Brickman Consulting

Wood Flooring Solutions.

What Causes Cupping in Wood Floors?

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Cross posted from Howard Brickman's article on Hardwood Floors Magazine: Inspector Blog.

The official topic of this blog will be an excruciating discussion of the term “cupping” for your consideration. But first…

My apologies for taking so long to get another submission ready, but for me writing is very hard work and extremely time consuming, and I marvel at those gifted individuals who can churn out wonderful written content on a regular schedule. I must admit that I’m not certain that I would be able to increase my output even if I were offered bushel baskets of legal tender to do it on a full-time basis. Time is finite and moves at an increasingly rapid pace. I remember watching the classroom clock as a youngster on Friday afternoons thinking that 4 o’clock would never arrive, and now Friday afternoons pass by faster than the pickets on a fence. But I digress…

If I were going to give an official definition for cupping it would be, “boards that are concave on the face.” There is a common misconception in the wood flooring bidness that all cupping is moisture-related and that pressure that develops due to swelling is the primary cause. Let’s explore some thought experiments.

Experiment 1: We place 10 S4S red oak boards ¾” x 4” x 72” edge-to-edge, which approximates a panel ¾” x 40” x 72”. Then we place pipe clamps at 3” intervals across the 40” dimension and tighten the clamps until a pressure of 200 pounds per square inch is reached. What do you think is going to happen to the shape of the individual boards?

Experiment 2: We place 10 pieces of red oak flooring ¾” x 4” x 72” edge-to-edge, which approximates a panel ¾” x 40” x 72”. Then we place pipe clamps at 3” intervals across the 40” dimension and tighten the clamps until a pressure of 200 pounds per square inch is reached. What do you think is going to happen to the shape of the individual boards?

Experiment 3: We nail 10 pieces of red oak flooring ¾” x 4” x 72” at a MC of 6-8% to a ¾”-thick plywood panel 48” x 72” at a MC of 6-8%. Then we place 1½” deck screws at 3” intervals into the first and the last boards so that they will be prevented from moving. We predrill the oak so that there will be no splitting. Then we place a bath towel on the face of the boards and saturate it with enough water to completely wet the towel but not have water puddling onto the surface of the flooring. Then we put a piece of 6-mil polyethylene over the towel to keep the water from evaporating. What do you think is going to happen to the shape of the individual boards?
 
Experiment 4: We nail 10 pieces of red oak flooring ¾” x 4” x 72” at a MC of 6-8% to a ¾”-thick plywood panel 48” x 72” at a MC of 14%-16%. Then we place 1½” deck screws at 3” intervals into the first and the last boards so that they will be prevented from moving. We predrill the oak so that there will be no splitting. Then we put a piece of 6-mil polyethylene covering the underside of the plywood to keep the water from evaporating. What do you think is going to happen to the shape of the individual boards?

Experiment 5: We nail 10 pieces of red oak flooring ¾” x 4” x 72” at a MC of 14-16% to a ¾”-thick plywood panel 48” x 72” at a MC of 6-8%. Then we place 1½” deck screws at 3” intervals into the first and the last boards so that they will be prevented from moving. We predrill the oak so that there will be no splitting. Then we put a piece of 6-mil polyethylene covering the underside of the plywood to keep the water from evaporating. What do you think is going to happen to the shape of the individual boards?

Experiment 6: We nail 10 pieces of red oak flooring ¾” x 4” x 72” at a MC of 14-16% to a ¾”-thick plywood panel 48” x 72” at a MC of 14%-16%. Then we place 1½” deck screws at 3” intervals into the first and the last boards so that they will be prevented from moving. We predrill the oak so that there will be no splitting. Then we put a piece of 6-mil polyethylene covering the underside of the plywood to keep the water from evaporating. What do you think is going to happen to the shape of the individual boards?

The great thing about these thought experiments is that we could actually do them. If you had a university or commercial testing company do these for you, it would cost many thousands of dollars. If someone wants to send me $12,479.00, I will do the experiments and send you a report on the results with cool pictures. In my next episode we will start to discuss the individual experiments. I want to thank Don Sgroi for the very thought provoking e-mail, which is the inspiration for what will I think be a very interesting series of blogs.

Dispatch from NWFA Prefinished School in the Big Apple

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Cross posted from Howard Brickman's article on Hardwood Floors Magazine: Inspector Blog.

I just attended a three-day NWFA class on the installation of prefinished flooring in New York City. These classes can be a lot of fun and a great learning experience. Most of us work in a vacuum. By that I mean we work within our own little groups of personal and professional associations. There is a tendency to decide that there is one way to do the work, and those habits become deeply ingrained. These classes are a wonderful opportunity to meet new people, learn some new things, experiment with new techniques, and try some different equipment and tools away from our normal cast of characters. We can also make mistakes without any bad financial outcome. The major limitation is the short time horizon.

This particular class is the first NWFA hands-on training event that I have attended in the last 10+ years, and it was a great deal of fun, with many learning opportunities. Daniel Boone (a real wood flooring contractor from Jacksonville, Fla.) was the lead instructor. If you have never been to one of Daniel’s schools, you owe it to yourself to do it at least once. The corny jokes and skills that Daniel uses don’t get old. As charismatic and skilled as Daniel is, the real star of this event was the host, The New York District Council of Carpenters, Labor Technical College’s floor covering instructor, Ron Zimmerman.

This is the Carpenters’ Union training school in New York City, which is a permanent facility that is similar in size to the typical urban community college. But the similarity ends at the front door. Ron Zimmerman runs the Floor Covering Department, which has jurisdiction over wood floors. There are classrooms, demonstration and work areas dedicated to the installation of wood floors. For union carpenters who want to learn the skills required to work for wood flooring contractors, training is available that is structured to teach the skills and tools of the trade for wood flooring. Knowledge and hands-on is a powerful combination. But we all know that you don’t have a relationship with an organization. It is the people who answer the phone, do the work, and make things happen that we have to deal with.

Ron provides a great deal of support to run these classes in NYC in a manner that is comparable with the training provided in St. Louis at NWFA headquarters, although on a slightly smaller scale. This training partnership between NWFA and The United Brotherhood of Carpenters and Joiners of America is delivering a high-quality learning environment for anyone willing to take advantage of the opportunity. There is another class scheduled for August 3-5, with a few spaces still available, so be there or be square.