The Ultimate Guide To Choosing The Perfect Underlay

Just because underlay isn't visible doesn't mean it shouldn't be given careful thought and consideration when installing new flooring either in just one room or throughout your home.

This guide will help you to understand the importance of underlay, the different roles it has and all the key things to think about when you are wondering: 'what underlay should I use?'

As a general rule using the best underlay that you can afford is always a good idea, as good underlay increases the lifespan of your flooring by helping to prevent wear and tear.

We would also recommend that you never re-use old underlay; underlay will hold dirt, bacteria and dust and due to the nature of it will deteriorate and compress over time reducing the comfort underfoot, noise reduction and thermal insulation.

Understanding the Role of Underlay

Underlay has many key benefits whatever the type of flooring you are considering.

A good quality underlay can lengthen the lifespan of your flooring by helping to protect it, acting as a shock absorber especially for luxury vinyl, laminate flooring, solid wood and engineered wood flooring. This is the case for carpet underlay as well as hard flooring.

Underlay also adds to the luxurious feel of your flooring, with wooden flooring and engineered wood flooring it helps to make it feel soft underfoot and is gentler on those who tend to fall a lot; making it great for young families. Carpet underlay can make your carpet pile feel thicker and more luxurious too.

One of the few downsides of wooden flooring especially solid wood flooring is that it can be noisy, especially when used in larger or minimalist homes or rooms where echoing plays a part. Noise is also a consideration in busier homes such as family homes with noisy children and pets. Some people even avoid installing solid wood or engineered wood flooring upstairs in their homes for fear of the noise. However, underlay especially certain types of underlay including sponge rubber underlay, waffle sponge rubber and high density foam can dramatically impact sound.

Factors to Consider When Choosing Underlay

Using the correct underlay for the type of flooring, the home and room requirements, and your individual needs is of paramount importance.

Flooring Type Compatibility

The type of underlay that you will be the best underlay for your home will depend on the flooring type you have chosen.

Some of the best carpet underlay choices include polyurethane also known as PU foam. PU foam is made from recycled furniture foam making it a great environmentally friendly option too. Another great choice for carpet underlay is waffle foam which includes air pockets that help to keep your carpet cleaner.

For very high traffic areas and areas which have heavy furniture then a very durable and hard wearing type of underlay is crumb rubber underlay.

Thickness and Density

The thickness and density of underlay is an important factor when it comes to shock absorption, better insulation and noise reduction. These are also two of the factors considered when underlay is given its tog rating - the thicker the underlay and the more dense the underlay (in combination with the type of structure) the higher the tog rating.

Moisture Resistance

Not all underlay is moisture resistant, sometimes are moisture barrier underneath the underlay is a good idea. However, some of the best underlay options such as Junckers Polyfoam Underlay includes a moisture barrier as well as it foam cell structure.

Sound Insulation

Underlay is key in reducing noise in a home or office this is of especial benefit in a room such as a baby's nursery. Some of the types of underlay we stock at Wooden Floors UK such as New Era Acoustic Underlay not only provide excellent sound reduction but are also can be an eco friendly option as are made from recycles car tyres.

Underfloor Heating Compatibility

If you have underfloor heating systems in place you should still prioritise new underlay. However, for underfloor heating the right underlay for you will be one with a low tog rating, that is one that is not created with heat insulation in mind. Expanded polyethylene and polyfoam are commonly used in combination with underfloor heating and are compatible with carpet, engineered wood, solid wood and laminate flooring.

Types of Underlay Materials

Foam Underlay

Foam underlay comes in various thicknesses and can include a moisture barrier or not. Some foam underlay such as PU foam is made from recycled materials making it a more environmentally friendly underlay choice too.

Foam underlay is a great insulator and is perfect for sound reduction especially for foot traffic.

The huge variety of thicknesses available also mean it is available to suit a variety of budgets; the Junckers SylvaFoam for example is more economical but still provides excellent quality and is one the best underlays for floating solid wood or engineered wood floors.

Rubber Underlay

For floors that undergo more wear than many rubber underlay particularly crumb rubber is an excellent choice. It springs back easily meaning that even heavy furniture will not leave indentation marks. Many of these crumb rubber types of underlay have an integral moisture barrier, provide excellent noise reduction and have a low tog rating making it ideal for underfloor heating. It is also often a great economical and environmentally friendly choice such as the WFUK Floor Layer Pro.

Felt Underlay

Felt underlay can be a popular choice under carpets made of real wool fibres. This is becuase it in theory allows more air to circulate and therefore helps to prevent moisture build up and the mildew associated with that.

Cork Underlay

Cork underlay can be used under carpets, laminate flooring, tiles, wood and engineered wood and can be laid on almost any subfloor. Cork is not moistureproof, but has a certain amount of water resistance and is great for reducing noise. Further to that it is soft underfoot and can be considered to be environmentally friendly as, depending on the processes used to make it, can be biodegradable.

Installation Tips and Best Practices

Preparing the Subfloor

Good quality underlay isn't a substitute for preparation of the subfloor. Remove any old underlay completely. Sweep and/or vaccum the floor and remove any staples, nails or anything else that is causing lumps and bumps.

Proper Underlay Installation Techniques

  • Once you have prepared the subfloor you should remove the doors, this will make laying your floor much easier and prevent problems later.
  • Make sure that you have your underlay the right way up. Check the manufacturers instructions.
  • Lay your underlay over the top of the grippers.
  • Staple the underlay in place; when laying underlay on concrete floors instead of stapling use a spray adhesive.
  • Make sure there are no gaps between the strips of underlay.
  • If you are installing a wooden floor, lay the underlay the opposite way that the planks will lay.


In our opinion, it is well worth taking your time to consider carefully your underlay options, and what will be the best options for you room by room. Underlay is as much an investment as the beautiful floor that sits on it and it will help to protect that floor too so don't be tempted to keep underlay out of sight and out of mind.

We hope this article has helped you to look at underlay in a different light, if you require more information please get in touch with our team at Wooden Floors UK.


Your feelings about the post?