The Appeal of Wood Flooring?
A wood floor is a great investment and its ability to last a lifetime also makes it one of the most cost effective flooring options available.
While longevity is an appealing feature of this flooring, the most appealing characteristics of wood, are its warmth, character, and rich, natural beauty. The natural grain and characteristics of wood provide it with an unmatched "personality" that will enhance any space. The variety of colors, species and finishes of wood flooring make it easy to compliment any room décor with style and beauty.
Unlike most floor coverings, wood floors are derived from a natural resource –trees. There are over 50 species of trees whose wood is used for flooring including both domestic and imported varieties. The wood species selected will influence the natural color, durability, and cost of the floor. The most popular species used by the flooring industry will be presented in detail within a separate module of this course.
The domestic hardwood used for flooring is harvested from well-managed forests. The days of clear cutting timber with no thought for the long-term consequences are gone. Today, nearly twice as much hardwood grows each year as is harvested in the U.S. The forest management practices put into place have made domestic wood one of the most eco-friendly flooring options available.
Most of the imported or exotic species used by the flooring industry are taken from well-managed forests, though because of past political and environmental issues within many of these countries of origin some customers may view the use of these species as controversial.
Features, Advantages & Benefits of Wood flooring
|Longevity||Can be refinished and re-stained||Saves money & time by refinishing, not replacing.|
|Durability||Will stand up to the demands of an active household.||Floors stay looking new and beautiful longer.|
|Sustainability||American hardwoods are a renewable resource from carefully managed forest.||Environmentally friendly|
|Selection & Variety||Available in numerous sizes, styles, colors, finishes and species||Floors can compliment any décor.|
|Non-allergenic||Won't trap or retain dust||Healthier indoor environment|
|Urethane Finish||Easy to maintain||Saves time, less cleaning|
|Cost Eeffective||Adds value to a home||Higher resale value when home is sold.|
Types of Wood Flooring
Solid Wood flooring is just as the name implies—solid wood throughout. Solid wood flooring is sensitive to moisture and cannot be installed directly over concrete or below grade (below ground level). These floors have tongue and groove sides and are available in pre-finished or unfinished styles.
A major benefit of solid wood flooring is that it can be refinished several times, adding to its versatility and longevity.
Engineered wood floors are composed of thin layers of wood that are bonded together to form a single board. The layers are not necessarily all the same species. The final layer of veneer that is glued onto the supporting layers determines the species of engineered wood flooring.
Often produced with three to five layers, these boards are not as susceptible to moisture damage or expansion and contraction as solid wood floors. Engineered wood floors can be installed on any grade level of the home: below grade, on grade or above grade, including basements and humid climates.
Acrylic impregnated wood flooring is another type of wood flooring that is used primarily in commercial settings or high traffic residential areas, such as kitchens and family rooms.
These pre-finished wood floors are injected with acrylic and color to create a highly resistant and durable surface. The acrylic fills the pores of the wood making it more moisture and wear resistant than solid or engineered wood floors.
These floors are available in the same sizes and shapes as most engineered wood products.
Wood Floor Finishes
Both solid and engineered wood floors are available as unfinished or pre-finished. The costs for pre-finished and unfinished floors are about equal. Pre-finished flooring costs more to buy, but less to install. Unfinished floors cost less to buy, but the sanding and finishing increases the labor costs, making installation more expensive.
Unfinished flooring must be sanded and finished on the job site after installation. The process can take several days and is dusty and disruptive. The advantage of unfinished flooring is that an installer can better match the stain color of existing floors or create custom designs and finishes.
Pre-finished wood floors are sanded and finished during manufacturing and need only to be installed. The convenience of pre-finished floors has made them a more popular option in recent years. These factory finished wood floors are produced in a dust-free environment, eliminating air bubbles or dust specks that can become embedded in the finish during on-site finishing.
Types of Solid Wood Floors
Solid wood flooring is available in three main forms—strip, plank, and parquet.
|Wood Type||Width Ranges||Thick Ranges||Design Effects|
|Strip||Less than 3 inches||5/16" to 3/4"||Strip hardwood floor often gives the illusion of a larger and more open space.|
|Plank||3 to 8 inches||5/16" to 3/4"||The effect produced by plank flooring is more of an antique, county, rustic look.|
|Parquet||Parquet flooring is made up of small strips of wood (1 – 6 inches long), glued together side by side to form squares. The squares (common sizes: 8" x 8", 9" x 9" and 12" x 12") are installed in alternating patterns.||Darker parquet floors generally give a room a more traditional look, while lighter woods give the room a more contemporary feel.|
Wood Floor Edges
There are also various edge choices that will affect the installed look of a wood floor. The most common edges are square, micro-beveled and beveled.
