International Standards for Unfinished Solid Wood Flooring
THE APPEARANCE OF WOOD DETERMINES ITS GRADE
- Clear wood is a flooring product with minimal character marks that provides a uniform appearance.
- Select wood is a flooring product with natural heartwood/sapwood color variations that also includes knots, streaks, etc.
- Common wood (No. 1 and No. 2) has more natural characteristics such as knots and color variations than either clear or select grades, and often is chosen because of these natural features and the character they bring to a room. No. 1 Common has a varied appearance, light and dark colors, knots, streaks and wormholes. No. 2 Common is rustic in appearance and emphasizes all wood characteristics of the species.
- First Grade Beech, Birch & Hard Maple will have the face practically free of all defects, but the natural color of the wood shall not be consider a defect. The highest standard grade, combines appearance and durability.
- Second Grade Beech, Birch & Hard Maple a floor with varying wood characteristics and colors to include distinct color variations, numerous Streaks, stained Sapwood, sound Knots, and Checks. All defects must readily fill.
- Third Grade Beech, Birch & Hard Maple must be of such character as will lay and give a good serviceable floor. The wood must be firm, Serviceable and may contain all defects common Maple Pieces with 1/4 full Tongue admitted. Third Grade will not admit-Knot Holes over 3/8" in diameter or unsound Knots where the unsound portion is over 1" in diameter; Voids on Ends or Edge; or Shake, Hear Checks, badly Split Ends and Imperfections in Manufacture which would materially impair the serviceability of the floor.
DIFFERENT TYPES OF FLOORING CUTS
Even though all hardwood floors are made from real wood, the properties of each type vary in ways other than the trees’ hardness. The region where the trees grew, the method used to saw the log for flooring and the manner in which it’s dried combine to create a unique floor.
Some like trees harvested from northern forests for their consistent color, and tighter growth rings, due to the slower growing season. They also produce a more desirable end product. The type of flooring cut made into the wood at the sawmill makes a difference in the appearance and quality of the flooring.
The different types of flooring cuts are as follows:
This is the most common type of flooring cut used today. Also known as flat sawn, it involves workers cutting a side of the log and then turning it 90 degrees before the next cut is made. The process continues in the same fashion until they use the entire log. Even though it’s an efficient method of cutting wood, it produces more waste material than live sawn milling.
Graining in plain sawn wood is between 0-30 degrees. As a result, you’ll see large, open patterns on the boards. These are referred to as a “cathedral effect,” since they resemble the steeples of these large places of worship.
Many houses built in the early-to-mid 1900s had both quarter sawn and plain sawn red and white oak floors. The floorboards measured 1-1/2”, 2-1/4” and 3 inches across and for a number of people, this is what “traditional” oak flooring looks like.
The first step in rift sawing wood is to cut it into quarters. Next, the wood is cut radially perpendicular to its growth rings. This type of cut produces grains at angles of 30-60 degrees, with 45 degrees being the most desirable.
It’s the most expensive way to saw wood, and likely for this reason, it’s used the least often. The result of the cuts is a straight grain pattern with discernible flecking. This type of cut has the potential to produce flooring boards of exquisite beauty and extreme stability with a linear appearance that you don’t get with other types of cuts. If you have your heart set on having hardwood in your home with a long, straight grain pattern, you’ll want to look for boards that have been rift sawn. With this type of cut, it’s very difficult to get floorboards wider than four inches and greater across. This type of cut in softwood flooring would be called Vertical Grain.
When a log is being cut for quartered flooring, as the name implies, the first step is the cut it into quarters. Next, it’s cut perpendicular to the growth rings in the log. It produces tight graining at angles of 60-90 degrees, resulting in that are close to the surface of the boards. The resulting pattern is beautiful flecks of color from the wood’s medullary rays (ribbons that extend vertically through the tree, perpendicular to the growth rings).
Quarter sawn milling is more expensive than plain sawn, and this method produces more waste material. Boards sawn using this method are generally narrower than ones cut using the plain sawn method. Red and white oak is generally quarter sawn in order to show off the wood’s distinctive straight, striped grain.
This method of sawing wood for flooring matches the wood grain of Mission-style furniture. If you want to create a coordinated look with your flooring and furniture, you’ll want to keep this detail in mind.
With this method, the log is cut straight through with each pass. Subsequent cuts are parallel to the first one. The yield is a mix of plain, rift and quarter sawn woods; there will be about one-third of each per log. Since all the cuts are straight, this method is virtually waste-free. This method also produces the popular wider boards popular with consumers.
Moisture Content in Wood
Wood is a material that expands and contracts with changes in moisture in the surroundings. This property means boards cut for flooring will swell and shrink in certain ways depending on the specific method used. Due to the direction of the growth rings, plain sawn boards change in dimension in width. The wider the board is to begin with, the greater the potential for change. Rift sawn and quarter sawn boards will expand and contract in thickness due to changes in moisture.
How Hardwood is Dried
Drying the lumber used for a hardwood floor is one of the most important aspects to how the finished product looks in a home. On the surface, this appears to be a very mundane task. It’s impossible to tell from looking at a board whether it was dried using the proper methods or not. However, if you want to have a stable and high-quality wood floor, it’s imperative to start with materials that were dried properly.
Before you can understand the procedures involved in drying wood, it’s important for you to understand the way a tree grows. Their medullary rays act in the same way as the veins in your body — they transport nutrients through the trunk to the parts of the tree where they are needed while the tree is in the ground.