Page 12 - ProInstallerJanuary-February 2022
P. 12


        Identifying Wood Distortions &


        By Brett Miller, NWFA Vice President Technical Standards, Training & Certification

                ood floors are a product of nature. They are   •  Maintenance-related issues, including:
                produced from living organisms—trees—and like   •  Wet-mopping resulting in standing/topical liquid
        Wall living organisms, respond to the environment      moisture left on the floor.
        in which they are placed. In fact, wood floors literally
        change every day. Most of these changes are subtle and   •  Use of steam mops/cleaning devices.
        undetectable, but there are times when the changes can   •  Use of non-breathable rugs on the floor.
        be very noticeable—or even destructive. Three of the most
        commonly noticeable and/or destructive changes that can   •  Not maintaining relative humidity levels year-round.
        be experienced by wood floors include cupping, crowning   •  Wood flooring installed at a lower moisture content
        and dry cupping.                                       than the in-use conditions allow.
                                                             •  Wood flooring installed in an environment drier than
                                                               the in-use conditions.
                                                             •  Over-wetting the wood when water mopping, applying
                                                               wood bleach, or reactive conditioners. Over-wetting
                                                               would be described as liquids running down the cracks
                                                               between the boards.
                                                             •  Slight cupping/edge-lift can occur with normal
                                                               application of water-based sealers and finishes,
                                                               water-based stains and water-soluble dyes, or with
                                                               application of multiple coats of water-based finish
        Cupping                                                in one day, prior to previously applied coats being
        Identification                                         adequately dried.
        Cupping is a concave or dished appearance of individual   •  Slight cupping/edge-lift can occur when floors have
        boards with the edges of the board raised higher than the   been damp-mopped in dry-climate conditions.
        center.                                              •  Solid flooring may cup when a wood floor experiences
                                                               conditions that cause rapid drying on the surface.
        Causes                                               •  Cupping can occur with use of water-based adhesive
        Cupping typically is caused by dramatic fluctuations   under floors not recommended with these types of
        in temperature and/or humidity, which can include the   adhesives.
        following:                                           •  Cupping also can occur prior to installation, as follows:
          •  A moisture imbalance through the thickness of the
            board; the wood usually has a higher moisture content   •  Improper or unmanaged handling of the environmental
            on the underside than on the top.                  conditions surrounding the flooring material after it
          •  An increase in moisture conditions, including:    was manufactured, either during transport, while in
                                                               storage or while acclimating at the jobsite.
          •  Inadequate or inoperable HVAC systems, resulting in   •  Engineered flooring manufactured out of balance (core
            elevated humidity levels.                          and wear layer having an unbalanced EMC).
          •  Wet subflooring (wood or concrete slab).
          •  Inadequate moisture control systems installed beneath   Cures
            the wood floor.                                 Never attempt to repair a cupped floor until all of the
          •  Poor building drainage resulting in rainwater runoff or   sources of moisture have been located and eliminated.  Photos courtesy of National Wood Flooring Association
            subsurface groundwater.                         The moisture content of the solid wood floor must be
          •  Moisture from inadequately ventilated or       at equilibrium with the expected in-use (normal living)
            unconditioned crawl spaces or basements.        conditions prior to resanding a cupped floor. As long as
          •  Portable water sources/appliances, building leaks or   the wood is not permanently deformed or damaged, the
            plumbing leaks.                                 flooring should return to its original shape and size when
                                                            it returns to its original moisture content. This process
   7   8   9   10   11   12   13   14   15   16   17