Hardwood Floors October/November 2017

AT THE SITE

By Brett Miller

‘TIS THE SEASON: Understanding Seasonal Related Issues

across its outer face, which can exert enough force on the core material to pull the edges of the plank upward. is causes a cupped appearance across the width of the board. e e ects of these seasonal uctuations can be compounded in some new construction scenarios. Energy-conscious homebuyers and homebuilders have, in recent years, demanded tighter, more energy-e cient homes, which can inadvertently become detrimental to wood building components and their ability to perform, if not properly addressed. is construction practice, by design, prevents warm or cool air loss, but also seals in the new home’s moisture. Moisture from the entire building process is not allowed to dissipate quickly enough. is moisture comes frommany sources including hundreds of gallons of water used in the placement of concrete, masonry, thin-set, tile mortar, drywall, plaster and many other building components. is will o en cause wood ooring and wood sub ooring to take on this moisture. When the home dries out and nally nds equilibrium in the home (o en 6-12 months a er the home has been moved into), the ooring and/ or sub ooring materials shrink, and again result in what could then be considered abnormal gaps. If the environment remains at these conditions, the gaps will likely never completely close back up in the humid months.

All solid ooring, including properly speci ed, manufactured, and installed wood ooring should be expected to have seasonal gaps between boards during the dry months when no supplemental humidi cation is added. e width of the boards, the species, and how it’s cut from the log can all a ect how much solid wood ooring is a ected by this change in moisture. In general, how much solid wood ooring shrinks is directly proportional to its width. For example, in identical scenarios, an 8” wide plainsawn plank of white oak ooring will shrink twice as much as a 4” plank of the same cut and species. Seasonal gaps between boards are more prominent with solid wood ooring products than with engineered wood ooring products. e structural composition of engineered wood ooring inherently allows it to be more dimensionally stable than solid wood ooring. Although engineered wood ooring is more dimensionally stable than its solid counterpart, it will still react to these low humidity levels but will show itself di erently. When the relative humidity levels remain below the manufacturer’s recommendations for long enough, engineered ooring will begin to dry cup. When this happens, the wear layer loses moisture (same as its solid counterpart) and begins to shrink

Fall is here, which means that across the U.S., the temperatures are cooling and interior humidity levels are dropping. Soon, heating systems will be kicking on, and phone calls from concerned homeowners will begin rolling in. Seasonal related issues are one of the most common complaints that homeowners have this time of year. As ooring professionals, it’s our role to understand and properly address the issues, while simultaneously educating the customer and providing themwith the information necessary to maintain and live with wood oors. Nearly every wood oor will have some seasonal separation between the individual boards – gaps – throughout the oor during the fall and winter months. When the air in the building is heated, the relative humidity levels drop. When this happens, the wood loses moisture as it equilibrates to the drier conditions and boards begin to shrink. As a result, gaps begin to appear between boards. is is a normal phenomenon and is directly related to the reduction of moisture in the surrounding air.

Once seasons change and the interior heating systems are

turned o , or when supplemental humidi cation is introduced and the indoor environment regains moisture, most of these seasonal gaps will disappear.

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