What plank thickness should I choose in SPC (4mm vs 5mm vs 6mm)?

Plank thickness in SPC is the second most-discussed spec after wear layer, and is often misunderstood. Thickness affects acoustic comfort, subfloor tolerance, and underfoot feel - but it does NOT determine scratch resistance, which is a function of the wear layer.

WHAT PLANK THICKNESS ACTUALLY AFFECTS:

1. SUBFLOOR TOLERANCE. A thicker, stiffer plank bridges minor subfloor dips and bumps that a thinner plank would telegraph through. 4mm SPC needs an almost-perfect level subfloor (within 2mm variation over 1 metre). 5-6mm SPC tolerates 3-4mm variation. 8mm+ tolerates 5mm.

2. ACOUSTIC PERFORMANCE. Thicker planks (with their attached IXPE underlay) dampen footfall noise. A 5mm SPC sounds noticeably quieter than 4mm; 6mm is quieter still. Important on upper floors where downstairs occupants will hear footfall.

3. UNDERFOOT FEEL. Thicker planks feel more "solid" and less hollow underfoot. Some buyers prefer the firmness of 4mm; most prefer the substantial feel of 5-6mm.

4. DOOR CLEARANCE. Thicker planks raise the finished floor level more, requiring more door bottom trimming. Standard hinged doors need 8-15mm clearance over the finished floor.

WHAT PLANK THICKNESS DOES NOT AFFECT:

Scratch resistance - that's wear layer.
Water resistance - all SPC is waterproof regardless of thickness.
Print quality - independent of plank thickness.
Click-joint strength - modern Unilin/Valinge click systems work across all thicknesses.

THICKNESS TIERS AND USE CASES:

1. 4mm - BUDGET OR RIGID-SUBFLOOR INSTALLS.
Use when: budget is tight, OR you're laying over existing tile/marble that's near-perfectly flat. Cheapest option.

2. 5mm - STANDARD RESIDENTIAL (THE DEFAULT).
This is the recommended default for most Indian homes. Hides minor imperfections, sensible acoustic feel, fits standard door clearance assumptions. 80% of SPC we sell at Material Depot is 5mm.

3. 5.5-6mm - PREMIUM RESIDENTIAL.
Best acoustic performance - noticeably quieter footfall, important on upper floors of duplex or apartment buildings. Hides up to 4-5mm subfloor variation. More substantial underfoot feel.

4. 8mm+ - ULTRA-PREMIUM / IMPORTED.
The luxury European ranges. Best-in-class everything. Highest cost.

DOOR CLEARANCE PLANNING:
Total floor height rise = plank thickness + underlay thickness (1-1.5mm if using separate underlay) + adhesive (if any). For a 5mm SPC with attached IXPE, total rise above subfloor is ~5mm. Add to that the existing subfloor level vs door bottom, and most installs need 8-15mm trimmed from door bottoms before re-fitting.

THICKNESS + WEAR LAYER MATRIX (what to actually pick):
Bedroom in rental: 4mm with 0.3mm WL.
Standard family home, living + bedrooms: 5mm with 0.5mm WL.
Premium home, upper floors: 5.5-6mm with 0.5mm WL.
Kitchen heavy use: 5mm with 0.5-0.7mm WL.
Light commercial: 5mm with 0.7mm WL.
Imported luxury feature room: 8mm with 0.5mm WL.