Why Does Water Damage Make Floors Buckle?

Most floors are made of materials that react to moisture. Solid hardwood is porous, so water seeps into the wood fibers and makes them expand. Laminate has a fiberboard core that soaks up water quickly, swelling and separating from its protective top layer.

Engineered wood has a thin real-wood veneer over a plywood base, and that base can also absorb water. When the planks swell, they press against each other and against the walls. Since there is no room to expand sideways, the floor lifts upward, creating the buckled, wavy look you see.

Solid hardwood buckles when it absorbs water, but it often dries back to a flatter shape if the moisture is removed quickly. Laminate, however, tends to swell permanently because its fiberboard core does not return to its original size once wet.

Engineered wood sits between the two, but it can still warp and delaminate if water sits too long. Vinyl and tile are more water-resistant, but water can still seep underneath and cause the subfloor to swell, which pushes the surface up.

If the buckling covers a large area, or if the water has been there for more than a day, professional help is often the right step. The pros can assess how far the moisture has spread and use industrial dehumidifiers to dry the subfloor properly.

They can also determine whether the flooring can be saved or needs removal. In many cases, drying the subfloor and replacing damaged planks is more practical than trying to flatten a badly warped surface. The pros will explain what the work usually involves before starting.

• Large buckled sections that cover most of a room
• Water that came from flooding, sewage, or unknown sources
• A musty smell that lingers after drying
• Subfloor that feels soft or spongy under the buckled area
• Buckling that appears in multiple rooms at once