Introduction
Underlay is one of the most important — and most overlooked — parts of any flooring installation. Get it right and your floor will feel better, sound quieter, last longer, and perform more efficiently with underfloor heating. Get it wrong and you could void your flooring warranty, cause premature wear, or end up with a floor that sounds hollow and feels uncomfortable underfoot.
The key rule: underlay is not one-size-fits-all. The right underlay depends entirely on your flooring type, your subfloor, and your specific requirements. This guide breaks it down clearly for the three most common flooring types we sell: laminate, LVT, and carpet tiles.
Do I Need Underlay for Laminate Flooring?
Yes — always. Laminate flooring must never be laid directly onto a hard subfloor without underlay. Underlay serves four critical functions for laminate:
- Sound reduction: Laminate can sound hollow and clicky underfoot without underlay. A good foam or combination underlay absorbs impact noise significantly.
- Thermal insulation: Underlay adds a layer of warmth, particularly on concrete ground floors.
- Subfloor smoothing: Underlay helps bridge very minor undulations in the subfloor (though it is not a substitute for proper levelling).
- Moisture protection: On concrete subfloors, a vapour barrier layer is essential to prevent moisture rising through the slab and damaging the HDF core of the laminate.
Browse our Laminate Accessories range for compatible underlays, beading, and finishing strips.
What Thickness of Underlay for Laminate?
For most domestic laminate installations, a 3mm foam or combination underlay is the standard choice. Thicker underlays (5mm+) can feel spongy underfoot and may stress the click joints of the laminate over time — always check your laminate manufacturer's maximum recommended underlay thickness before purchasing.
Underlay for Laminate Over Underfloor Heating
If you're laying laminate over underfloor heating (UFH), choose a low-tog underlay specifically rated for use with UFH. A tog rating of 0.5 or below is typically recommended. High-tog underlays act as an insulator and prevent heat from reaching the floor surface efficiently, increasing your energy costs and potentially overheating the system. Our Laminate Accessories include UFH-compatible options — check product descriptions for tog ratings.
Do I Need Underlay for LVT?
It depends on the product. This is where buyers often get confused, so it's worth being precise:
- Glue-down LVT (such as Tarkett Essence 55 and Decotile): No underlay. These tiles are adhered directly to the subfloor with adhesive. Adding underlay would prevent proper bonding and compromise the installation. The subfloor must be perfectly flat and dry — the tile itself provides no cushioning or levelling.
- Rigid-core LVT (such as Tarkett Essence Rigid 55): Some rigid-core products come with an attached underlay pre-bonded to the back of the plank or tile. If yours doesn't, a thin (1–2mm) foam underlay compatible with rigid LVT can be used. Always check the manufacturer's technical datasheet first — using an unapproved underlay can void the warranty.
- Click LVT / loose-lay LVT: A thin, firm underlay may be recommended. Again, check the product specification.
The bottom line for LVT: when in doubt, check the technical datasheet for your specific product. If it says direct stick, do not add underlay.
LVT and Underfloor Heating
Most glue-down LVT is compatible with underfloor heating provided the surface temperature stays below 27°C. Because there's no underlay between the tile and the subfloor, heat transfer is very efficient — one of the advantages of glue-down LVT over floating floors. Our Tarkett Essence 55 and Tarkett Essence Rigid 55 are both suitable for use with UFH — refer to the product datasheets for full guidance.
Do I Need Underlay for Carpet Tiles?
No — carpet tiles are designed to be laid without underlay. Unlike broadloom carpet, which requires a separate underlay and gripper rods, carpet tiles have their own integral backing that provides cushioning and stability. Adding a separate underlay beneath carpet tiles would make them unstable and prone to movement, particularly at the joints.
Our Avenue and Skyline carpet tiles are both designed for direct installation onto a prepared subfloor, using either a pressure-sensitive adhesive, double-sided tape, or a free-lay method for temporary installations. See our carpet tile installation guide for full details.
Quick Reference: Which Underlay Do I Need?
| Flooring Type | Underlay Required? | Key Considerations |
|---|---|---|
| Laminate (click/floating) | Yes — always | Foam or combination; low-tog for UFH; check max thickness |
| Glue-down LVT | No | Direct bond to subfloor; subfloor must be flat and dry |
| Rigid-core LVT | Sometimes | Check datasheet; may have pre-attached underlay |
| Carpet tiles | No | Integral backing; underlay would cause instability |
Moisture Barriers: When Do You Need One?
On concrete ground floors and screeds, moisture rising from the slab is a real risk — even in buildings that appear dry. For laminate flooring, always use an underlay with an integrated DPM (damp proof membrane) on concrete subfloors, or lay a separate polythene membrane (minimum 250 micron) before the underlay.
For glue-down LVT, the adhesive itself provides a degree of moisture resistance, but if your moisture readings are elevated (above 75% RH or 3% CM), you should apply a moisture suppressant primer to the subfloor before laying. Always carry out a moisture test before installing any flooring on concrete.
Common Underlay Mistakes to Avoid
- Using too thick an underlay under laminate: Can stress click joints and cause the floor to feel spongy and unstable.
- Adding underlay under glue-down LVT: Prevents proper adhesion and will cause the floor to fail.
- Overlapping underlay sheets: Always butt underlay sheets edge-to-edge and tape the joins. Overlapping creates a ridge that telegraphs through the floor.
- Skipping the moisture barrier on concrete: One of the most common causes of laminate floor failure.
- Using a high-tog underlay over UFH: Reduces heating efficiency and can overheat the system.
Shop Flooring Accessories
- Laminate Accessories — underlay, beading, threshold bars, and finishing strips for laminate installations.
- Tarkett Essence 55 LVT — commercial glue-down LVT, no underlay required.
- Tarkett Essence Rigid 55 — rigid-core LVT, check datasheet for underlay compatibility.
- Avenue Carpet Tiles — no underlay needed, direct installation.
- Skyline Carpet Tiles — no underlay needed, direct installation.
Not sure which accessories you need for your project? Contact our team and we'll make sure you order everything you need — and nothing you don't.