Can All Hardwood Flooring Be Dried?
Cupping has occurred when the sides of flooring 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.
Unfortunately in almost all cases, glued-down engineered flooring will need to be cross cut with a circular saw and completely removed and new flooring installed.
For this article we’ll discuss the dynamics of only Solid Wood such as the 2″ solid wood planking in the photo above. The driving force for cupping comes from a response of the wood to a change in moisture content (MC). Usually from flooding water either from a broken pipe, overflowing appliance or rising water. Below the Fiber Saturation Point (typically 28% to 30%), wood swells if the MC is increased and shrinks if the MC is decreased. The mechanism that causes swelling can be understood by looking at the cellular structure and organization in wood.
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 surface.
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, in this case the source of water in the photo’s in this article came from the rising water as a result of coastal surge from Hurricane Matthew in North Florida.Prior to the hurricane, the Moisture Content (MC) of the wood floors had an equilibrium value based on the RH of the air. When the MC increased due to the saturation, the wood swelled, just as it always does when liquid water is introduced.
A solid wood floor that has water introduced to it from the bottom 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 such as the ones found in this property. 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 will dry out more slowly but this can be beneficial for a heated drying process.
As wood responds to environmental changes, the boards in a floor can experience forces from adjacent boards and from the sub-floor. When increasing MC causes a board to expand, the rest of the floor pushes back and restricts the swelling to some extent. Wood has an elastic property in response to a force applied to it. If a board is bent a small amount, it will go back to the original shape when the bending force is removed. Similarly, wood constrained from swelling (in the range where the size would have changed less than one percent) returns to the original size when the MC returns to the initial value.
On the other hand, if the MC increases enough while the wood is not allowed to swell by adjacent boards, it acquires a set and will not go back to the initial size when brought back to the original MC. This is called “compression set.” The result is gapping between boards when the floor is dried because the boards are narrower. If you hit a board with a hammer lightly, it bounces with no damage. A hard hit will cause a dent. In severe cases, floors that have been at an elevated MC may experience compression set and have permanent gaps between the boards. Set can often be reversed by treating with steam, but this is not a viable solution for an installed floor.
Negative Pressure Floor Drying Technology
Technology allows professional restoration companies to FORCE water out of wood through negative high pressure (also known as vacuum) that provides suction from the base of planking between base and sub-floor. Dry It Fast water damage company utilizes the patented Injectidry vac panel system.
With the use of heat and vacuum systems we are able to force water moisture out of wood and into the ambient air space thereby helping to return wood planks to an equilibrium within the room space.
See Video Below…