how to extreme

Installing Prefinished Hardwood Floors

Construction How-To, Flooring Installation, Floors, Hardwood, Projects September 23, 2015 Sonia









By Larry Walton

Photos by Tim Walton

My wife and I love hardwood floors but we do not love living in a remodel while we’re installing or refinishing hardwood floors. We know this because we’ve done it a number of times.

One of the big advantages of full-thickness hardwood floors is the option of sanding and refinishing the floors in the future if the floor gets damaged, which is likely with me and my dogs.

We wanted a traditional 3/4-in. thick tongue-and-groove hardwood floor without all of the sand-in-place dust and the added hassles that come with applying the finish. We found some prefinished maple flooring at the local home-improvement center that looked like it would work well for our application. We have now had these floors in our house for a couple of years, and they’re performing better than we expected.

From a woodworker’s perspective, I knew that this flooring would have to fit tightly and flat to work, because “prefinished” meant no possibility of floating and sanding the gaps and elevation differences like traditional unfinished hardwood floor. The manufacturer did several things to pull this off.

First, they made the boards relatively narrow which helps the installer pull slight curves in line. It’s likely they took extra care in cutting any curved materials into shorter pieces to make them all as straight as possible.

Next, the manufacturer kept very precise tolerances for board thickness and for milling the tongue-and-groove profiles. We could tell this because the boards laid up to a very flat surface when installed. This is noticeable to someone who has installed raw hardwood and encountered the occasional slightly thicker or thinner board. Normally these discrepancies can be sanded out of traditional hardwood, but prefinished boards must match up better because they cannot be sanded flat.

It is wood, however, which is why they included a slight chamfer along the edges of the boards. The purpose of the chamfer is to accentuate rather than hide the joints. This feature covers up slight discrepancies in the board thickness and any small gaps where the boards join.

Another aspect unique to prefinished hardwood is the need for colored putty to fill holes where the boards cannot be blind-nailed through the tongue. We mixed different colors of putty together to create several shades so we could match exactly the color right where the nail hole was.

One of the big advantages of 3/4-in. hardwood is that it has enough structural integrity to bridge over small cracks and holes in the subfloor. (You must still make sure that moisture cannot get to your new floor.)

When starting the first row of flooring, make sure you are square with other important features in the room. In our case, the first room we installed was pretty forgiving because of the perimeter features, but this floor would eventually tie into the hallway, and the hardwood there needed to be in line with the walls. Because of this, we used a string line centered in the hallway to determine the alignment in our first room.