There’s no doubt about it: wide plank flooring can definitely make an impressive design statement. But it also comes with challenges, starting with the natural limitations of various wood species (see Part 1). After you allow for and plan for those limitations, it’s time to consider the necessary differences when it comes to milling and installation; both processes need to be completed in a way that allows for the added issues relating to movement that come with wider-than-usual boards.
Proper Drying for Wide Plank Flooring
All wood moves; we’re guessing that you realize that already. A combination of radial, tangential, and longitudinal movement is typically pretty predictable based on time of year, geographic location, and lumber species. Acclimatization is always key, but there’s definitely more to it than that, when it comes to wide plank flooring.
Wide planks create added challenges, though, in large part because they’re necessarily taken from the cross sections of trees, including the highly volatile central area of a tree, referred to as the pith. This situation is necessary in order to take advantage of the entire diameter of the trunk. Typically, it will mean that each board will have stable edges that have a combination of quarter- and rift-sawn grain; however, each board will also have a far-less-stable central area.
While the quartersawn areas will expand and contract fairly predictably throughout a board’s thickness as the moisture levels change, however, the central areas of the board will only move directly across the width of the board. If you’re visualizing this, you might be picturing something like a hinge; if so, you’d be correct.
The greater the percentage of quartersawn grain that’s included in each plank, of course, the greater the stability of the board will be; however, there’s no way around including some pith area without decreasing the board width. As a result, careful drying is extremely key, as is slow, steady milling. Re-milling also allows for gentle acclimation of the wood.
Proper Milling for Wide Plank Flooring
While normal-width floor boards can be effectively joined with either ship lap or tongue and groove, wide planks are much better joined with the latter method. Essentially, the groove traps the tongue of the adjacent board, preventing lift that would lead to unevenness in the floor. This joint can be modified to allow for some added movement while still keeping the entire floor from getting out of control. By carefully sawing, drying, and milling wide plank boards, you can give your wide plank floor a great chance at being stable despite its tendency toward greater movement.
But the final part of the equation is proper installation, which we’ll discuss in our final post in this series.
