Flooring is one of the most important aspects of any interior design, and underlay is an essential component to ensure your flooring lasts and performs well. When it comes to installing flooring, many homeowners wonder whether using two or more layers of underlay will provide better results. The short answer is that doubling up on underlay is not recommended and, in fact, can cause more harm than good. But before we dive into why you should avoid multiple layers, let’s explore what an underlay is and the critical role it plays in the flooring installation process.
What Is the Function of an Underlay?
Underlay serves as a protective layer between the subfloor and the flooring material, providing multiple benefits that contribute to the longevity and performance of your floors. Here’s a breakdown of its essential functions:
- Comfort Underfoot:
One of the primary reasons for using an underlay is to create a softer and more comfortable walking surface. When laid under your flooring, it provides a cushion that makes each step gentler, reducing fatigue and improving overall comfort. - Levelling Uneven Surfaces:
Subfloors are rarely perfectly even, and underlay helps to smooth out any imperfections. By covering small lumps, bumps, or cracks in the subfloor, it ensures your flooring material has a stable and uniform base to sit on, preventing future issues like sagging or uneven boards. - Insulation and Energy Efficiency:
Underlay plays a vital role in insulating your floors, helping to keep your home warmer by reducing the transfer of cold air from beneath the floor. This extra insulation can be particularly beneficial in rooms like basements or on ground floors, where cold from the ground can seep in. Additionally, underlay can improve energy efficiency by reducing the amount of heat lost through the floors, thereby lowering energy bills. - Sound Absorption:
If you’ve ever lived in a home with hard flooring, you’ll know how much noise it can create. The clatter of footsteps, the scraping of furniture, and even everyday conversations can echo through the room. Underlay acts as a sound barrier, absorbing noise and reducing sound transmission between rooms or levels in the home. This is especially valuable in multi-storey properties where noise from above can be disturbing. - Moisture Protection:
One of the less obvious but incredibly important roles of an underlay is protecting your floors from moisture. Moisture rising from the subfloor can cause wood flooring to warp or laminate to swell, leading to costly damage. A high-quality underlay will act as a moisture barrier, helping to keep your floors dry and in top condition for longer. - Shock Absorption and Stability:
Underlay doesn’t just make your floors more comfortable—it also helps maintain their structural integrity. Acting as a shock absorber, it protects your flooring from the impacts of heavy furniture or regular foot traffic, which can cause wear and tear over time. It also helps improve the stability of the flooring, particularly for floating floor installations such as laminate and engineered wood flooring, ensuring a secure and snug fit.
In summary, underlay is an essential part of any flooring installation, offering benefits ranging from improved comfort and noise reduction to moisture protection and energy efficiency. But does that mean more underlay is better? Let’s explore why using two or more layers of underlay may not be the best idea.
Should You Use Two Or More Underlays?
