5.5mm Thick Luxury Vinyl Flooring
5.5mm typically includes an attached acoustic underlay — a thin foam or cork layer bonded to the back of the board that improves sound absorption and provides a softer underfoot feel. This format is popular on retrofit projects over timber floors where acoustic improvement is valued, and in upper-storey apartments where sound isolation matters. 5.5mm with underlay is easier and cheaper to retrofit than layering a separate underlay under 5mm rigid-core.
5.5mm is the sweet spot for retrofit where you want the thick-core benefits of 5mm plus built-in acoustic help, without stepping into the 6–8mm territory. See samples at the 24/7 smart-lock Altrincham showroom or request a same-day quote with your existing floor details and room layout.
What Does 5.5mm With Underlay Mean?
5.5mm is the total thickness including an attached acoustic underlay, typically 1–2mm of foam or cork bonded to the back of the board. The core beneath is 2–2.5mm of rigid material, and the wear layer is 0.3mm or more on top. The underlay is factory-bonded, so it does not separate during installation — the entire assembly is one structural unit. This approach gives you acoustic benefit without the complexity of installing a separate underlay layer.
5.5mm in the Thickness Ladder
5.5mm sits between pure 5mm rigid-core and the 6mm+ formats where underlay becomes thicker or where boards ship with separate underlay components. For retrofit projects where acoustic performance is important, 5.5mm with attached underlay is the most straightforward choice.
Installation Format: Click-Lock with Attached Underlay
5.5mm with attached underlay is click-lock and floating. The integrated underlay means you do not need to buy and install a separate underlay layer — the board includes it. Installation is straightforward: lay the boards with click-lock edges, and the underlay provides both sound absorption and a cushioning layer. Retrofit capability is excellent over timber, concrete and tile.
Underfloor Heating Compatibility
5.5mm with underlay is marginal for underfloor heating — the attached underlay provides insulation that slows heat transfer. If UFH is important, use glue-down formats or thin rigid-core without attached underlay. Check with the manufacturer before specifying.
Thickness Does Not Determine Durability — Wear Layer Does
**The attached underlay improves comfort and acoustic performance; the wear layer determines durability.** Most 5.5mm options carry a 0.3mm wear layer — the same proven spec used on thinner boards. The underlay does not affect wear resistance. Compare wear-layer specs when comparing 5.5mm options. Read our 0.3mm wear layer guide.
Explore Related Categories
- Thickness ladder: 5mm, 6mm, 6.5mm, 8mm.
- By install format: click LVT, loose lay LVT.
- By wear layer: 0.3mm, 0.55mm.
- By brand: Invictus, GF LVT.
- Wider context: back to luxury vinyl flooring.
How to Buy or Get a Quote
Contact us via enquiry form, WhatsApp or phone with your shortlist and floor details, and we will come back the same working day. Supply-and-fit available across Cheshire and South Manchester from our 24/7 smart-lock Altrincham showroom.
