Are you planning to install new flooring in your home or office? The success of your project lies not only in the choice of carpet or laminate flooring, but also in the unsung hero of flooring – the carpet underlay. But what exactly is underlay, and why is it so crucial for a comfortable and long-lasting floor?

In this comprehensive guide, we’ll explore the importance of carpet underlay, compare different types, and provide expert tips for choosing, installing, and maintaining the best underlay for your specific needs. Say goodbye to chilly floors, noisy footsteps, and prematurely worn-out carpets – let’s dive into the world of carpet underlay.

Short Summary

  • Carpet underlay provides comfort, insulation, soundproofing and thermal properties which help extend the life of your carpet.
  • Factors such as room type and usage, budget constraints, and compatibility with heating systems should be considered when selecting the best underlay option.
  • Proper installation techniques along with regular maintenance can ensure optimal performance from your chosen carpet underlay.

Understanding the Importance of Carpet Underlay

Carpet underlay is the unsung hero of flooring, performing the dual role of providing comfort and insulation while extending the life of your carpet. A quality flooring underlay can significantly extend the life of a carpet by up to 50%, reduce sound, aid in soundproofing upper-level rooms, and possess thermal and insulation properties.

But what makes underlay such an essential element in flooring? To better understand the importance of carpet underlay, let’s break it down into two key benefits: comfort and insulation, and prolonging carpet life.

Comfort and Insulation

The primary purpose of carpet underlay in terms of insulation is to serve as a barrier, retaining heat and preventing cold from seeping through the floor. One example is PU foam underlay, which is soft and lightweight and offers good insulation and noise reduction, making it a versatile choice. 

For a laminate floor, a suitable laminate flooring underlay is necessary to provide comfort and insulation. Laminate underlay provides additional comfort for your laminate flooring, minimizes flexing, dampens footstep noise, and helps retain warmth in your home. 

When selecting the optimal carpet underlay, it’s important to consider the type and usage of the room, budgetary restrictions, and compatibility with heating systems.

Prolonging Carpet Life

Carpet underlay serves to protect the subfloor and minimize wear and tear on the carpet, ultimately prolonging its life. Wool felt underlay is an excellent example, offering exceptional thermal and acoustic insulation while being very long-lasting, typically outlasting the carpet itself.

To ensure the best results, it’s crucial to follow proper installation procedures when laying underlay on a concrete floor or any other type of subfloor. By investing in a suitable underlay and ensuring proper installation, you can extend the life of your carpet and enjoy a comfortable, well-insulated floor for years to come.

Types of Carpet Underlay: A Comparison

Now that we understand the importance of carpet underlay, let’s explore the different types available and their respective benefits. There are various types of carpet underlay, including sponge rubber, crumb rubber, PU foam, wool felt, and combination underlay. Each type offers unique advantages, making it essential to choose the right underlay for your specific needs and preferences.

In the following sections, we’ll take a closer look at each type of carpet underlay, discussing their strengths and weaknesses to help you make an informed decision for your flooring project.

Sponge Rubber Underlay

Sponge rubber underlay is a popular choice for many flooring projects. It a dense and heavy type of underlay, offering both durability and flexibility. Its resilience makes it suitable for areas with heavy foot traffic, and it also provides excellent insulation and soundproofing properties. However, Its denser and heavier composition may make it more difficult to handle and fit in certain areasit such as stairs. 

Crumb Rubber Underlay

Crumb rubber underlay is composed of up to 85% recycled car tires and other reclaimed rubber-based waste materials, making it an eco-friendly option. This type of underlay is ideal for areas with high foot traffic, as it is very durable and offers excellent insulation and soundproofing properties.

In addition to its environmental benefits, crumb rubber underlay is highly durable, recovers completely from indentations caused by heavy furniture, helps prevent carpeting from rucking, and provides excellent sound insulation and heat retention. Its suitability for high-traffic areas makes it a popular choice for both residential and commercial settings.

PU Foam Underlay

PU foam underlay is an ecologically conscious option, as it is made from recycled furniture foam and other reclaimed foams. It is significantly lighter than rubber underlay and provides excellent insulation for cold floors, sound insulation, and heat retention.