Each plank or strip fits flush to each other creating a smooth, flat surface with a contemporary look.
In between each board is a slight cut angle to create subtle depth and dimension to the floor and emphasis to each board.
With a deep groove between each board, the depth and dimension is enhanced resulting in a traditional, handcrafted, natural look.
Wood is of the most versatile flooring choices available. Wood floors can be finished with a clear coat of urethane, stained to mimic the color of another species, or painted in any color desired.
Solid wood floors and some engineered floors can even be sanded, refinished and stain an entirely new color, giving new life to an old floor. Wood's natural, unique looks and the ability to customize designs with inlays and borders make any style or color possible.
Each species of wood has its own unique grain pattern, coloring, feel and even scent. While oak remains the most popular type of wood for flooring, many people are also exploring exotic species that can add interesting textures and colors.
Botanically speaking, trees are categorized as hardwoods or softwoods. The hardwood category includes deciduous trees or trees that typically loose their leaves in late fall and reproduce with flowers and fruit or nuts. Common hardwoods are birch, elm, maple, mahogany and oak.
Softwoods are coniferous; they retain their needle-shaped leaves in the winter and reproduce by spreading their seeds through cones. Common softwoods include cedar, Douglas-fir, hemlock, spruce and pine.
Despite the names, the difference between hardwoods and softwoods has nothing to do with the actual hardness of the wood these trees produce. In fact, some hardwoods such as Poplar and Basswood are considerably softer than some conifers.
Differences in Softwood and Hardwood
Softwoods tend to grow faster than hardwoods. Softwood trees can be replanted and reharvested sometimes in as little as 15 years, whereas hardwood trees require a minimum of 75 years for most common species.
Softwoods have tall, straight trunks and tend to grow close together. Whereas, hardwood trees require more space to grow because their branches grown wide to allow the leaves exposure to the sunlight. The weight and internal stress of hardwoods' wide-spreading branches create unique and interesting figures and grain patterns within the wood.
Softwood trees produce wider bands of larger, less dense wood. Whereas, hardwoods have denser, more tightly grained wood. This is why it is easier to drive a nail into a pine board, than into a dense, tight-grained oak board.
Hardwoods are often used in flooring and furniture, whereas softwoods, because they are more widely available and less expensive are used for structural components within construction.
Certain hardwood species are not recommended for flooring because they're not hard enough to withstand heavy wear.
The majority of American floors during the first half of the 19th century were made from softwood boards, often laid in random widths, and never stained and varnished.
Common Hardwood Used in Flooring
Oaks, both red and white, are the most abundant hardwood species. Together, they account for 52 percent of all hardwood harvested in the U.S.
|Characteristic||Red Oak||White Oak|
|Color||Tan to reddish pink in color||Ranges from nearly white to tan/brown with yellow to cream tints.|
|Grain||Stiff, dense wood with a wide grain pattern and large pores.
Certain cutting techniques can reveal narrow medullary rays.
|Straight, wide grain pattern with longer rays than red oak. Tends to have more figures than red oak.|
|Hardness||1290 on the Janka scale
used as a benchmark for most other species.
|1360 Jankas Scale, 5% harder than red oak|
|Strength||Strong and durable, the most popular wood flooring||Stronger and resists wear better than red oak.|
|Affordability||Moderate||Moderate to Expensive|
The American maple is divided into two groups: Hard maple, which includes sugar and black maple; and soft maple, which includes red and silver maple. Second in popularity to oak, hard maple has excellent resistance to abrasion and indentation, making it ideal for flooring.
Hard maple is a heavy, strong wood with uniform texture. Its straight, fine grain with occasional bird's eye or fiddleback figure contains colors that range from blonde to light reddish-brown.
Maple is moderately priced, however can be expensive depending on the quality of the figure and grain. This wood also takes clear finishes and polishes well.
Rich, reddish-brown. Cherry darkens a great deal with age and exposure to sunlight.
Straight, fine grain and smooth satiny texture. Small gum pockets produce distinctive markings and interesting character.
Light, strong, and stiff. Only 75% as hard as red oak (950 on the Janka scale).
Birch can range in color from light yellow to dark brownish/red with light white tones.
The fine, uniform texture features medium figuring and a closed grain. Occasional curly grain or wavy figure is prominent in some boards.
