Why SPC Flooring Warps and Deforms Common Causes Explained
SPC flooring is marketed as dimensionally stable and waterproof. But under certain conditions, it can warp, buckle, or deform. Understanding the causes helps you prevent problems before they happen. Most issues come from three sources: moisture, subfloor condition, and expansion gaps.
Cause 1 Moisture From the Concrete Subfloor
SPC core is waterproof. The plank itself will not absorb water. But moisture vapor rising from the concrete subfloor can get trapped between the concrete and the plank. This trapped moisture creates pressure against the bottom of the plank over time.
The result is edge warping. The plank edges curl upward because the moisture pushes against the underside. In severe cases, the plank loses flatness completely.
This is the most common cause of SPC deformation that gets misdiagnosed as product defect. The plank is not defective. The subfloor moisture was not managed.
Prevention: Use a moisture barrier underlayment between the concrete and the SPC. Test the concrete moisture level with a calcium chloride test or moisture meter before installation. For concrete slabs on grade, the moisture barrier is essential, not optional.
Cause 2 Uneven Subfloor
SPC is a rigid flooring. It does not conform to the subfloor shape. If the subfloor has dips or high spots, the SPC planks bridge over the low areas. The planks are suspended without support underneath.
Foot traffic pushes the plank down at the unsupported area. Over time, the plank flexes repeatedly. This causes the locking mechanism to stress and the plank surface to show visible deformation. Click lock joints may separate at the unsupported area.
Prevention: Check subfloor flatness before installation. The maximum allowed variation is 3mm over a 2 meter span. Use self leveling compound to fill dips. Grind down high spots. A flat subfloor is the foundation of a flat SPC floor.
Cause 3 Insufficient Expansion Gap
SPC expands and contracts with temperature changes. In direct sunlight or near heating vents, SPC warms up and expands. If the planks are installed tight against the walls with no expansion gap, the expanding planks have nowhere to go.
The pressure builds up. The planks push against each other and against the wall. This causes peaking where the planks lift at the seams. In severe cases, the entire floor buckles.
Prevention: Leave the recommended expansion gap around the entire room perimeter. The standard gap is 1/4 inch about 6mm for most rooms. Larger rooms need a larger gap. The gap is covered by baseboards or quarter round trim.
Do not fill the expansion gap with caulk or filler. The gap must remain empty to allow the floor to move freely. The skirting board or baseboard covers the gap visually while keeping it functional.
About PROLEADER
PROLEADER provides installation guidelines for every product to prevent warping and deformation. Contact us for product specific installation requirements and subfloor preparation recommendations.