Renowned for its environmental friendliness, PU foam underlay is a lightweight and easy-to-install option that offers excellent performance in terms of insulation and soundproofing. Its sustainable composition makes it an attractive choice for those looking to minimize their environmental impact while enjoying the benefits of a high-quality underlay.

At present, this is probably one of the most commonly used and recommended by floor suppliers and fitters in the UK due to its all round performance. 

Wool Felt Underlay

Wool felt underlay is composed of wool fibers, providing insulation and comfort beneath the carpet. It is known for its durability and resistance to crumbling, making it a long-lasting option. On the downside, this type of underlay can be costlier than other types of carpet underlay and can be unappealing for those who look for luxury because its density makes it feel a little hard underfoot.

Commonly used in commercial structures, wool felt underlay offers excellent thermal and acoustic insulation while also being very long-lasting, making it an ideal choice for high traffic areas. 

Combination Underlay

Combination underlay typically contains a layer of crumb rubber and a layer of wool felt, offering a balance between durability and comfort. It is particularly advantageous in high traffic areas, but can also be used in other areas where both resilience and comfort are desired.

In summary, combination underlay is a highly resilient option that provides superior thermal and acoustic insulation as well as a comfortable walking surface. Its versatility makes it suitable for various applications, both residential and commercial, where a balance between durability and comfort is desired.

Factors to Consider When Choosing the Best Carpet Underlay

With so many underlay options available, it’s important to consider several factors when choosing the best carpet underlay for your specific needs. In this section, we’ll discuss the key aspects to consider, such as room type and usage, budget constraints, and compatibility with heating systems.

By evaluating these factors, you can make an informed decision and select the right underlay for your flooring project, ensuring optimal performance, comfort, and longevity.

Room Type and Usage

The type and usage of the room play a crucial role in determining the best carpet underlay for your needs. For example, a combination (felt/rubber) underlay is the most suitable for a bedroom, as it offers warmth, comfort, durability, and sound reduction.

When selecting the optimal carpet underlay, consider factors such as the volume of foot traffic, the type of activities that will be conducted in the room, and the amount of moisture that may be present. By taking these factors into account, you can ensure that your chosen underlay will perform optimally in your specific setting.

Budget Constraints

Budget constraints are another important factor to consider when choosing the best carpet underlay. When evaluating your budget, take into account the cost of the underlay, the cost of installation, and any supplementary materials that may be required. It’s also important to understand the trade-offs associated with budget options, as cheaper underlays may not provide the same level of comfort or insulation as more expensive options.

By considering your budget and the potential trade-offs, you can make an informed decision on the best underlay for your needs without breaking the bank. Remember that investing in a high-quality underlay now can save you money in the long run by extending the life of your carpet and reducing heating bills.

Compatibility with Heating Systems

Compatibility with your home’s heating system is another crucial factor to consider when choosing the best carpet underlay. The type of heating system, the type of underlay, and the manufacturer’s instructions for installation should all be taken into account.

For example, when using underfloor heating, the maximum combined tog rating for carpet and underlay should not exceed 2.5 tog. By ensuring that your chosen underlay is compatible with your heating system, you can prevent potential damage and optimize the performance of both your flooring and heating system.

How to Install Carpet Underlay

Proper installation is key to ensuring that your carpet underlay performs optimally and provides the desired benefits. In this section, we’ll provide a step-by-step guide to installing carpet underlay, covering important aspects such as preparing the floor and laying the underlay correctly.

By following these guidelines, you can ensure the successful installation of your carpet underlay and enjoy the benefits of a comfortable, well-insulated, and long-lasting floor.

Preparing the Floor

Before laying carpet underlay, it’s essential to properly prepare the floor. Start by ensuring the subfloor is smooth, completely clear from and dirt and grims, and free from nails or staples that may have been left behind from any prior carpeting. If installing carpet underlay over wooden floorboards, note the direction of the boards, as the underlay should be laid in the opposite direction to prevent any “joint-on-joint” occurrences.

Additionally, if you’re installing underlay for laminate flooring, make sure the surface is adequately prepared before fitting the underlay. By taking the time to properly prepare the floor, you can ensure a smooth and successful installation.

