Hardwood Flooring

Hardwood flooring and engineered hardwood flooring is made from hardwoods that are harvested from broadleaf trees as opposed to softwood trees harvested from trees with needle-like leaves (i.e., evergreens trees). The term hardwood does not necessarily relate to the impact resistance of the wood. Most hardwoods are applied directly to the floorboards; however, engineered hardwoods are often installed overtop of a plywood substrate. Plywood substrates add stability and increase resistance to shrinkage.

Both hardwood and engineered hardwood floors use real wood for the cosmetic surface of the floor. Generally speaking, solid strips of hardwood flooring are installed in a linear or parquet pattern. Each piece of wood in a hardwood floor is unique – grain structure, knots, dark and light patches add character, warmth and charm to the hardwood flooring. Even in choice and select grades of hardwoods, these variations will exist.

It is important to remember that each piece of wood in a hardwood floor is unique. Grain structure, knots, dark patches and light patches are points of character that add to the warmth and charm of hardwood flooring. Even in Choice and Select grades of hardwood these variations will exist.

Did you Know?

New materials such as bamboo flooring, manufactured from the bamboo plant, are also included in the hardwood-flooring category because of its physical similarities to hardwoods. Bamboo is becoming a popular “eco-option” because it is a highly renewable source of material. Bamboo, which is actually a grass and not a wood, can reach full maturity in 3-5 years.

Hardwood Flooring and Moisture

Hardwood flooring is highly susceptible to changes in indoor humidity. The first two years are especially critical for wood flooring, while the wood normalizes to climate conditions. Hardwood floor manufacturers suggest relative humidity settings of 40-50 percent year-round to minimize cupping and crowning; however, this is unrealistic in colder winter climates without experiencing condensation on exterior components of the home (i.e., windows). The amount of humidity maintained in your home must be balanced to provide your family with comfort, minimize condensation as well as maintain your hardwood floor. Excess humidity must be controlled through reduction and ventilation, while excessively dry conditions must be addressed by adding humidity to the home.

Cracks Between Strips of Hardwood

Cracks can develop between strips of hardwood if the wood loses moisture due to very low relative humidity in the home. To address this issue, adjust the humidity level in your home accordingly, especially during the winter months.

Depending on your hardwood flooring type, climate and interior home climate, the following flooring characteristics are worth noting:

  • Areas around heat registers and areas exposed to direct sunlight may be more susceptible to shrinkage because of changing temperatures.
  • Broader strips of hardwood are more prone to cupping and cracking than narrower hardwood strips.
  • Quartered vertical grain wood flooring is more stable than plain or flat-sawed materials.
  • Darker coloured hardwood floors with low gloss finishes and complex grain patterns tend to be visually forgiving.

Useful Tip:

If floorboard cupping has not changed noticeably within a 12-month period, you may need to sand the floor flat and refinish it. After the floor has been refinished, it should remain flat as long as the environment does not change from the previous norm. For the permanently cupped floor that shows small differences in cupping with the seasons (i.e. cups more during the humid season) sanding at mid-season (spring, fall) can mediate the expected change. Contact a professional service provider for assistance.

Cupping and Crowing of Hardwood Boards

When wood absorbs moisture from the air or gives up moisture to the air, the wood fibres will expand, stretch or shrink. This will happen faster at the edges of the boards than in the middle of the boards and can cause cupping, crowning and separation to occur.

Cupping usually occurs when the unfinished side of the flooring is exposed to excess moisture. This can cause the edges of the wood boards to swell and rise higher than the center of the boards. The moisture may come from a water leak or originate from a previously wet area such as the sub- floor, crawl space, or a freshly poured basement floor slab. If excess moisture is causing cupping, identify the source, remedy the problem, and then allow the flooring to reacclimatize to the new drier environment (this may take an entire heating season). After the floor dries to normal conditions, the flooring should flatten.

Cupping can also be caused when the flooring acclimatizes to an area that has higher moisture content than the moisture content of the wood at installation. This type of cupping is generally permanent and changes little with the seasons.

Crowning occurs when the wood flooring loses some of its moisture, shrinks on the underside and flattens leaving the edges of the strips lower than the center of the board. Most often this happens after a floor is sanded where cupping has occurred. The upturned outer edges are sanded off and become slightly thinner than the middle of the boards. If these boards later dry and flatten to their original position, the thin edges recede, leaving the top of boards lower than the centers.

In some cases, a slight cupping or crown can be a seasonal occurrence and the issue will diminish over time. If the cupping or crowning is constant in a particular piece of wood, it can usually be replaced to fix the problem.

Hardwood Flooring and Radiant Heat

Wood flooring applied over a floor with radiant heating underneath will be more susceptible to cracks between the strips of wood. Radiant heating systems should only be used if they are engineered for wood flooring and are set to the correct heat source temperatures and thermostat controls. Engineered wood flooring with attached wooden sleepers may be a better choice for use over radiant heated floors than directly applied hardwood flooring.

Did you Know?

A one hundred pound lady wearing high heels can exert over 400 pounds per square inch at the heel of her shoe. In some case, this is enough pressure to dent hardwood floors. High-heeled shoes should not be worn on hardwood floors.

Pops and Other Sounds

Parquet or laminated woodblock flooring may make noises resembling “cracks” or “pops” as it expands and contracts. These noises do not happen often and should not be cause for alarm. Often times, exotic woods with extreme hardness and stability will pop and crack as they adjust to their new environment.

Durability Considerations

Most hardwood flooring products are pre-finished with aluminum oxide and UV- cured urethane to protect against weathering. These coatings are extremely hard and long lasting, however, the wood beneath the coatings can still be dented.

To a degree, the durability of your wood floors depends on how well they have been protected from the abrasive effects of dirt (especially sand). A protective runner in hallways, in front of kitchen sinks, and in areas where foot traffic is heaviest can minimize wear patterns. When renovating, consider installing an alternate material at entry points to reduce the opportunity for abrasives to come in contact with hardwood flooring.

General Maintenance

Hardwood floors can be vacuumed using a soft head attachment specifically designed for hardwood flooring. A power head (beater bar) should not be used on hardwood floors. A damp cloth or mop can be used to clean floors followed by a dry cloth – never leave standing water on the surface of a hardwood floor.

Corrosive solutions, chlorine cleaners or abrasives will dull the finish of a hardwood floor. Use only cleaners recommended by the manufacturer of the hardwood flooring. Commonly available cleaners, soaps, oils, waxes or polishes can damage the finishing on the flooring. Many “off-the-shelf” cleansers can damage hardwood flooring; there is no hardwood floor-cleaning product that has been universally recommended by hardwood manufacturers.

Direct sunlight can fade hardwood flooring. Close curtains or apply window films to filter the light and reduce the fading effects of sunlight on hardwood floors.

For more information on hardwood flooring, visit the National Wood Flooring Associationʼs website at www.woodfloors.org.