It might seem like using two or more layers of underlay would double the benefits, but this is a common misconception. In reality, adding extra underlay can have negative consequences for your flooring. Here’s why:
- Excessive Compression Under Heavy Loads:
Flooring underlay is designed to offer a specific level of cushioning and support. When you add additional layers of underlay, particularly materials like fibreboard, the overall thickness increases. This means that under the weight of heavy furniture, such as sofas or wardrobes, the underlay will compress more than intended. This can create visible gaps between the flooring and the skirting boards as the floor sinks under pressure, detracting from the appearance of the room. - Instability and Floor Damage:
While a single layer of underlay helps stabilise the floor, too much cushioning can have the opposite effect. When multiple layers are used, the flooring material (such as laminate or engineered wood) may not sit securely on the underlay. The excessive movement caused by the extra cushioning can lead to the floorboards bending and dislodging over time, especially in high-traffic areas. This instability can reduce the lifespan of your flooring and result in the need for costly repairs. - Compromising the Locking System:
Many types of modern flooring, such as laminate and engineered wood, rely on a locking system to hold the planks together. These systems are designed to work with a specific level of firmness underfoot. Adding additional layers of underlay can compromise this locking system by creating too much movement and stress on the joints, causing them to come apart. This could void the manufacturer’s warranty, leaving you without protection if something goes wrong. - Difficulty in Securing the Flooring:
Another issue with using multiple layers of underlay is that it can make it harder to secure the flooring onto grippers, especially with floating floors. The additional padding prevents the flooring from getting a firm grip on the subfloor, resulting in an unstable installation that is more prone to shifting and movement. - Impact on Flooring Warranty:
Many flooring manufacturers specifically advise against using more than one layer of underlay, as this can void the product’s warranty. The extra cushioning places unnecessary stress on the locking mechanisms and joints of the floor, making it more likely to fail prematurely. If the warranty is voided, you won’t be able to make a claim if your floor develops issues related to improper installation. - Old Underlay Can Contain Dirt and Dust:
While it might be tempting to leave an old layer of underlay in place and simply add a new one on top, this is not a good idea. Over time, old underlay can accumulate dirt, dust, and other debris, which can affect the hygiene and overall quality of your flooring. When replacing your flooring, it’s always best to remove any old underlay and start fresh with a new single layer.
To summarise, while it might seem like adding an extra layer of underlay would provide additional cushioning or insulation, doing so can lead to a host of issues that can harm both the appearance and lifespan of your flooring. So, what’s the alternative? Instead of doubling up, invest in a high-quality underlay that provides the right balance of comfort, support, and protection.
What is the Alternative?
Rather than using multiple layers of underlay, the best approach is to invest in a high-quality, single underlay that meets all your needs. There are many different types of underlay available, each offering unique benefits depending on the type of flooring you are installing and the specific requirements of your space. For example:
- Foam underlays are great for sound insulation and comfort underfoot.
- Rubber underlays provide excellent durability and resilience, ideal for high-traffic areas.
- Moisture-resistant underlays are essential for rooms with higher humidity levels, such as bathrooms or basements.
By choosing the right underlay for your project, you can achieve the desired results without the risks associated with doubling up. For guidance on selecting the best underlay for your flooring, check out our article on the Best Flooring Underlay, where we discuss the top-rated options available for 2024.
Conclusion
Underlay plays a vital role in protecting and enhancing your flooring, providing benefits such as improved comfort, noise reduction, and moisture protection. However, when it comes to underlayment, more is not always better. Using two or more layers can compromise the stability, performance, and lifespan of your floor, leading to costly repairs and voiding warranties. The best solution is to invest in a high-quality, single layer of underlay tailored to your specific flooring and room requirements.
By following this advice, you can ensure that your flooring remains beautiful and functional for many years to come.
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FAQ
Can you use more than one layer of flooring underlay?
No, using more than one layer of underlay is not recommended. It can cause issues like excessive compression under heavy furniture, leading to gaps between the floor and skirting boards, and may compromise the floor’s stability and lifespan.
What is the primary function of flooring underlay?
Underlay serves several purposes, including providing comfort underfoot, levelling uneven subfloors, offering insulation for heat retention, absorbing sound, and acting as a moisture barrier to protect the flooring from damage.
What happens if you install two layers of underlay?
Adding two layers of underlay can result in floor instability, cause the boards to bend, and weaken the locking system that holds the flooring in place. This instability can lead to damage over time and might void the manufacturer’s warranty.
Does old underlay need to be removed when installing new flooring?
Yes, it’s important to remove old underlay when replacing your flooring. Old underlay may contain dirt and dust and could reduce the new floor’s performance. It’s always best to start with a fresh, single layer of underlay.
What’s the alternative to using multiple underlays?
Instead of using two layers, opt for a high-quality single underlay tailored to your specific needs. Whether you need sound insulation, moisture resistance, or durability, a good underlay will provide all the necessary benefits without the drawbacks of doubling up.
