Rubber underlay

Underscoring underfoot comfort and quality.


TODAY’s consumers want quality products which offer high levels of comfort and are fit-for-purpose. They’re increasingly concerned with making their money go further and are interested in long-term performance, which is one of the benefits of traditional rubber underlays.

Although the very first underlays were made of felt and used under carpet squares in the 1940s, the development of wall-to-wall carpets in America in the 1950s heralded the introduction of rubber underlays designed to help the carpet sit properly and wear evenly. But the main reason people opted for underlay was for underfoot comfort.

And despite the introduction of PU underlays and their rise in popularity, there’s still nothing quite like a rubber underlay to increase the comfort level of floorcoverings of all types.

Rubber underlays are still widely used in the UK: consumers have never shown any resistance to them as they’re familiar with them. In fact, pound for pound rubber underlays generally deliver better value for money in construction, comfort and durability.

There are two types of rubber underlay: sponge rubber and crumb rubber.

Sponge rubber underlays are one of the most traditional forms of underlay. They have been around since the ‘50s for very good reasons. They’re extremely comfortable: no other underlay produces quite the same feel underfoot. They’re also exceptionally good at minimising impact sound and airborne sound between rooms. They are incredibly flexible and cover more applications than any other type of underlay.

Crumb rubber underlays are, as the name suggests, made from small crumbs of rubber which are bonded together. The rubber crumb comes from used car tyres, so the basic raw material comes from 100% recycled sources. In addition, crumb rubber underlays are fantastically durable and amazing at reducing impact and airborne noise. They are also dimensionally stable with regard to lateral forces. In other words, they don’t stretch or tear easily. Crumb rubber underlays offer outstanding recovery and longevity. This makes them ideal for high traffic and very large areas.

Why choose rubber underlay?
Carpet, as well as wooden and laminate flooring, needs the right type of underlay to make sure it looks great, performs well and lasts longer. The main reason people choose rubber underlay is for underfoot comfort. They also want it to make their flooring last longer, look better and, particularly in the case of hard floorings, to reduce noise and add warmth.
The benefits of rubber underlay include:

  • Makes carpets feel better: provides the cushioning that makes the carpet so comfortable and luxurious underfoot.
  • Makes carpets look better: protects the carpet and helps to prevent the pile from flattening thereby helping the carpet look new for longer.
  • Improves insulation: helps keep in the heat, which will reduce energy bills. Some studies have suggested that underlay can reduce energy costs by up to 15%. Thickness, density and composition dictate the tog rating of underlay which is a measure of heat insulation. The lower the tog rating the better an underlay is for use with underfloor heating because more heat can rise up through the flooring and into the room. Conversely, a higher tog rating gives a greater level of heat insulation which is perfect for use with conventional heating systems.
  • Helps reduce noise: acts as a barrier to sound. A carpeted floor is quiet but a carpet with an underlay can be 2.5 times quieter. Specialist underlays for wood and laminate floors can reduce in-room noise by up to 30%.
  • Makes carpets last longer: acts as a ‘shock absorber’ so carpets suffer less wear.
  • Improves hygiene: protects the carpet pile making it easier to clean and thus more hygienic.

Match the product to the customer’s needs
It’s always better to buy the right underlay to complement the preferred choice of floorcovering and to maximise its performance according to its location. The first question to ask is: what is the flooring’s primary requirement?

Comfort may be a priority in bedrooms and other living areas, while durability is a must in areas such as stairs, halls and landings which see a lot of traffic.

Keeping noise to a minimum might be important for people living in flats, or for those who have young children, or for people who prefer hard flooring, while people with underfloor heating will want an underlay with a very low tog rating.

Comfort underfoot
When it comes to choosing underlay for the home environment, comfort is likely to be a major consideration. More than 70% of consumers say comfort is important to them when it comes to selecting an underlay.

And that’s no surprise. After all, a good quality underlay can make even a budget carpet feel luxurious. This makes it an especially important feature in rooms where people like to relax, such as the lounge and bedroom.

There are several factors that contribute to making an underlay comfortable. These include the ‘sponginess’ of the underlay material, along with its thickness and density. The combination of thickness and density is all important as a thick underlay with low density may not perform well.