About 2% softer than red oak, birch, at 1260 on the Janka scale, is still a strong wood that has good shock resistance.
Common Domestic Hardwood
There are several species of American ash: black, brown, and white. White ash is the most widely used in flooring. Click on the icons below to learn more about white ash wood.
Inexpensive to moderately priced.
Ranges from pure lustrous white to light brown. White Ash undergoes a medium degree of color change over time by ambering from a pale cream colored when freshly sanded to a more a straw tan color as it ages.
Straight, wide, pronounced grain pattern with coarse texture, very similar to red oak.
Harder than red oak, white ash is dense and has excellent shock resistance. This wood also has exceptional bending qualities.
Softwood Used in Flooring
Softwoods are typically not as scuff and dent resistant as hardwoods, but are still quite durable. There is an 800-year-old church in the Czech Republic with its original pine flooring that is a testament to the potential longevity of well-maintained softwood flooring.
Cypress or Southern Cypress
The wood from this tree is very dense with a straight even grain pattern. Not as strong as other woods used in flooring, cypress, rates only a 510 on the Janka scale. However, the natural oils in cypress' heartwood make it one of the most durable and resistant woods when exposed to moisture, insects and UV sunlight. Commonly harvested and used in Florida, Louisiana, and throughout the Mississippi Delta region of the U.S., the wood is inexpensive to moderately priced where regionally available.
Also considered an exotic or imported species but technically a softwood. Australian Cypress, is a member of the pine family and is the hardest and most durable commercial softwood in the world.
This moderate-to-expensive wood has a closed grain with colors ranging from cream to honey golden brown. Often containing numerous darker knots that give it a similar appearance to pine. Australian cypress has all the rustic warmth and character of domestic softwoods but offers more strength and durability than even oak, with a Janka rating of 1375.
Southern Yellow Pine
Southern yellow pine is warm and pale yellow in color with brown knots. This species contains high figures and patterns that range from clear to knotty. It also has a natural resistance to insects.
An inexpensive flooring option, southern yellow pine is 47% softer than Northern red oak, rating a 690 on the Janka Scale. Despite its softness, it is a fairly durable floor, but not as resistant to scuff, & dents as hardwoods.
Exotic Wood Species Used in Flooring
Exotic woods are one of the latest design trends in flooring. The color, grain and superior durability of these floors will give any room a formal, elegant and unique look.
While most exotics are more expensive than common woods such as oak, maple and ash, these unique woods can add character to a room at less expense by using them for intricate inlaid patterns, borders or medallions.
Some customers may not agree with the use of exotic woods. They feel that despite advances in forest management and land stewardship in Africa and Central and South America, using exotics is still too environmentally damaging.
Customers can still get the "look" of an exotic by using a darker finish on a domestic wood.
Popular Exotic Woods
Brazilian Cherry (Jatoba)
Origin: Brazil, Bolivia, Peru, Venezuela, Nicaragua, Mexico, Guatemala, & the Caribbean
The medium texture and predominantly interlocked grain of Brazilian Cherry is enhanced by the yellowish-pink to reddish-brown color that is often marked with dark streaks. Like most exotic woods, the color will darken rapidly when exposed to sunlight.
With moderate to expensive pricing, superior hardness (a 2350 on the Janka scale), and rich colors, it is easy to see why Brazilian Cherry is the most popular imported species in the U.S.
Eucalyptus is another popular imported species that actually represents more than 300 different sub-species. Eucalyptus trees have been successfully planted on nearly every continent from its native Australia.
Eucalyptus includes popular sub-species such as:
- the black-streaked Jarrah;
- the Spotted Gum, accented with prominent gum veins;
- the Alpine Ash with its light colored, straight grains;
- and the Lyptus, a newly marketed wood featuring grain similar to mahogany with the color of cherry.
The different species have a colors ranging from pinkish-tan to deep red with black streaks. The color tends to darken with age and exposure to light. Eucalyptus is a strong, heavy, hard wood with relatively short harvest rotations.
Additional Exotic Woods
Click on the wood samples below to learn more about each of these species.
Origin: Central and West Africa,
Characteristics: Coarse texture, straight interlocked grain. African Padauk is a medium hard species used primarily for its vibrant orange/red color. Color changes dramatically over time.
Price: Moderate to expensive
Origin: Central and South America
Characteristics: Straight, interlocking fine, even grain. Moderate color variations.
Origin: Burma, Thailand, Caribbean, and throughout the tropical world.