Measure your room accurately

Just like any flooring fitting, you have to measure your room accurately to get enough materials to cover your entire floor. If you have a perfectly square or rectangle room, you can simply multiply the the width by the length. Don’t forget to add an extra 50 – 100 mm for each edge. If your rooms is not in a perfect square or rectangle shape, or has any recessions, you can measure each individual areas then add together all the measurements to get the total area of the room.   

Laying the Underlay

When it comes to laying the underlay, begin by laying floor lining paper in rows across the floor area. To avoid the floor ling paper to move around, you can use a duct tape or spray adhesive. Ensure the underlay is oriented correctly by laying it with the right face facing upwards. Secure the end of the first row with staples, and stretch the underlay before affixing subsequent rows with either staples or adhesive. If you lay your underfloor on top of a concrete subfloor, you can use adhesive glue.

For rubber underlay, position the rubber against the floor and the backing facing upwards. For foam underlay, position the coloured film on the floor and the backing facing upwards.

By following these guidelines and paying close attention to the manufacturer’s instructions, you can ensure that your carpet underlay is laid correctly and performs optimally.

Common Underlay Mistakes to Avoid

To ensure the success of your flooring project, it’s important to be aware of common underlay mistakes and how to avoid them. One such mistake is using duct tape instead of underlay tape, which can cause the underlay to shift over time.

Another common mistake is not leaving expansion gap when installing the underlay. Expansion gaps allow for variations in flooring caused by temperature and humidity, preventing potential damage or warping. Our tips is you can leave 10 – 12 mm expansion gap around the room perimeter.

By being aware of these common mistakes and taking steps to avoid them, you can ensure the longevity and performance of your carpet underlay.

Expert Tips for Maintaining Your Carpet Underlay

Maintaining your carpet underlay is essential to keep it looking and feeling as good as new. One expert tip is to invest in a cleaning kit specifically designed for your type of flooring. This will help you maintain the appearance and performance of your underlay, ensuring it lasts for years to come.

Another useful tip is to use door thresholds to join laminate-to-laminate or carpet-to-laminate at doorways, providing a complete and polished look. By following these expert tips, you can keep your carpet underlay in top condition and enjoy the benefits of a comfortable and well-insulated floor.


In conclusion, carpet underlay is a crucial component of any flooring project, providing comfort, insulation, and prolonging the life of your carpet. By understanding the different types of underlay available and considering factors such as room type and usage, budget constraints, and compatibility with heating systems, you can make an informed decision and choose the best underlay for your specific needs.

With proper installation and ongoing maintenance, your carpet underlay will not only support and protect your flooring, but also enhance the overall comfort and warmth of your home. So, take the time to invest in the right underlay and enjoy the benefits of a well-insulated, long-lasting, and comfortable floor.

Frequently Asked Questions

What is the best type of carpet underlay?

For a combination of comfort and durability, the best type of carpet underlay is felt/rubber underlay, which combines the properties of two materials. Felt provides warmth and cushioning, and recycled rubber brings sound reduction and longevity.

What is the best thickness for carpet underlay?

The best thickness for carpet underlay is between 7mm and 12mm; this thickness provides a good balance of cushioning and support to ensure that your carpet will last for many years.

It is important to choose the right thickness of underlay to ensure that your carpet will last for many years. The right thickness will provide the cushioning and support needed to keep your carpet looking and feeling great.

Is expensive carpet underlay worth it?

With the right underlay, you can add extra comfort to your carpets, reduce noise, and even extend their lifespan. If you invest in a good quality underlay, it could be worth the extra expense. Ultimately, the decision is up to you.

In conclusion, investing in expensive carpet underlay may be beneficial due to added insulation, extra comfort, noise reduction, and increased lifespan. The decision ultimately comes down to your preferences and budget.

What are the different grades of underlay?

Underlay comes in a variety of grades, ranging from thin foam mats to thickly padded rubber-backed carpeting. From the thinnest foam matting to the thickest rubber-backed carpeting, there is an underlay grade to suit any floor covering.

Ultimately, it’s important to select the right underlay grade for your needs and budget.

What is the best underlay to use on stairs?

For staircases, foam underlay is the best option as it is lightweight, easy to fit and provides insulation, noise reduction and a soft feel. It is the most versatile type of underlay available and perfect for difficult areas such as staircases or hallways.

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