Typically, the thicker the underlay, the better quality it will need to be – 11mm is often used for luxury installations with 9mm and 7mm the common domestic thickness, but rooms with heavy traffic will need a thinner, denser pad.

When it comes to modern busy homes, it’s inevitable that some areas experience more traffic than others. These include hallways, where there is a lot of traffic down one narrow path, as well as stairs, where the edge of the carpet on the tread wears quickly. This continuous footfall can unfortunately cause more wear-and-tear to flooring. It’s therefore important choose an underlay that is durable to protect it.

In addition to this, rooms that feature heavy furniture items can also benefit from a durable underlay. This is because it will be more effective in resisting ‘point loading’, which is when heavy furniture causes irritating indentations in carpets. This is common in dining rooms and lounges, where tables, chairs and sofas can cause accelerated wear and tear.

Crumb rubber is the ultimate underlay product when it comes to durability in any application and out-performs all other underlay types.

Reducing noise
Airborne sound can be a constant problem; whether it’s children learning to play drums in their upstairs bedrooms or noisy neighbours, noise leaking from one room into another can completely disrupt the peace and quiet.

The solution is a simple one. Adding mass into a partitioning wall or floor can help to reduce the transmission of airborne sound between rooms. High density sponge rubber and crumb rubber underlays with a combination of both density and thickness, which equates to a mass per square metre, are the ideal choice to keep noise to a minimum.

There are also several other critical factors to consider when fitting the flooring. Noise easily seeps through small cracks, so in order to reduce sound transmissions as much as possible, make sure the underlay and flooring are fitted tightly up to the edges of the walls.

In order to achieve this, it’s best to use a double-stick fitting as opposed to a stretch fit over grippers and make sure that each roll or piece of underlay is tightly butted up to the next one. Tape them together in order to stop any ‘gapping’, which would facilitate the movement of airborne sound.

Impact noise can be a real problem for areas where hard flooring has been installed, and with the current trend towards this type of floor in both domestic and commercial settings, there are now specialist rubber underlays available for use with wood, laminate and luxury vinyl tiles (LVT).

Tests have shown that in-room acoustics can worsen if inferior or lightweight underlays are used with hard flooring; putting a lightweight, air filled, cellular product under wood or laminate creates an echo chamber and more noise, whether it’s generated by scraping furniture, heavy footsteps or reverberation.

Special noise reduction rubber underlays for hard flooring, with their superior weight and density, reduce acoustic noise levels by up to 30%.

Underfloor heating
There are two main considerations when it comes to selecting the right underlay to use with underfloor heating. First, the tog of the underlay must be below 1.0 in order to ensure enough heat gets through to heat the room.

Although a tog of less than 1.0 is normally sufficient, the lower the tog value of the underlay, the better. For underlays that have been designed for underfloor heating in combination with a carpet, a target tog should be 0.8 or less. For underlays for hard flooring, a tog of less than 0.4 is ideal.

The second consideration is the ability of the underlay to withstand the direct heat from the underfloor heating system. Some can end up drying out or crumbling when exposed to heat, which will ultimately cost more time, money and hassle in the long run. It is therefore crucial to choose the right underlay the first time.

Contract flooring
Durability is clearly a priority for floorcoverings in retail and leisure environments, particularly high traffic areas such retail showrooms, hotel receptions, casinos, corridors and offices.

A key performance enhancer is a good quality underlay, which will protect the floorcovering by absorbing the impact of foot traffic and, in the case of carpet, prevent the pile being crushed and destroyed. This is most easily assessed by looking at the measurements of ‘Work of Compression’ and ‘Compression Under Static Loading’ found on technical specification sheets provided by underlay manufacturers.

Rubber underlays, particularly crumb rubber products which are flat and dense, are good for heavy footfall offering maximum protection and good levels of comfort (and they’re also very good over stair nosings).

The use of a resilient underlay can contribute to not only the tangible performance of a specified floorcovering, but also the installation’s environmental credentials which are becoming increasingly important particularly in the construction industry.

Given the current war on plastic it’s worth mentioning the green credentials of rubber underlays which are 100% recyclable at the end of their life, with many containing not less than 65% recycled content.

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