Wood Floor Cupping

Wood floor cupping is a common problem that occurs with both solid and engineered wood floors.

Wood floor cupping.

Wood is hygroscopic in nature and thereby tends to absorb moisture from its surroundings causing problems in hardwood floors. It ends up looking a little like an accordion. See the picture at the top of this post for an example of a cupped floor. Other causes of hardwood floor cupping could include situations such as basement plumbing leaks that allow moisture to migrate up into the subfloor and into the wood flooring or the heat from a wood stove that drys out the air in the environment.

This makes the wood appear to be in a u shape. If you imagine a picture of a child drawing a boat in the water then the water will give you a good idea of what a cupped floor looks like. A cupped floor has a concave shape across the width of the boards. Moisture from below can.

Cupping occurs in solid wood flooring as a result of an elevated mc in the bottom of the flooring compared with the mc of the face. The paper will curl up away from the water. As you can see moisture and wood don t go well together. If you think you can escape cupping by installing a bamboo or laminate floor you can t for they can also cup.

Cupping means that the wood that is raised on the edges of each individual floor board. It can happen to most types of wood and it s often the first observable sign your floor is being affected by moisture. Cupping can also occur in rooms with dry humidity. Increase the relative humidity in the room with cupped floors to 20 percent to prevent cupping from the air being too dry.

Cupping in hardwood floors is caused by changes in moisture levels whether decreases in the air rh above or increases in moisture from below. It is not hard to see the effect in wood flooring either. The general effect is easy to demonstrate by putting a small strip of paper onto a small drop of water. The center of the board dips below the edges.

Cupping is one of the unfortunately common issues that can plague hardwood floors. The simplest way to think of wood floor cupping is to imagine the edges of each plank sticking up higher than the centers.