter. And this movement will easily cause the gaps you speak of and worse.

So the answer in the long term is to keep the RANGE of humidity as small as possible. Not more than 20% if you can. Humidify in the winter and air condition or at least dehumidify the basement in the summer. And have the floor re-coated every 5-10 years depending on use. Be sure to read the first part of the cleaning article in the Floored News section of this site. The judicious use of the right cleaning products can help also.

If you found this information helpful, please explore the Wood Floor by visiting the rest of our website.

As always your Most humble servant, Joseph, the Wood Floor Doctor.-