SPC Flooring Gaps and Buckling: 9 Major Causes & Preventive Solutions

SPC flooring is widely popular thanks to its rigid core and reliable dimensional stability. However, gaps, buckling, curled edges, and disengaged click-lock joints may still appear after installation. Such failures are mostly caused by high temperature, limited expansion space for flooring, poor on-site base conditions, broken click locks, or inconsistent product quality.
For importers, distributors, engineering contractors, and buyers of commercial projects, simply replacing planks without identifying the root cause often only achieves a temporary fix. Troubleshooting requires a full assessment of the entire flooring system, including the product itself, subfloor, installation layout, and indoor environment. This article sorts out nine common triggers for SPC flooring expansion, contraction, and buckling, and provides on-site inspection points before installation or repair. Surface symptoms alone cannot determine whether the problem arises from product defects, improper installation, or site environmental factors. Preserve on-site records and fully inspect the whole flooring system before repairs.

1. Direct Sunlight and High Local Surface Temperature
SPC flooring laid beside large glass windows or glass doors continuously receives solar radiation, and the local temperature can be much higher than in other indoor areas. Temperature differences trigger expansion and contraction deformation of planks. Once planks are blocked by walls, thresholds, columns, or other hard structures, the floor will buckle and bend, imposing extra stress on click-lock joints.
For large commercial projects, evaluate the direction and duration of direct sunlight, glass parameters, fluctuations of floor surface temperature, supporting shading solutions such as blinds, curtains or solar control films, reserved perimeter expansion gaps, and strictly follow the manufacturer’s installation specifications. Measuring only room temperature cannot detect hidden risks. When buckling occurs, make sure to measure the floor surface temperature near windows.

2. Insufficient Reserved Expansion Gaps for SPC Flooring
Floating SPC flooring requires adequate expansion gaps around walls and fixed structures. The required gap width is determined by product model, room size, installation layout, and manufacturer requirements. Gaps shall be reserved along walls and skirting boards, door frames and thresholds, columns, floor penetrations, fixed cabinets, partitions, and large connected flooring zones. A common hidden risk: gaps reserved during installation get blocked later by skirting boards, sealant, screws, or fixed components. Installed flooring must retain space for free expansion and contraction. Re-measure the perimeter expansion gaps before fitting skirting boards.

3. Floating Flooring Trapped by Fixed Cabinets
Floating SPC flooring must not be locked in place by permanent cabinets, countertops, partition walls, or other fixed structures. When expansion of a large flooring area is restricted, stress will concentrate locally and result in buckling or separated joints. Before construction, coordinate the flooring layout with cabinet and decoration plans, clarify the flooring termination positions, and install fixed structures independently. Heavy movable furniture differs from permanent fixed structures. Nevertheless, concentrated loads and improper furniture feet can still damage the plank surface and seams, which should be considered at the project planning stage.

4. Lack of Transition Design for Large-Area Installation
Projects such as hotels, office buildings, schools, retail stores, and apartments often feature long corridors and connected large open spaces. Continuous large-area floating flooring installation accumulates internal stress. Before cutting materials, confirm the total installation area, room layout, doorways, and corridor directions, fixed components including columns and cabinets, temperature zones with different sunlight exposure, define the position and specifications of transition profiles in advance, and comply with the manufacturer’s installation length limits. Transition plans should be finalized before material cutting. Rectifying improper layout after installation is more difficult and costly.

5. Uneven or Unqualified Subfloor
An uneven subfloor does not directly trigger every expansion issue, but unsupported areas shift under foot traffic and continuously pull click-lock joints, causing squeaking, separated plank ends, curled edges, or damaged locking profiles. Subfloor inspection covers overall flatness, local high and low spots, surface strength and cleanliness, crack repairs, moisture content, and residual debris. Thicker SPC planks or soft underlay cannot replace proper subfloor levelling. Concrete subfloors must be inspected and levelled prior to SPC flooring installation.

6. Damp Substrate and Unqualified Site Conditions
The SPC stone-plastic core itself is waterproof, but this does not mean the full flooring system can be installed directly on damp, unprepared substrates. Subsurface moisture erodes the base, underlayment and surrounding building materials. Resolve water leaks, wet screeds and other substrate defects before installation. Moisture testing standards shall follow project specifications, local construction codes and manufacturer instructions. Waterproof flooring and proper site preparation are separate matters. Buyers should not treat SPC flooring as a solution for unresolved substrate moisture problems.

7. Improper Storage and Inadequate Site Acclimation
If flooring is stored in extremely hot, cold, or exposed locations, planks will arrive on-site at temperatures drastically different from indoor conditions. Planks may also deform when cartons are stored upright without support.
Before installation: store cartons flat and stably; protect flooring from sun and rain and avoid extreme warehouse and on-site temperatures; deliver planks to the construction site in advance for environmental acclimation following the supplier’s temperature & humidity conditioning requirements; inspect outer packaging and sample boards before opening packages. For export orders, control storage conditions throughout factory warehousing, container loading, ocean shipping, and destination warehouse storage.

8. Damaged Click Locks or Improper Installation Operations
Gaps between planks are not always caused by shrinkage of the SPC core. Repeated stress from uneven subfloors may damage locking profiles or lead to incomplete joint engagement.
Common click-lock installation faults: joining planks at an incorrect angle, applying excessive force during installation, using planks with damaged locking profiles, dust and debris trapped inside joints, incomplete full-length plank engagement, and continuing installation after joint defects appear. Pay close attention to the first completed row of planks. Early alignment errors affect subsequent installation and become hard to remedy later.

9. Insufficient Raw Material and Production Stability
Dimensional stability depends on SPC formulation, raw material purity, extrusion process, cooling procedure, and dimensional tolerances. Flooring manufactured by different factories or of different quality grades varies in performance and cannot be treated equally.
Before bulk order approval, buyers shall verify product structure (thickness of SPC core, wear layer, decorative film, and backing), core and finished plank thickness, plank length, width, and tolerances, click-lock precision, check the texture, color, and structure of approved samples, and confirm QC protocols, batch control, and test reports. Bulk delivered products must conform to approved samples, quotations, and purchasing specifications.