Warping or bowed flooring

My floor is warping after installation

"Cupping and crowning" are common complaints that develop with high humidity or moisture levels commonly described as warping.

Both problems occur across the width of the flooring material.

Cupping is when the edges of a board are high and its centre is lower. It only occurs after water or moisture is absorbed into the wood from beneath, normally from the sub floor conditions. Cupping is caused by a moisture imbalance through the thickness of the wood. The wood is wetter on the bottom of the board than on the top.

Taking moisture meter readings can prove the moisture imbalance.

The first step in repairing a cupped floor is to identify and eliminate the moisture source. Once the source of the moisture is controlled, cupping can usually be cured. The floor may improve on its own as it dries out over time. Alternatively you can try and accelerate the drying process by using dehumidifiers. Once the moisture content has stabilized, the floor can be reassessed.

Crowning is the opposite of cupping: The centre of a board is higher than the edges.

Moisture imbalance is again the cause of the crowning however, the excessive moisture is introduced on the top of the floor and not from beneath, perhaps from water used in maintenance. The end result and problem solving is the same as cupping. The determination of moisture content is an essential part of the flooring installation process.

Flooring installers must know the dryness of the concrete slab and should not accept the sub floor is ready for installation based on just the age of the slab. Moisture readings are essential before installation takes place.

It is equally important to check percentage of relative air humidity, and acclimatising the material before installation.

My flooring is warped / bowed before installation

Bowed flooring is common and therefore a certain amount of bowing is to be expected in any wood flooring board. Engineered and solid wooden flooring products are produced in controlled conditions and when packaged for distribution, contain moisture content of approximately 8% - 12%. Our installation instructions state that the boards must not be unwrapped until they are required.

The reason for this is to allow the moisture content of the boards to adjust to changes in relative humidity as a complete floor. Staggering the joints during installation is necessary to maintain the structural integrity and eliminates any deformities caused by exposure to moisture. This in turn keeps the flooring flat and fully supported. Bowing to a degree, is not considered a defect in any wood component, and does not indicate a faulty product nor does it affect the ‘quality’ of the finished floor.

All this information should be documented before installation is carried out.