When it comes to refreshing your home with new carpet, it’s easy to get swept up in colors, textures, and styles. But before you roll out that plush new carpet, there’s one often-overlooked hero you need to consider first: carpet underlay.

A quality underlay isn’t just a bonus—it’s essential. It can dramatically improve the comfort, longevity, insulation, and even the appearance of your carpet. So, what should you be looking for when choosing the perfect underlay?

Let’s break it down.

1. Material Type: Know What You’re Walking On

Underlay comes in a variety of materials, each with its pros and cons:

  • PU (Polyurethane) Foam: Lightweight, soft, and made from recycled materials. It’s a popular choice for domestic use thanks to its comfort and insulation.

  • Rubber (Crumb or Sponge): Durable and dense. Crumb rubber is great for high-traffic areas, while sponge rubber offers a more cushioned feel.

  • Felt: Traditional and made from recycled fibres. Offers excellent sound insulation but tends to be less soft than foam.

  • Combination Underlay: Some modern products combine felt and rubber to get the best of both worlds.

💡 Tip: If sustainability is important to you, look for underlays made from recycled or eco-friendly materials.

2. Thickness and Density: Comfort Meets Durability

  • Thickness typically ranges from 6mm to 12mm. Thicker underlays add more cushioning, but thicker isn’t always better—too much padding under certain carpets can cause instability.

  • Density is measured in pounds or kilograms per cubic meter. Higher density means more support and longer-lasting performance, especially in busy areas like hallways and stairs.

🎯 Ideal Choice: Around 8-10mm thick with a high density for most living spaces. For stairs, go slightly thinner (like 8mm) to ensure the carpet hugs the steps tightly.

3. Thermal and Acoustic Insulation: Keep It Cozy and Quiet

A good underlay provides insulation against both temperature and sound. This is especially important in flats or upstairs rooms.

  • TOG Rating indicates thermal insulation. Higher TOG means better warmth retention—great for bedrooms and living rooms.

  • Sound Reduction helps minimize footsteps and general noise, particularly useful in multi-storey homes or apartments.

🔇 If peace and warmth matter, go for an underlay with a high TOG and decibel reduction rating.

4. Moisture Protection: Don’t Let Damp Creep In

In areas like basements or rooms with concrete subfloors, moisture can be an issue. Look for underlay that includes a moisture barrier or damp-proof membrane (DPM).

🛑 Skipping this step can lead to mold, odors, and damage to both underlay and carpet.

5. Room Suitability: One Size Doesn’t Fit All

Different rooms call for different underlay needs:

  • Living rooms/bedrooms: Comfort-focused foam underlay.

  • Hallways/stairs: Dense rubber underlay for durability.

  • Kitchens/basements: Moisture-resistant underlay.

  • Underfloor heating: Special low-TOG underlay designed to allow heat to pass through efficiently.

📍 Always match the underlay to the function of the room.

6. Budget vs. Value: Spend Smart, Not Cheap

Yes, it can be tempting to save on underlay—but it’s not the place to cut corners. A high-quality underlay can extend the life of your carpet, improve comfort, and save on energy bills.

💸 Think of it as a long-term investment in your home’s comfort and durability.