Why does hardwood floor cup

Hardwood cupping can lead to more serious issues such as cracked boards and peeling finish and could eventually cause the flooring to buckle. High Relative Humidity Even the most carefully installed flooring can be subject to hardwood cupping , especially during the humid summer months.

If the cupping is throughout your home, humidity is likely the cause. If the HRV is turned on during the summer, it will continually bring the damp air from outside into your home. Subfloor Moisture Another common cause of hardwood cupping is a sub-floor that has higher moisture content than the wood itself. This can happen to hardwood floors installed in a new construction home without heat or air conditioning when the floor is installed. It is not hard to see the effect in wood flooring, either.

For many species and aspect ratios, a piece of flooring placed on a towel that is kept moist will show some cupping in a day or two. Very noticeable cupping will occur within a few days. With those demonstrations, the source of the water is easy to identify because the water is liquid, but wood can also take on water vapor from the surrounding air to cause swelling in the same way. Any air that has a relative humidity RH above zero has water vapor mixed into it.

Given enough time, the MC of wood will come to an equilibrium value based on the RH of the air. If the MC is increased, the wood will swell, just as it does when liquid water is introduced. The vapor-driven process is slower than when liquid water is present. Problems caused by water vapor can take several weeks or even months to become evident.

One instance that involved a delayed manifestation of a cupping problem was a wood floor installed on the second of three levels in an existing structure in a warm, humid climate. After the floor had performed well for a year and a half, the floor suffered a serious failure within the period of a few weeks and had to be replaced.

The failure was due to a hidden defect in the original wall construction that allowed air to enter the space between the ceiling of the first floor and the subfloor of the second level.

In this case, the moisture reached a level in the flooring that was sufficient to generate areas of buckling and splits in some boards. When the water that causes cupping comes from plumbing, appliance or building leaks, or from site grading problems, it is often straightforward to diagnose the problem. The source of problems caused by moisture vapor can be more difficult to find, especially in today's building envelopes with complex water vapor dynamics.

Changes to air, moisture or thermal barriers in an existing building can cause problems with wood floors that have performed well for years in the past. It is not unusual to have seasonal cupping in these cases. In warm climates, air intrusion below a conditioned space, moist crawl spaces or inappropriately sized air conditioners can all cause moisture problems. Water vapor emission from concrete or a wet subfloor can cause a cupping problem in any climate.

Swelling is the largest in the tangential direction, which is across the face of plainsawn flooring or across rotary-peeled faces. The amount of cupping will depend on the species swelling coefficient , cut, width, thickness and the restraining forces that may be present.

A floor that has water introduced to it from the top may cup as the water goes between the boards and enters the wood from the bottom. This is likely to be the case when a wood floor has finish on it. Floor finish slows water movement but does not stop moisture passage into or out of the flooring completely, so wet floors that have finish on them dry out slowly. As wood responds to environmental changes, the boards in a floor can experience forces from adjacent boards and from the subfloor.

Hence, this process is better left in the hands of flooring experts because any minor glitches can lead to other problems, such as crowning, costing you even more. If you have not yet, call in professional hardwood floor experts to restore or replace the exact size and length of the cupped portion of the floor.

If the damage is extensive and has spread to other parts of the floor, you will need to get your entire floor replaced. At Wall2Wall, we are known for providing fast and effective repair services, regardless of the extent of the damage. Considering that no other remedy has helped reverse your cupping, it shows how serious an issue it is and calls for urgent fixing.

While hardwood floor cupping can be reversed, it is a nuisance to manage. So, why not take precautions beforehand to prevent this phenomenon from taking place. One of the best prevention tactics is to control the moisture content and humidity levels in your home.

You should also make sure the wood planks are properly installed and the moisture content is at the optimum level during the installation process. Hardwood floors need to be cleaned maintained, but make sure you use as little water as possible while mopping.

And can it be stopped? Cupping is one of the unfortunately common issues that can plague hardwood floors. But if you catch it early and can address the moisture issue, there is hope in getting your floor back to normal. When moisture interacts with a hardwood floor, the side of the boards closest to the moisture expands. This expansion can be in the form of cupping the center of the board is lower than the edges or crowning the center of the board is higher than the edges.

Both situations, although different, are both due to a moisture imbalance in the boards caused by either the addition of moisture or the extraction of moisture from the floor. Sometimes the early stages of cupping can be noticed when light comes in from a window and reflects onto a wood floor. You can see small shadows where the edges of each floorboard are slightly higher than the middle.

In short, moisture. It can still react with the moisture content MC in the air around it. Materials like wood will balance equilibrate its MC with its surroundings, similar to the principle of osmosis. So if the air is humid, the wood will absorb more moisture from the air and it will swell. If the air is dry, wood fibers will release some of its moisture back into the air and it can shrink back down.