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How To Fit Underlay

Originally posted 29th July 2016. Last updated 23rd January 2020.

Post Authors
Paul Hambidge

Managing Director Factory Direct Flooring Ltd

Once you've decided on the perfect flooring solution for your home it's time for the installation and we know that wanting to avoid making any mistakes with the fitting is your top priority. For that reason we've taken a look at the steps you should take to ensure your floor is perfectly placed, beginning with the base layer of how to fit underlay.

Why you should use underlay

Underlay is the first point of contact your new floor should have. Placing flooring onto the sub-floor of your home, whether this is a concrete, vinyl or asphalt surface, will only shorten the life of the flooring. Underlay provides a protective layer which prevents excessive moisture penetrating the floorboards. It also makes the floor more comfortable to walk on, as underlay is cushioned and made up of several layers of padding. Finally, it will make the room it's in warmer, as the underlay acts as a form of insulation underfoot. To find out which is best for you, view our underlay range.

image of socked feet on wood floor


Read more: Why You Don't Need Underlay For Vinyl

The different types of underlay

Underlay comes in several different forms to suit the flooring that is being placed both on and under. Of these types, wood fibre is the thickest you can use and is the one that should be used if your base floor is a bit uneven. They also give good heat and sound insulation though are not particularly suitable for wet environments such as the bathroom and kitchen.

Image of sweeping a floor

Poly fibre is the thinnest underlay available to put under laminate flooring or other similar forms of flooring. It's suitable for any firm, dry and level sub-floor, such as wooden floors. Before laying underlay make sure the sub-floor is dry, clean and smooth to allow for a perfect finish. Also, never use carpet underlay under laminate or wood flooring as it is completely unsuitable for the job.

How to fit underlay

If you have a concrete, asphalt or vinyl sub-floor you should make sure to cover it first with a damp-proof membrane before you fit underlay. This will prevent moisture seeping through to your underlay and, in turn, through to your flooring. If your sub-floor is concrete lay your underlay with the vapour barrier side down. Tape the seams of the underlay on the top side with vapour tape. On wooden and other types of floor, lay the underlay with the rubber side down.

Image of trying to fit underlay

When fitting underlay, make sure to measure how much you need. You should make sure the underlay extends up the wall by at least 5cm to give yourself some leeway. When it comes to pipes, which are always tricky, make sure to leave a 5-10mm gap around the width of the pipe. . Once you've cut your underlay to size it should be easy to install. Simply make sure you don't overlap the different pieces so that your floor stays smooth and even.

Our Flooring Calculator

When you browse any type of flooring at Factory Direct Flooring Ltd, each product has a flooring calculator on the page. Simply enter the surface area in either metres or feet squared and our My Project flooring calculator will tell you how many packs you’ll need and how much it will cost you.

By simply measuring your room and entering your dimensions, we will provide you with an instant price which will show on every type of flooring you browse across our website. You can either input the total coverage or your width and length measurements, in meters or feet. You can even save your measurements room by room to make your shopping experience stress-free.

It also offers to add an extra 10% for wastage. While this may cost a little bit more, we highly recommend adding it just in case there are mishaps during the installation process. Enjoy the My Project flooring calculator below:

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If you need more advice on how to go about underlay installation then simply call 0300 100 00 15 to speak to one of our flooring experts, who will be more than happy to help you.

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