Underlay FAQs


Underlay is just as important as the flooring itself. As well as adding extra comfort underfoot, it helps to insulate the room, reduces noise from stompy feet, acts as a shock absorber, and improves the lifespan of the flooring. Thick underlay can also help to smooth out minor imperfections in an uneven subfloor, creating a level surface on which to lay your new flooring. We've answered a few of the most common underlay questions, but if you're not sure which underlay to choose, one of our flooring experts in-store can help.

Do I need underlay?

Whether or not you need underlay depends on the type of flooring. If you're laying down carpet or laminate, you'll definitely need to fit underlay underneath. Vinyl, on the other hand, has a squishy foam or felt backing so it doesn't require underlay, just spray adhesive around the edge of the vinyl for a loose lay, or HT adhesive for a full stick. 

Luxury vinyl doesn't require traditional underlay. With dryback LVT, you can either use HT adhesive or our LVT flexible self-adhesive 'underlay' - a sticky sheet that can be trimmed to size that's so quick and easy to install. Our flexi underlay is also compatible with click LVT; however, all our current ranges of click LVT have underlay already built in - clever!

A member of Team Tapi can help you decide which underlay is best for your new floor, so pop into your nearest store for some expert advice.

How long does underlay last?

Oh, that's a tricky question! Some carpet retailers will claim that underlay can last 25 years, but what exactly does that mean? Like an ageing popstar on a 25-year reunion tour, it certainly won't be performing as well as it used to! There are a number of factors that affect how long underlay lasts. Thicker underlay will last better than thinner underlay as it will take longer to flatten down. Underlay will wear down quicker in rooms where there's a higher footfall. Moisture and heat will also have an impact on the life of your underlay. Underlay made from synthetic materials will disintegrate slower than ones made from natural materials. If your flooring is looking a bit tired, chances are the underlay below is the same, so we'd strongly recommend replacing your old underlay whenever you get new flooring.

Can I reuse my old underlay?

Most of the time, you shouldn't reuse old underlay. We recommend that you buy and fit new underlay at the same time as your new flooring. Old underlay can disintegrate as it ages, as well as harbour lots of dust and dirt. It will have compressed over time where you've walked, so reusing old underlay will affect the performance of the new flooring laid on top. Your underlay might look in reasonable condition if you lift up the edge of your flooring to check it, but remember that’s an area where there's been no footfall! At Tapi, we can come and have a look at your existing underlay when we measure up to assess whether new underlay is required. If it’s relatively new (laid in the last couple of years) then it should be ok to reuse.

What's the best thickness underlay?

The thicker the underlay, the more cushioned your floor will feel underfoot. Choosing a thicker underlay helps to dampen sound better, increase thermal insulation, lengthen the lifespan of the flooring itself, and level out any imperfections in the subfloor. Our underlay for carpets ranges from 8mm to 11mm, whilst laminate is 1.8mm thick and LVT underlay is 3mm. But remember, if you've got underfloor heating, the thickness of the underlay can have an impact on how much heat flows into the room.

What underlay should I use for carpet?

Carpet underlay comes in a variety of different materials, including recycled PU foam, sponge rubber, and even old car tyres! The thickness of carpet underlay ranges from 8mm - 11mm, with the thicker styles being a better option for rooms with heavy foot traffic. Take a look at our range of underlay or speak to one of our flooring experts in-store who can help you decide which underlay is best for your carpet.

Will carpet underlay work for laminate flooring?

You need to choose underlay that's compatible with your flooring type. Carpet underlay won't work with laminate flooring. If you're changing from carpet to laminate then you'll have to change your underlay to one that's suitable for laminate flooring. Carpet underlay is thicker and more cushioned, and putting laminate flooring on top will put pressure on the joins where the planks lock together.

What underlay should I use for laminate?

Our laminate underlay is only 3mm thick but it can make a huge difference to the performance of your floor! Made from PE foam, it's specifically designed to increase airflow under your laminate flooring to reduce the build up of moisture, but will also help to reduce the noise from stompy feet for a more peaceful home. We also offer another laminate underlay with reflective backing, which is the best option if you've got underfloor heating.

Which underlay is best for LVT flooring?

Whilst you don't need traditional underlay for dryback LVT flooring, you will need something to stick it to the floor! At only 1.8mm thick, our LVT flexible 'underlay' is designed for the installation of dryback LVT without the need for adhesives. It comes with a self-adhesive side for a quick, clean and simple installation.

Click LVT, on the other hand, does require underlay and Tapi's flexi underlay is also compatible with click LVT. However, all our current ranges of click luxury vinyl flooring feature a built-in rubber underlay, which gives each plank a strong core for extra support underfoot and reduces the sound and impact of footsteps.

Do I need underlay for stairs?

Yes, you do! Foot traffic is high on stairs so underlay is essential. Technically, it's only needed on the tread of the step (the flat part), but most fitters will put underlay on the riser as well. The fitter will cut the underlay into sections to fit each step and then lay the carpet over it. This will all be included when we calculate the total amount of underlay you need.

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