Flooring Advice
Underlay affects how your floor feels, how warm it is, how quiet it is, and how long it lasts. Getting it right is not complicated — but getting it wrong wastes money and compromises the whole installation.
Why Underlay Matters
Most people think of underlay as a soft layer that makes the floor feel less hard underfoot. That's part of it. But good underlay does much more than that.
It provides thermal insulation — keeping feet warmer and reducing heat loss through the floor. It gives acoustic damping — reducing the hollow sound of footsteps and the transmission of impact noise to floors below (critical in flats and upper-floor rooms). It creates a moisture barrier on concrete subfloors where damp is a mild concern. And it cushions the floor against micro-movement and impact stress, which reduces wear on the locking joints and extends the life of the floor.
A cheap floor over quality underlay often outperforms a quality floor over cheap underlay. It's the component most people overlook and most regret skimping on.
Insulates against cold subfloors. Keeps feet warmer in winter.
Reduces impact sound — footstep noise and transmission to floors below.
Integrated DPM film options for mild damp on concrete subfloors.
Cushions joints against stress. Extends the lifespan of the floor above.
Underlay Types
Not all underlays are the same. Here's what's available and where each one is the right choice.
The cheapest option. Adequate for laminate in low-traffic, dry rooms at the lower end of the budget. Poor acoustic performance. Compresses relatively quickly. Not suitable for heavy use or as a moisture barrier. Fine for a spare bedroom — not what we'd choose for a hallway or living room.
Made from recycled rubber. Excellent acoustic performance — noticeably better than foam at reducing impact sound. Dense and durable — doesn't compress as quickly. Good for LVT and laminate in living rooms, hallways and upper-floor rooms where acoustic performance matters. Heavier than foam but worth it.
Traditional choice. Good thermal and acoustic properties. Dense and stable. Used under engineered and solid wood floors where a more rigid base is preferred. Also used where a floating installation calls for a firmer feel underfoot rather than a springy one.
Premium option for flats, upper floors, or anywhere noise transmission to the floor below is a concern. Dramatically reduces impact sound — the difference is genuinely noticeable. More expensive, but cheaper than a neighbour complaint or a lease dispute. We always recommend this in flats.
Foam underlay with an integrated polyethylene DPM film on the underside. Useful on concrete floors where moisture readings are marginal — not high enough to need a separate membrane, but worth addressing. Removes the need for a separate DPM layer on mild cases.
Many LVT products come with underlay already bonded to the underside of the plank. This is convenient and works well, but: always check it is UFH-rated if you have underfloor heating, and don't add additional underlay on top — it will cause the locking joints to flex and fail.
Underlay by Floor Type
Different floor types have different requirements. Using the wrong underlay can void a manufacturer's warranty — or worse, cause the floor to fail.
| Floor Type | Recommended Underlay | Key Considerations |
|---|---|---|
| LVT (no pre-attached) | Thin rubber or specialist LVT underlay (1.5–2mm) | Do not use thick foam — LVT needs a firm, stable base |
| LVT (pre-attached) | None — pre-attached only | Check it's UFH-rated if you have underfloor heating |
| Laminate | Foam or rubber crumb (2–3mm max) | Never exceed 3mm — thicker underlay causes joint failure |
| Engineered Wood (floating) | Felt or rubber; check manufacturer spec | Some products specify a particular underlay — always check |
| Solid Wood (glued/nailed) | Usually none — glued directly to subfloor | Some floating solid wood uses felt; specialist advice needed |
| Parquet (adhesive) | None — adhered directly to subfloor | Subfloor must be perfectly level and dry |
Underfloor Heating
If you have underfloor heating, underlay selection is critical. The wrong underlay will insulate against the heat — meaning your UFH system has to work harder, costs more to run, and heats the room less effectively.
The key measure is tog rating — the thermal resistance of the underlay. For underfloor heating, you want a tog rating as low as possible. Generally under 0.15 tog for underlay with UFH. Some manufacturers specify even lower.
Things to check:
We check all of this at the consultation stage. If your home has UFH, tell us — it affects which products we recommend.
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Every installation includes the right underlay for your floor type, your subfloor and your household. We don't leave this to chance — and we include it in the quote from the start.
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