Hardwood 101


What is hardwood flooring?

​Hardwood flooring is any flooring made from the timber of a tree. Not only are there seemingly endless options of wood species that can be used, there are also different ways of processing the timber into flooring.

What types of wood are used in hardwood flooring?

hardwood flooring planks

The woods used often fall into two main categories, domestics (domestic wood) and exotics (exotic wood). Both domestic and exotic woods are rated for hardness using the Janka Scale.

The Janka Hardness Test measures the amount of force needed to embed a steel sphere into a piece of wood in order to determine the hardness of the wood. A higher number on the resulting Janka Scale indicates a harder wood.

* Extra Credit: While a generally reliable gauge, the way in which a wood is processed can have an effect on its hardness and, as such, the hardness of individual wood flooring products may differ slightly from the Janka Scale.

Domestic woods are any species found in North America. These include, but are not limited to American Cherry, Ash, Birch, Hickory, Maple, Red and White Oak, Walnut and Yellow Pine.

* Extra Credit: Of the domestic woods, the most commonly used is oak. Oak, with a mid-range Janka Hardness of 1290 to 1360, is found in approximately 80% of the hardwood flooring available. The most common colors of oak are natural, butterscotch and gunstock.

​Exotic woods are from trees found all over the world, most often in tropical climates. These include, but are not limited to African Teak, Australian Cyprus, Brazilian Oak and Cherry, Santos Mahogany, Tiete Chestnut and Rosewood and Tigerwood.

* Extra Credit: Exotic woods seem to have a more striking appearance due to the vivid reds and yellows within the species.

While exotic woods often boast more intense color, many are susceptible to color change at a much faster pace than domestic woods and tend to be softer and less durable than domestic options. Additionally, the number of exotic wood flooring options available have decreased in response to The Lacey Act.

In 1900, the United States enacted The Lacey Act, a law banning the trafficking of illegal wildlife. The Act was amended in 2008 to include plants and plant products, including the timber used for flooring.

Hardwood floor panel options

Bamboo flooring is not, technically, hardwood flooring. While it is made from a plant, it is not a tree and thus, not wood. However, Bamboo flooring is an excellent option due to its durability and eco-friendly thanks to its rapid renewal rate.

Similarly, cork flooring, while made from a cork oak tree, uses only the bark and is thus not considered wood. Like bamboo, cork is sustainable due to its rapid renewal rate. While cork is an extremely soft option, it also tends to “spring back” and avoid permanent damage by heavy or sharp items.

Why should, or shouldn’t, I choose hardwood flooring?

There are great benefits to choosing hardwood flooring. Hardwood offers a classic look that is often less difficult to design around than carpet or tile. Hardwood is also incredibly resilient and, when well maintained, can last for centuries. Speaking of maintenance, hardwood is one of the easiest floorings to keep clean, whether by sweeping or vacuuming. Hardwood flooring has monetary value as well, by increasing property and home value.

On the other hand, despite its name, hardwood flooring can be vulnerable to indentations and scratches from things like furniture, high-heeled shoes and animal nails. Hardwood flooring is also extremely sensitive to moisture and humidity, making it a poor choice for certain areas (bathroom, laundry room, basement). Something else to consider is the noise level of a house with hardwood will be higher than that of carpet, which can absorb some of the volume. Like carpet, hardwood can fade over time due to exposure to direct sunlight.

One of the most important factors to take into account when considering hardwood flooring is moisture.

Hardwood flooring that is exposed to excessive moisture can swell. When individual planks swell, they cause an increase in pressure between the planks and across the entire surface of the floor. That pressure can cause boards to warp or cup.

* Extra Credit: Excessive moisture is not limited to flooding or a prolonged leak. Humidity over 55% can cause just as many problems as standing water.

Is all hardwood flooring made the same way?

There are two types of hardwood flooring. Solid hardwood and engineered hardwood.

Solid hardwood flooring is comprised of planks of solid finished or unfinished wood, each made from a single piece of timber, that are pieced together with tongue and groove sides and ends. Solid hardwood flooring can be nailed or stapled in place, but should not be glued.

* Extra Credit: Because solid hardwood is more sensitive to moisture than engineered hardwood, it should only be used above grade (above ground) or on grade (ground level) provided it is not directly on top of a concrete slab.

Engineered hardwood flooring is multiple layers of plies (very thin sheets of wood) that have been pressed together, each layer laid perpendicular to the next. This crossing of direction creates a single piece that is less sensitive to moisture and offers greater dimensional stability. The top, surface layer, is called the veneer.

how engineering hardwood flooring is constructed

​Wood used in engineered hardwood flooring is processed in one of two ways:

Rotary peeled veneers, also known simply as peeled veneers, are created by sharp knives cutting into a log using a circular motion across the surface. It can be imagined as “unrolling” the log. Using this process on certain species, like oak, can provide unique, broad grain effects.

Plane sliced veneers, also known as sliced veneers, are created cutting along the length of the log in a straight line, producing a graining that more closely matches solid wood flooring. Since this process utilizes less of the log than peeled veneers, it is often more expensive.

how veneer for hardwood flooring is cut from wood

*Extra Credit: Not only can engineered hardwood be installed in any room, including below grade (below ground), but it can sometimes be placed directly over old flooring, whereas solid hardwood cannot.

