Underlayment is an element to consider during the flooring process. You need to subfloor imperfections to get the final floor covering, also known as the finish floor, looking its best. Underlayment also acts as a moisture barrier, reduces flooring sound and provides other benefits depending on the type of finish floor.
Here’s a comprehensive guide to underlayments. The different types, purposes and the results you can achieve with them will all be covered. Whether you hire a professional or you do your flooring yourself, this guide will help you make the right choice.
What is Flooring Underlayment?
Flooring has many layers. Underlayment is a thin, hard/soft layer of material upon which the finish floor rests. Beneath the underlayment is the subfloor. There can also be an extra layer of moisture barrier if the underlayment doesn’t have it built-in. For a clearer idea, typical floor is comprised of the following:
- Top Layer – This is the final floor covering or the finish floor that is visible and on which you walk on. It can be made of hardwood, laminate, tile, bamboo, cork, vinyl or many other materials. The top layer provides minimal protection to the substrate, that is, the layers beneath. The top layer is all about the aesthetics.
- Second layer – This is the underlayment. The material depends its made from depends on your top layer. The main purpose of the underlayment is to provide a smooth surface for the floor covering. It helps the top layer to achieve a consistent look and feel. It also serves other purposes like reducing floor sound and protecting the floor covering from moisture.
- Third Layer – This is the subfloor, a flat surface on which all the other floor layers rest. It’s the main floor structure or the “real floor” that holds up all the other layers and the weight of everything in your house like the furniture, people, and pets. Typically, subfloors are made of concrete, plywood or OSB (oriented strand board).
- Bottom Layer – This is known as Joists, which is an essential part of the entire flooring structure anatomy. It’s the timber or steel part of the structure of the building that is arranged horizontally to support the floor.
Types of Underlayment for Different Types of Flooring
The underlayment requirement for each type of flooring is different.
- For Tile Flooring – Tile floors are popular for wet areas like bathrooms, kitchens and entryways. The underlayment, in this case, needs to be tough to provide support and prevent cracks. It must also be flexible to absorb the expansion and contraction of the tiles resulting from temperature and humidity. Cement board underlayment (CBU) and uncoupling membrane underlayment are the two types of underlayment that are perfect for reducing the stress built up between the substrate and the tile.
- For Laminate Flooring – Laminate floors are a cost-effective alternative to hardwood for many people. Although high-quality laminate flooring already has underlayment in its construction, you’ll need to choose an underlayment if your product doesn’t include it. Foam laminate underlayment and acoustical laminate underlayment are the two options available for laminate floors. Foam is the most basic type of underlayment used. It includes rubber or fibres that provide stability, durability and reduce noise. Acoustical underlayment comes in cork and felt varieties and is highly capable of reducing hollow noises that come with foot traffic.
- For Hardwood Flooring – Hardwood flooring can be made from solid hardwood like oak, maple, hickory, teak and engineered hardwood. Underlayment options for hardwood, bamboo and cork flooring are the same. Felt is the most common type of underlayment material used for hardwood flooring. It’s dense and usually manufactured in rolls. Felt provides decent resistance to moisture, although felt hardwood flooring underlayment may require an additional layer of moisture barrier in very humid areas. Other popular underlayment materials for hardwood are cork and rubber. However, the best underlayment for engineered hardwood is foam as it absorbs sound, resists mold and can also be recycled.
- For Vinyl Flooring – Plywood is the perfered underlayment for vinyl flooring. However, if the subfloor is in excellent condition, you may not need to install an underlayment at all.
Homeowners often ignore underlayment when renovating floors. Flooring done with the proper type of underlayment will give your project better results in terms of appearance and stability. In the next post, we will discuss how flooring underlayment can act as a sound and moisture barrier.