Characteristics: Dense, hard straight grain with an oily texture. Color ranges from pale yellows to orange browns with darker striping. One of the world's most durable and stable woods for outdoor use, teak is also a popular flooring material.
Origin: Equatorial regions of Africa
Characteristics: A uniform dark chocolate brown color, wenge also features a course texture and straight, uniform grain. Wenge also undergoes a large degree of color change with pronounced darkening within a few months from being cut.
Moisture heavily influences how wood behaves, both during the machining process and after installation. Changes in humidity levels cause wood to swell as it absorbs water, and shrink as it releases water, changing its dimensions.
The dimensional stability of wood is an important property for flooring because changes in the indoor humidity can affect the appearance of the floor. In the winter heating seasons, indoor air can become extremely dry, causing wood floors to contract, even to the point of leaving visible gaps between the floorboards. In summer months, added humidity can cause wood floors to expand and possibly warp or cup.
The cross-grained construction of engineered wood floors adds stability, making these floors more dimensionally stable than solid wood flooring. More information on this topic will be presented in the Moisture Content and Wood module of this course.
Each wood species has a level of hardness that makes it suitable or unsuitable for certain uses. Because red oak is a common wood that most people are familiar with and is of medium hardness, it is often used as the benchmark when comparing the suitability of wood for use in flooring.
To assist consumers with these comparisons, the National Wood Flooring Association has created a test for measuring the hardness of different wood, called the Janka Hardness Test. This test is a good indicator of a species' strength and durability and ultimately a floor's ability to withstand denting and wear.
The Janka (or side) hardness test measures the wood's ability to resist compression perpendicular to the grain. Measuring the force required to embed a .444 inch steel ball half its diameter into the wood is how the test is performed. The hardness is based on the average of two tests, one on a plainsawn board and one on a quartersawn board.
Strength refers to the ability of wood to resist certain stresses and strains when in use. There are a number of ways to measure the strength of wood. Two of the most frequent measurements are density and shock resistance.
In wood, density is expressed as pounds per cubic foot at a pre-determined moisture content level. Density is an important indicator of strength in wood because typically, the heavier the wood, stronger it will be. High-density woods, such as oak, also tend to be less dimensionally stable (shrink and swell more) than low-density woods, such as southern yellow pine.
Shock resistance measures the impact strength or toughness of wood. One of the primary tests used to determine shock resistance is the "impact bending" test and involves dropping a 50-pound weight on a board that is supported on both ends.
The weight is dropped onto the board at different height intervals until the board breaks. The height, at which the board breaks, is a comparative value that represents the ability of wood to absorb shocks caused by external stresses.
The average measurement for this test is in the 30 – 50 inch range.
Strength Properties of Wood
Each wood has properties unique to the species.
|Species||Strength||Shock (inches @ 12% moisture content)||Notable Properties|
|Brazilian Cherry||high||n/a||Extremely hard, dense and very strong wood|
|Hickory/Pecan||high||77||One of the most resilience floors available due to extreme shock resistance|
|Hard Maple||high||39||Dense and very resistant to abrasive wear, making it perfect for high traffic areas.|
|White Oak||high||37||Resists wear well.|
|Red Oak (Northern)||high||43||Resists wear well. Less durable than white oak.|
|Yellow Birch||high||55||A very heavy, strong, durable wood|
|Black Walnut||medium||34||Heavy, hard, excellent dimensional stability|
|Southern Yellow Pine||low||20-34
(depending on sub-species)
|Soft and easily dented.|
(depending on region)
|Soft and easily dented.|
Moisture's Effect on Wood Floors
Air temperature and relative humidity changes quickly, however, the moisture content of wood changes slowly, especially once the wood has been sealed or finished. Because of the lapse of time between changes in the air and changes in wood moisture content, short-lived fluctuations in humidity levels usually have no effect on wood moisture content.
Sustained increases or decreases in temperature and humidity, however, can influence wood's moisture content. In the winter heating seasons, indoor air can become extremely dry, causing wood floors to contract, even to the point of leaving visible gaps between the floorboards. In summer months, added humidity can cause wood floors to expand
Engineered Wood vs. Laminate Flooring
|Pattern repetitions can look artificial||No||Yes|
|Dents more easily||Yes||No|
|Easier to Install||No||Yes|
|Can be refinished||Yes||No|
|Unique character and natural appearance||Yes||No|
|High density fiber board core construction||No||Yes|
|Constructed of layers of wood||Yes||No|
|Durable, long-lasting floor||Yes||Yes|