What does grade mean?

When it comes to flooring, the term grade actually has two meanings.

The first meaning, as noted above, refers to ground level. Anything above grade is above ground level. At grade is ground level and below grade is below ground, like a basement.

The second connotation of grade refers to the appearance of natural wood as it appears in flooring. When used in this way, grade takes into account color, length, knots, streaks and more.

grade for flooring installation

* Extra Credit: While lower grade flooring options may appear less expensive on the surface, lower grade flooring can often incur additional costs in labor and waste, and often carries no warranty at all.

What style options are available for hardwood floors?

Both solid and engineered hardwood flooring come in many different widths. Different widths are available between different products as well as within a single product, which can create a unique flooring pattern.

Single-width flooring (also called fixed-width) refers to a surface comprised entirely of uniform-width planks.

​Gaining in popularity is mixed or variable-width flooring, wherein the planks vary in widths across the covered area.

* Extra Credit: Thinner width options are often called strips, while wider pieces are referred to as planks. Strips can visually expand a small room, while wider pieces work best in larger areas.

Along with width options, the surface edges of flooring planks can differ in shape. The lengths of planks can have square, beveled or pillowed edges, creating different surface appearances.

Different kinds of edging on hardwood floor

Square edges are 90 degrees. The planks fit completely flush with one another to create an unbroken surface.

Beveled edges are trimmed from the side toward the surface of the plank. Two beveled edges placed alongside one another create a v-shaped space along the seam.

Pillowed edges can be considered a “rough” version of a beveled edge, where the edges are gently rounded, rather than a well-defined angle.

* Extra Credit: An eased edge is a beveled edge that is less pronounced and creates a shallower groove. This type of edge is also referred to as micro-beveled, although some manufacturers now use the terms eased and beveled interchangeably.

Do all hardwood floorings have the same texture?

All hardwood floorings do not have the same texture. Along with options in species, color and hardness, there are texture options that change the feel and appearance of hardwood flooring; smooth, hand-scraped and wire- brushed.

Smooth hardwood flooring uses no added textures, whether man or machine made. This provides a flooring with the most genuine reflection of the species from which it has been created.

When a hardwood flooring is described as hand-scraped the surface has been treated with a draw knife (single blade with handles on either end) to create smoothness. While there is an overall smoothness, the process also creates scrape marks that provide depth and individuality to the flooring. Despite the name, hand-scraping can be performed by an individual or by a machine.

Wire-brushed flooring (also referred to as etched or distressed flooring) is much like it sounds. Wire bristles pull the soft grain from the timber, “opening” the wood grain. Following the brushing, the boards are then sanded down, reducing the depth of the texture but retaining the unique appearance that the process creates.

With so much wood exposed in a plank, how is the flooring protected from damage?

After hardwood planks have been textured (if applicable), they still require finishing prior to being used as flooring. Planks are sanded, stained and sealed to protect the wood from damage. The process can be performed on individual planks prior to installation or after all planks have been fully installed in a space.

Prefinished hardwoods (sometimes simply called finished hardwood) have been sanded, stained and sealed prior to installation.

hardwood floor receiving stain

Unfinished hardwoods have been fully installed and the entire space is sanded, stained and sealed in place.

* Extra Credit: most sealants used on hardwood floors are urethane-based. The sealing process protects from not only everyday wear but also staining, discoloration and moisture penetration.

Are there limitations to where I can install hardwood flooring?

Due to its susceptibility to moisture penetration (even when sealed), solid hardwood flooring performs best when installed above grade (above ground). It can be used at grade (ground level), provided it is not installed directly on top of a concrete slab.

Engineered hardwood is more resistant to moisture than solid hardwood and, in addition to use above grade and at grade, it can also be used below grade (below ground).

How is hardwood flooring installed?

Proper installation of hardwood flooring involves many steps, including significant preparation.

Any area in which hardwood flooring may be installed should first be submitted to moisture testing by a professional using the appropriate equipment. If a significant amount of moisture is detected, the problem must be remedied prior to installation.

Once an area has been deemed suitable for hardwood flooring, the environment should be stabilized and kept at a constant temperature for up to two weeks prior to installation.

At least 48 hours prior to installation, the hardwood flooring should be placed into the area in which it will be installed. This allows the planks to acclimate and become unified to the temperature and humidity in which they will remain.

​In addition to the above steps, it is highly recommended that some sort of additional moisture protection system, like a moisture retardant, is put in place. For example, Bob’s Carpet & Flooring offers a Moisture Protection System in which a Moisture Vapor Protection surface membrane is placed over the (properly prepared) concrete subfloor.

Once preparation is complete and the flooring planks have been acclimatized, there are four primary ways in which hardwood floors are laid and affixed. It is always best to refer to the manufacturer’s guidelines, but the method of installation will depend upon both the type of flooring you’re using and the area in which it is being installed.

Installing hardwood flooring over plywood

Solid wood flooring requires either nail down or staple down installation.

