Thick underlay may be the gold standard, but those measuring 10-11mm are a great compromise. They're thick enough to provide an excellent level of comfort and warmth, and capable of withstanding high levels of foot traffic. Yet 'thin' enough that it's easy to handle and install the underlay – even for a DIY novice!
Underlay thickness affects the feel of the carpet. A thick underlay, between 11 and 12mm, will give your carpet a cushioned, soft feel. However, a thinner underlay on the stairs may be easier to install. 9mm is ideal.
Another consideration is the thickness to choose, foam underlay being generally available in 7mm up to 12mm thicknesses. A 7mm standard quality foam underlay would be considered a budget price option, whereas a high density 8mm to 12mm would be regarded as a good option to give great support to your new carpet.
Underlay for laminate flooring is usually 3 mm thick. This may seem thin, but using thick underlay will create too much bounce when people walk on it and cause the floor to move underfoot.
We would recommend an underlay of 3 – 5mm for laminate flooring. It should be at least 3mm thick to provide comfort and ground levelling properties. But, it should be no more than 5mm thick.
Extra Padding Poses a Risk
By adding unnecessary cushioning, you could actually be causing more harm to your floor than good. The added friction could cause the underlayment to wear down quickly and make your floors less stable over time, causing stress on the floating floor's locking system joints.
Fibreboard underlay
Not to mention, it's also the number one choice of underlay for laminate and wooden floors. If you have an uneven subfloor, the fibreboard will help even any dips and dents you can't level out.
Good underlay can improve everything from how flooring feels underfoot, to how it wears and maintains its looks over time. In fact, investing in your underlay can increase the lifespan of your flooring by 30-50%. Of course, there are other benefits too.
We'd like to get one thing clear from the start – underlay thickness does matter. Getting it right can make a huge difference to the final look and feel of your new flooring, having a significant impact on its underfoot comfort, sound and heat insulation, and longevity.
The thicker the underlay is, and the higher its TOG rating, the more thermal insulation it'll provide. Which is why, our recommendation is Royale® 7mm Professional Sonic Gold. This is regarded as the best underlay for laminate currently on the market.
More than 70% of consumers say that comfort is important to them when it comes to selecting one. Comfort depends on the underlay's density, material, thickness, and tog rating as well as the types of carpets in your home. A thick PU foam underlay like Tredaire Dreamwalk gives a luxurious feel underfoot.
This is because the underlay will simply follow the shape of the subfloor which is not flat. Furthermore, laying more than one underlay will reduce the stability of the subfloor and cause more issues than they fix. Ultimately, levelling a subfloor with underlay will do nothing but cost you an extra few dollars.
Two major factors though, will help you to decide which one is ideal for you. The two most important factors you need to consider when choosing an underlay for laminate flooring, is the type of sub-floor you have in the room, on which the floor will be fitted and the kind of insulation you want to provide to it.
Fibreboard Underlay
This is the best choice for both types of flooring. It works to smooth uneven floors, reduces noise, and acts as a thermal barrier. If the subfloor is uneven, fibreboard works to even dips and dents you can't level out.
A good-quality underlay has a number of benefits for your floors. They include: It makes the carpet feel softer. This is because it is usually made of a softer material such as felt.
The Importance of Underlay
Not too thin and not too high. But most critically, it's the weight or density of the underlay that indicates it's quality. 90kg is a good average grade and 110 to 120kg (more foam that air) is a good quality underlay.
To avoid buckling, subfloor panels should be spaced with a 1/8-inch gap at all edges and ends to provide room for naturally occurring expansion. Tongue-and-groove edges on many premium floor panels, such as Weyerhaeuser's Edge Gold® OSB panels, are designed to self-gap.
When installed with staples, the underlayment sheets are fastened every 2 inches along the edges of the sheet and every 4 inches in the field area. Screws and nails may be spaced farther apart. Sheets can be butted together (just touching, not forced tightly together) or they can be gapped about 1/8 inch, or so.
The best materials for floor underlayments include foam, cork, and polyethylene (thermoplastic). If you're looking to add softness while absorbing sound and preventing mold and mildew, cork might be your best bet. 4 If your main goal is to add a moisture barrier, polyethylene might be a better choice.
There is such a thing as too much cushioning. A thick underlayment with low density will compress when weight is put on the flooring system, causing the flooring planks to bend and ultimately damage the locking mechanism.
Yes, most underlays are technically supposed to last for a couple of decades or more. But it's worth keeping in mind, no matter how expensive or luxurious your new floor covering may be, its final look and feel will only ever be as good as the underlay underneath.
Foam Underlay
This is mainly because it offers more comfort, and can make your carpet feel even better. It's also made purely from recycled materials and old scraps of foam, making it a more environmentally friendly option.
Laminate flooring is very thin, so any unevenness on the subfloor will eventually begin to show as the floor settles into position – you can find out more about this in our 'What is laminate flooring' guide. The spongy effect can be caused by a dip in the subfloor causing an air gap underneath the laminate flooring.
Thickness
If there are minor imperfections in your subflooring, you'll want a thicker pad to cover those up and smooth the new surface out. If you don't have a lot of space to add new flooring, a thinner pad will likely be a better choice.
Without underlayment to add a layer between these damp subfloors and the surface flooring, your laminate can quickly become wet, warped, and mildewy, harming its overall integrity. Moisture over time can also break down floor adhesive which causes the floor to start warping.