How to lay underlay

How to lay underlay

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Do you want to make your flooring comfortable underfoot and also help save some money on your heating bills? Then you need to consider an underlay underneath your flooring. Available in a variety of thicknesses and materials, underlay is essential for carpet and laminate flooring. We always recommend that you hire a professional fitter to fit your flooring, including underlay, and we have an incredible fitting service that you can take advantage of when you buy flooring from Tapi.

For the keen DIY enthusiasts out there, you may want to fit your underlay and flooring yourself, so we’ve gone through some of the different types of underlay that you may want to fit and gone through the steps of fitting each.

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How to lay carpet underlay

Carpet underlay is used underneath carpets to make them softer and warmer underfoot. They help to give carpets that ‘sinking into’ sensation, and they are made of materials that naturally create barriers of insulation, helping you to keep the heat in and the cold out. Find out more in our guide to underlay, or read on to find out how to fit your underlay. To lay carpet underlay, you’ll need to follow these steps:

  1. Measure your room - As with any flooring fitting, you’ll need to measure your room accurately before you begin to ensure that you get enough materials to cover your entire floor. It’s important to ignore any protrusions in the room, such as a floor sink or fitted cabinets, as you can cut your underlay around these. We’ve got a handy guide on ‘how to measure a room’ you can use for expert guidance.
  2. Prepare your subfloor – whether your subfloor is wood, concrete, or another material, you need to ensure that it is clean and dry before you put anything on top of it. This helps to keep your flooring from getting damp and damaged, and also ensures that your flooring is even too.
  3. Lay your underlay – Ensuring that your underlay is rubber or foam-side down, roll out your underlay across the floor, keeping it as straight and flat as possible so there are no overlaps or bumps.
  4. Stick your underlay to your subfloor – use adhesive glue or staples to make sure that your underlay is firmly attached to your subfloor.
  5. Lay your carpet on top – Now you can have your carpet fitted on top. Remember that caring for your carpet is the most important way to look after your flooring and your underlay.

How to lay laminate flooring underlay

As with carpet underlay, you’ll follow the same process for laying laminate underlay – this is also the same process you would use for luxury vinyl tiles that and engineered wood, both of which tend to be fitted in the same click-profile manner.

Start by cleaning your subfloor and ensuring that it’s completely even. This is even more important for laminate flooring, which clicks together in separate boards, as any bumps or unevenness will result in poorly fitted laminate and potentially bigger issues like laminate floor lifting.

However, underlay does a great job of covering any minor imperfections, which is why it’s so important to include underlay underneath your laminate flooring. it also helps to make your laminate flooring feel more solid and less bouncy. There are different types of underlay you can use for laminate flooring – foam, fibreboard, and foil underlay. 

  • How to lay foam underlay: Polyethene foam underlay is a budget-friendly choice of underlay for laminate flooring and is laid in the same way as carpet underlay, ensuring that all of the rolls of foam line up correctly and don’t overlap.
  • How to lay fibreboard underlay: These boards are made of fibreboard, which is breathable and thin, allowing your laminate flooring to remain dry. It can be laid individually on your floor and stuck down using adhesive or nails – these are one of the easiest laminate underlays to lay down, as they’re so easy to reposition. Just remember to allow your fibreboard underlay time to acclimate to your room - we recommend at least 48 hours.
  • How to lay foil underlay: Foil-backed underlay is one of the best underlays available on the market, with amazing heat retention and damp-resistance properties that will benefit your laminate flooring. Always lay this underlay with the foil side facing downwards and use the overlap guidelines to help ensure you don’t cross the rolls over too much.

Now you can fit your flooring – We have a really handy how to lay laminate guide with steps on fitting your laminate flooring.

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How to lay underlay on stairs

Fitting underlay on stairs can seem like a more daunting task than a square flat room, but it’s a very similar process and can be done with a little extra effort. First things first, you’ll need to take measurements of all the areas that you want to carpet – follow our how to measure stairs and landings guide to make sure you nail it the first time.

Alternatively, if you’re planning on using a stair runner instead of carpeting your entire stairs and landing, then you’ll want to find out a little more about how to do this in our DIY corner. 

How to lay underlay on a concrete subfloor

Concrete subfloors are a little more difficult to lay underlay on top of than wooden subfloors because they’re so strong, so using nails and staples won’t work as well. If you use special concrete nails then you can achieve this, but if you want to find a more cost-effective option, you should opt for concrete glue. This will ensure that you can stick down your underlay in every area, including tight corners or obstructions like a pedestal sink.

It's really important to use an underlay that is moisture-resistant when you’re working with concrete subfloors too because concrete subfloors can release moisture that will damage your laminate boards or carpet.

Don’t want to lay underlay yourself?

Whether you decide that you’d rather have a professional help you out, or if you get part of the way through and need a little assistance, our flooring experts are always on hand to help you out. You can pop down to your local Tapi store, or you can book a free video call to talk through what you need a hand with.


Published: 05-10-2022