Solid Wood Flooring
The standard of the industry is typically a strip flooring product that is ¾” thick and either 2 ¼” or 3 ¼” wide. The standard widths for strip flooring are: 1 ½”, 2”, 2 ¼”, 3”, and 3 ¼”. Wider widths are considered plank flooring and are generally made in one-inch increments from 4” to 8”. Some manufacturers offer other widths such as 4 ¼” and 5 ¼”. These and other widths are generally considered special order. Standard SPIB pine flooring is also different and is generally manufactured on one inch increments plus 1/8”, i.e. 5 1/8” face width. Solid wood flooring can be represented in many ways, sometimes as the actual sizes or as a nominal dimension. For instance standard 1/2” thick flooring is not really ½” thick, but 15/32” thick.
A frequent item concerning solid wood flooring is how to figure how much flooring is needed. Most flooring today is marketed by the square foot as a face width dimension for coverage. However, you may find that some flooring is sold by the board foot. For flooring, a board foot represents the actual size of the blank that is molded to the finished shape, i.e. 2 ¼” flooring is represented as made from a 1” by 3” blank or 3 ¼” flooring from a 1” by 4” blank. The conversion factor for square foot to board foot is different for these two products. For 2 ¼” flooring it is-- 3 divided by 2.25 or 1.333, and for 3 ¼” flooring it is-- 4 divided by 3.25 or 1.24. Other ¾” thick products are figured in a similar way with the blank as ¾” wider than the actual face width.
Another factor that confuses is the end matching allowance for solid wood. Since solid flooring is considered random in length, it is very difficult to measure the lengths of every piece to determine the exact coverage of the flooring pieces. Since the beginning, the end match or end forming, normally considered ¾”, is included as part of the actual length of mass produced flooring. In other words, a 36” long piece of flooring is counted as 36.75” long. With any installation there will be field cuts made and some waste. The standard cutting allowance for square and rectangular rooms is considered to be 5% of the overall coverage area. This 5% has traditionally included the allowance for end matching. An example-a room 18’ by 27’= 486 square feet, flooring required would be 511 square feet rounded up to the nearest foot or bundle. This 5% should be used where the average length of flooring is 2 ¾’ (33”) and longer. As you can see with shorter flooring more pieces are required, more pieces mean more end match allowance which takes up a greater part of the cutting allowance. So, with shorter average lengths, a greater cutting allowance is required. A general rule of thumb is 6% to 7% for lengths averaging 27” to 32”; 7% to 10% for lengths averaging 24”; and a minimum 10% for “1 ¼’ shorts” which average 18”.
One other question that is asked is how to determine how much flooring is needed when different widths are involved such as a random plank floor with widths 3”, 4”, and 6”. If the installation is a repetitive pattern the object is to order equal lineal footage. I will typically add the widths, in this case they equal 13, and then convert each width to a percentage; 3” equals 3/13 or 24%; 4” equals 4/13 or 31% and 6” equals 46%. For a 1,000-square-foot floor, the order will be; 3” flooring-240 + 12 (5% cutting allowance) = 252 square feet; 4”flooring-310 + 16 = 326 square feet; and 6” flooring-460 + 23 = 483 square feet.
There are a number of other sizes of solid wood than ¾” thick flooring. Other standard thicknesses are: nominal ½”-15/32” actual; 3/8”-11/32” actual, and 5/16”-5/16” actual. These sizes are generally considered thinner flooring and have different requirements for subflooring and nails/cleats/staples than ¾” and thicker products. The classification for thicker flooring includes the standard thicknesses- ¾”, 25/32” (MFMA standard, NOFMA allows maple products to be manufactured in this thickness), and 33/32” (MFMA standard).
There is basically no difference between unfinished flooring and factory-finished flooring regarding measurement and dimensional performance except that finish delays acclimation and factory finished flooring is normally boxed. It’s difficult to see in the box, so monitoring the amount of flooring in the box can be difficult. Will every box have the same and correct amount? Likely they will be very close, but the amounts in 20 boxes should average the stated amount.
Engineered flooring is quite different from solid wood. Neither the HPVA ANSI standard nor NOFMA Official Flooring Grading Rules list any standard width or thickness for engineered flooring. Some common thicknesses are 3/8”, 7/16”, ½”, 9/16”, and ¾”. Widths are mostly on the inch measurement. The construction can be any number of plies, dimension parts, or composite materials, as long as the construction is balanced and does not introduce warp or twist.
Engineered flooring measurement is more straightforward than solid wood. Much of engineered flooring is not random in length and thus can be more accurately measured. Even when different lengths are boxed there are often only 3 to 5 length variations. Since the random component is eliminated, the stated square footage can be placed in each box.
A major classification for engineered flooring is the manufacturing technique used to produce the wear layer. One common technique is to rotary peel the veneer. This produces a uniformly tangential grain orientation. Most every piece of a rotary product will have the wide cathedral or flame pattern look. Sliced veneers have a more random look with different grain orientations. There can be pieces with the quartered look to pieces with plain sawn features. Another type is the sawn veneer. This is essentially a thin flat piece of dimensioned wood that is adhered to a plywood or composite core. A sawn veneer is likely the thickest of the available wear layers. Further, the thicker the wear layer, the more similar to solid wood will engineered flooring perform.
As a wood flooring category, engineered flooring performs differently than solid wood. One primary aspect is dimensional change. Engineered flooring is influenced by its construction. The cross banding restrains the potential dimensional change in width so that seasonally little side gapping or cupping is noted. The other dimension, length, is a different story. The cross banding also introduces the width component along the length. Engineered flooring can change in length 2 to 5 times as much as solid wood in equal settings so that seasonal gapping at ends is noticeable.
Here we have discussed the two primary categories of wood flooring, engineered and solid. Each category has some of its own unique issues. There can be many subcategories but even the subcategories will perform similarly to the primary category. Remember to read and follow manufacturer’s directions and industry recommendations from the different governing associations. Make a habit of checking the products BEFORE they are installed. Also, to protect yourself, promptly advise the distribution chain if any abnormal issue arises.