hardwood floor cupping

Moisture Control and Hardwood Floor Cupping

When winter comes, can spring be far behind? I don’t think Shelley was thinking about crawl spaces when he wrote this line, but spring and summer are coming and that has the folks at Carolina Energy Conservation thinking about our busiest time of year.

We’ll be getting lots of calls from folks concerned about their crawlspaces. For one reason or another, homeowners have found it necessary to get into their crawlspaces and have discovered all sorts of unpleasant things. I even had one gentleman call and say that his crawlspace was like a rain forest with water dripping off the floor joists, duct work, plumbing, and insulation. There are all the nasty, musty smells. Some have called because their neighbors have told them how much cleaner their homes seemed after encapsulating.

One of the most frequent calls we get is about beautiful, expensive hardwood flooring that is cupping or, even worse, buckling. Cupping occurs when the sides of a flooring board are higher than the center of the boards-the surface of the board has a concave shape. Solid and engineered wood flooring can both cup.

Cupping is the result of a change in moisture content from one side of the flooring board to the other. Specifically, in the case of cupping, the crawl space (bottom) side of the floor board is exposed to a higher relative humidity than the living space (top) side of the floor board.

In 99.9% of the cases the problems of cupping and buckling of hardwood flooring are caused by excessive humidity. With the hot, humid weather that South Carolina and particularly Myrtle Beach and the Grand Strand experiences every summer, the problems are compounded. Being always shaded and usually below grade, a crawlspace is naturally cooler than the outside air. When the hot, humid outside air enters the crawlspace through vents or other air leaks, the water in the humid air condenses on the cooler surfaces just like water condenses on an iced tea glass sitting on your kitchen table. In extreme but not uncommon cases, so much water condenses that it begins dripping off the crawlspace surfaces and it begins to “rain” in the crawlspace. This creates the problem. Hardwood floors cup because of the differential in moisture content between the bottom, unfinished surface of a floor-board and the top, finished surface of the floorboard in a conditioned living space.

The Internet is full of information from hardwood flooring manufacturers and installers about hardwood floors that are cupping and buckling. Their customers spend a small fortune installing flooring then think that the flooring was defective or the installation was improperly done because their flooring cupped, sometimes just weeks after installation. In fact, the cupping was caused was moisture problems inherent to the house itself.

What do the manufacturers and installers recommend? In every case, they say the problem needs to be addressed at the source – the moisture differentiation between the crawl space and the living space. According to the usfmhi, a factory direct manufacturer of wood flooring, “Deal with the building environment. These solutions (reducing ventilation, controlling water in crawl spaces or basements, adding dehumidifiers or modifying AC systems) aren’t up to flooring professionals. Building owners can take steps to reduce ventilation rates, reduce moisture intrusion and/or add mechanical dehumidification”

And when it comes to venting, the USFMHI goes on to say, “Venting very often makes a cool crawl space not just humid, but wet.” And according to Sullivan Hardwood Flooring, another manufacturer of wood flooring, “The more ventilation, the more moisture is getting into the house, and the more moisture we need to remove. So, reducing ventilation can be beneficial.” If venting to the outside is part of the problem, what is the solution? “Temperature doesn’t matter in a crawl space, so an unvented crawl space with a dehumidifier is a great, efficient way of controlling humidity levels below wood floors that are over a crawl space.” According to Sullivan.

At Carolina Energy Conservation, we’ve been making South Carolina homes along the Grand Strand more energy efficient for a decade. We believe the most cost effective solution to hardwood floor problems is crawlspace encapsulation. We use the recommendations of Advanced Energy, the EPA, and the Department of Energy as the guidelines for our encapsulations. Our goal is to make the process as easy and cost effective for the homeowner as we possibly can.

Crawl space encapsulation involves first mitigating any standing or running water with rough grading, perimeter drains, and a sump pumps if necessary. Then the crawl space is sealed by closing the exterior vents, sealing the walls and piers, and installing a high quality 20-mil vapor barrier to the floor. All vapor barrier seams are sealed. Finally, Carolina Energy Conservation conditions the crawl space air by insulating the space and adding a dehumidifier.

The key is bringing the crawl space relative humidity to 60% or less. At less than 60% moisture will not condense on cool crawlspace surfaces, mold and mildew will not grow, and the likelihood of hardwood floors in the living space cupping or buckling is minimized.

If you are experiencing problems with your hardwood floors buckling or cupping, or have grown tired of that damp, musty smell emanating from your crawlspace, Carolina Energy Conservation would be happy to give you a free, no obligation assessment of your crawlspace. We have solutions to home and crawl space moisture problems. Call us at (843) 342-9555 or visit our crawl space web site at www.ceccrawlspacerepair.com