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Random-Width Calculations
How do I figure out exactly how much I need of each width when ordering random-width flooring?
Chuck Coffer, north Georgia territory manager at Charleston, S.C.based William M. Bird & Company, answers:
It is remarkably easy to figure out how much material you need for multiple-width jobs, but it seems hardly anyone knows how to do it.
You simply take the sum of the set and use that as the denominator. In the case of a floor with planks that are 3, 4 and 5 inches, the sum of those three widths is 12. All you have to do is figure each width as a portion of that sum, so divide each number by the sum. Once you do that, you find that the 3-inch width is 25 percent of the job, the 4-inch width is 33 percent of the job and the rest is 5-inch (42 percent).
Say you need 800 square feet of flooring. For the 3-inch, you multiply 800 by 0.25 to get 200 feet. For the 4-inch, multiply 800 by 0.33 to get 264. The remainder of the flooring, 336 square feet, is the 5-inch flooring.
Cupping & Painting
A week after I installed, sanded and finished an oak strip floor in a new house, the customer decided to have the entire interior of the house repainted, and the floor cupped. Could the painting have caused the cupping?
Rusty Swindoll, assistant technical training director at the National Wood Flooring Association, answers:
Yes, it could. It may seem like just painting wouldn't bring enough moisture to the job site to make the floor cup, but in this case, with the entire house being painted at once—not just a room here or there—it is possible that the painting made the floor cup.
When you start a job, you need to be aware of everything happening at the job site, not just in the area where you're doing the wood floor. All the wet trades, such as plastering, drywall, painting, masonry and tiling, should be done. I recently had a call from a contractor who had installed a solid prefinished floor that cupped not long after installation. As we talked, he mentioned that the basement wasn't poured until after he installed the floor. This allowed all moisture vapors from the concrete to rise up to the subfloor, increasing the moisture content in the wood flooring. You need to check the basement or crawlspace on every job.
It isn't just the inside of the job that you need to check, either. Take a look outside to see the grading of the lot and the plantings around the house, and ask if the landscaping is complete. In my contracting days, I had a job on a concrete slab where we installed a solid, site-finished floor over a plywood subfloor. The grading of the soil when we did the job was below the level of the slab. We got a call after the floor was done that it was buckling. When I came back to the house, I saw that they had landscaped since I had been there. The soil was now 8 to 10 inches higher than the slab, so my floor was now below-grade, and sprinklers had also been installed next to the house.
When the floor is buckling, you have no choice but to replace the damaged area or remove all the flooring, but if the floor is cupping and it isn't severe, it's possible that when the job site returns to normal moisture levels, the floor will lie back down. So, don't rush to resand the floor—if you sand it before the moisture content has normalized, you'll just end up with a new problem—a crowned floor.
Measuring Below?
When I lay my pinless moisture meter on top of my wood flooring, it is telling me that the moisture in the concrete subfloor is over 13 percent. Does this make sense?
Robert McNamara, director of sales and marketing for the Construction and Distribution Division of Middleton, Mass.-based Bostik Inc., answers:
This issue comes up all the time. For some reason, many installers and inspectors are under the false impression that if they click on the brick/concrete reading on a pinless meter and place it on top of the wood flooring, the meter will read underneath the wood flooring to measure the moisture content (MC) in the concrete below. This is simply false! No moisture meter can read the level of moisture in concrete below an installed floor.
It is important to know how a pinless moisture meter works so that you can understand what it can or cannot do. The only way to accurately measure MC in the concrete below the floor is to remove the flooring first.