Nail and staple down installations are very similar. The difference between the two is exactly what their names suggest; nail down installation uses nails, a flooring nailer and a mallet, while staple down installation is achieved with staples and a pneumatic staple gun.

Engineered hardwood flooring is installed using the glue down or floating method.

Glue down installation uses adhesive to join the hardwood and subfloor.

Floating installation is unique from the other forms in that the flooring is not permanently affixed to the subfloor. A thin pad is placed between the subfloor and flooring, allowing the flooring to expand and contract with humidity, protect against moisture, absorb sound and provide cushioning. As a general rule, only engineered hardwood floors can be floated.

After the hardwood flooring is installed I’m done, right?

Not quite yet, no. To complete, enhance and showcase your new hardwood flooring you’ll want to consider finishing trim, like moldings and transitions.

Base and quarter round moldings serve a functional purpose – filling any space/gap between flooring and a wall, as well as covering the seam where the two meet.

Transitions are moldings that function where hardwood flooring abuts a surface other than a wall.

T-moldings are used between two surfaces of equal height, often to provide room for natural floor expansion or allow the flooring panels to change direction.

Reducer strips are placed along the edge of flooring when it abuts a surface that is lower in height.

Thresholds are moldings that allow for movement and/or expansion space while creating a smooth finished transition. An example would be flooring meeting a sliding door.

Stair nose moldings are used on the edges of significantly raised surfaces, like stair steps. Bullnose stair moldings are rounded, while square nose stair moldings have 90 degree corners.

Different types of molding for floors


How can I prevent damage to my hardwood floors?

There are a number of things you can do to help ensure your hardwood floors will look beautiful for years to come. A little preventive maintenance goes a long way!

Stain offers wood protection from moisture and sunlight. Finished flooring will already have been stained prior to purchase and installation but unfinished flooring, and floors in the process of being refinished, can reap the protective benefits of stain.

Rugs and mats offer a stylish opportunity to protect your floors from dents and scratches. By placing rugs or mats in high-traffic areas, you can avoid excessive wear while showcasing your design style. Rugs and mats also help collect dirt and grime when placed inside and outside main entrances.

rug protects hardwood floor

* Extra Credit: Avoid rugs with rubber or petroleum-based backings. These backings can trap moisture and cause damage to the flooring. Instead, use underlayments that have been recommended by the manufacturer.

Furniture coasters, also called pads or glides, can be an excellent barrier to place between heavy furniture and your floor. These come in many different shapes, sizes and materials, allowing you to choose the appropriate option for your furniture and flooring.

* Extra Credit: Plastic wheels on furniture make for easy moving, but can also cause heavy scratching. 

Periodically rotating rugs and furniture (with the appropriate protection) will help prevent changes in color, over time, due to differing levels of sunlight. Window treatments can also reduce sun exposure.

Certain footwear can be hazardous to wood flooring. High-heeled shoes create a concentration of weight and pressure on a small area (the heel). That focused exertion can cause denting, particularly on softer woods.

Dog may be man’s best friend, but a dog’s nails can be trouble for hardwood floors. The best way to avoid scratches is to always keep your pets’ nails or claws properly trimmed.

As with any home furnishing, the best prevention is through maintaining a clean product. Hardwood floors should be swept daily and vacuumed weekly.

How should hardwood flooring be cleaned?

Regular maintenance of hardwood flooring includes sweeping and vacuuming. Washing and polishing may also be performed if so advised by the flooring manufacturer.

When sweeping, use a good, quality broom that won’t scratch your floors. Hardwood flooring should be swept daily, particularly in areas of high traffic.

sweeping hardwood floors with a broom

Over time, with excessive traffic, floors can require a refresh that goes beyond simple cleaning. Screening is a way of removing flooring finish without damaging the wood itself. A  fine mesh is used with an electrical buffer. After the finish has been removed, new coats of urethane can be applied to most hardwood floors.

Are there green, or eco-friendly, hardwood options?

Bamboo flooring, while not technically hardwood flooring, is a plant-based option that looks much like wood flooring. Its rapid renewal rate makes it a particularly eco-friendly option.

Cork flooring which, although made from a cork oak tree, is not considered wood. Like bamboo, cork is sustainable due to its rapid renewal rate.

Because hardwood flooring is made from a naturally occurring substance (wood), it is innately “green”. Additionally, timber used for hardwood flooring can be sustainable when it is properly (sustainably) harvested. The Forest Stewardship Council (FSC) independently certifies environmentally sustainable, socially beneficial and economically prosperous foresting practices worldwide. You can find the FSC certification on several hardwood floorings.

While pre-finished and engineered hardwood flooring go through processes that may involve the application and/or absorption of chemicals, the California Air Regulatory Bureau (CARB) places limits on volatile organic chemical (VOC) levels that may be present. For example, formaldehyde naturally occurs in wood. However, many resins used in engineered hardwood can contain additional amounts of formaldehyde. CARB Compliant hardwood flooring, has been tested and contains only minimal, non-harmful levels of formaldehyde.

eco-friendly green cork and bamboo flooring

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