Timber Floor Cupping

Moisture from below can.

Timber floor cupping.

As the name implies the surfaces of boards that suffer from cuppinghave a concave shape. The center of the board dips below the edges. The general effect is easy to demonstrate by putting a small strip of paper onto a small drop of water. The cupping is due to some type of moisture imbalance in the wood flooring itself.

Wet crawlspaces and basements will cup a floor as moisture moves upward. Leaks in pluming systems and fixtures sink dishwasher icemaker and toilet overflows. Cupping dry or wet wood floors can be caused by humidity lack of humidity temp water. Wood cupping develops a set in boards ultimately boards that have cupped due to these moisture differences develop a set and remain cupped even when the boards have dried.

The sides of each board are higher than the middle sections. Wet maintenance can cause cupping. Cupping in solid wood floors. When the moisture increases the wood swells and then when it decreases the wood shrinks.

Cupping can also occur in rooms with dry humidity. Wood is hygroscopic in nature and thereby tends to absorb moisture from its surroundings causing problems in hardwood floors. It is not hard to see the effect in wood flooring either. 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.

Cupping means that the wood that is raised on the edges of each individual floor board. You can observe this dramatically in an interior wood floor that has been flooded then dried. Any wood floor can suffer from cupping. See the picture at the top of this post for an example of a cupped floor.

Boards will remain cupped. Cupping is a result of the changes in moisture in the room. Cupping is a common problem found in hardwood floors. 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.

As you can see moisture and wood don t go well together. The paper will curl up away from the water. The simplest way to think of wood floor cupping is to imagine the edges of each plank sticking up higher than the centers. It ends up looking a little like an accordion.

This makes the wood appear to be in a u shape. Site related causes of wood floor cupping. Water vapor emissions from concrete. This imbalance could either be moisture from the concrete environmental conditions in the space being to dry and drying out the top of the wood and or a wood floor that wasn t properly acclimated to the environment prior to installation.

How our 950 moisture meter works is it has a hygrometer built in to read temp humidity and calculates your the emc equilibrium moisture content of what your wood floor should be. Wood is hygroscopic so it gains or loses moisture in your home seasonally.