How to Select the Right Type of Subfloor Material

One must not confuse the subfloor with the underlayment, which is utilized as the base for the completed flooring. The subfloor is an integral part of any floor construction. It serves as a continuous structural level, covering either joists or a cement slab, thereby furnishing the essential base to the finished floor. Wood-frame flooring is fitted over an unbroken subfloor that covers the floor joists. In homes built on a slab-on-grade foundation, the subfloor is often simply the concrete slab.

No matter what type of subfloor material you choose, it is important to ensure that it is properly installed and sealed to prevent moisture from seeping through and damaging the finished flooring.

Common Types of Subfloors

When it comes to choosing a subfloor material, there are a variety of options to consider. Different materials should be chosen according to the type of environment in which they will be installed. Wooden flooring is a timeless material known for its resistance and versatility, with hardwood and engineered wood being the two main flooring types. Floors systems typically consist of four layers: joists, subfloor, underlayment, and floor finishing. The subfloor is the layer that provides sound support and insulation over the joists and under the finishing.

Types of Subfloor


Plywood is a type of manufactured wood made by gluing layers of veneer together. It has been a common subfloor material since the 1950s and is of higher quality than oriented strand board, making it able to withstand more pressure over time. However, standard plywood can separate when exposed to extreme heat, so it may not be suitable for warmer areas. For best results, 3/4-inch tongue-and-groove plywood subflooring should be used and glued and screwed or nailed to the floor joists.

When installing plywood as a standard subfloor, it is important to take the necessary steps to ensure that it will last for years to come. Plywood should be installed correctly with all joints glued and screwed or nailed into place. This will help prevent any warping or separation due to extreme temperatures or moisture levels in the air.

Concrete Slab

Concrete slabs are an important part of many flooring installations. They are typically 4-6 inches thick and have a strength rating of 3,500-5,500 psi. It is important to test the slab for moisture before installing finished floors as this can affect the performance of the flooring. Concrete subfloors are generally compatible with wood floors at or above grade, but engineered bamboo floors are more suitable for below-grade installations due to their moisture resistance and dimensional stability. Glue-down flooring can also be installed on concrete subfloors, provided that the subfloor is tested for moisture beforehand. Floated floors can also be used on concrete subfloors if they are properly levelled out. Concrete provides a hard, durable, steady and often smooth surface which makes it ideal for many types of flooring installations. However, a moisture barrier should always be used when installing concrete in moisture-prone areas such as basements and solid hardwood floorings should not be used in these areas.

Particle board

Particle board is a type of manufactured wood made from wood chips, sawdust, and other wood particles that are bonded together with resin. It is an economical choice for subflooring and can be easily cut into different shapes and sizes to fit any space. Particle board provides good insulation against moisture and temperature changes, but it is not as strong or durable as plywood or concrete slabs. Additionally, particle boards can be prone to warping and cracking over time, so it is important to use a vapour barrier when installing them in areas with high humidity. Particle boards should also be installed correctly with all joints glued and screwed or nailed into place.

OSB (Oriented strand board)

OSB (oriented strand board) is a type of plywood that has become increasingly popular in recent years. It is made by layering 3- to 4-inch wood strands in a crossing pattern and then gluing and pressing them together. OSB boards have a flat and smooth surface, unlike some plywood which can have bumps. This makes it ideal for use as a subfloor, as it provides an even base for flooring materials such as bamboo or engineered wood.

When installing floors over OSB, it is best to consider the floor’s thickness. For solid bamboo floors that measure ¾ inch thick, it can be placed directly on top of a corresponding ¾-inch thick OSB subfloor with planks set at 90-degree angles across the joists. With thinner engineered, cork-backed, solid, or floating floors that are 1/2 inch or less in thickness, it is recommended to add an additional 3/8 – 1/2 inch plywood underlayment on top of the OSB subfloor. This will provide extra stability and support for the thinner flooring materials.

Best Type of Subfloor

Wooden Plank Subfloor

Wooden planks have been used as subflooring materials for centuries and were the traditional choice up until the mid-twentieth century. Most planks are crafted using wood like pine and they measure 1×6 inch size. In many older homes, subfloors are still made of this type of material; however, its tendency to warp over time has made it outdated compared to newer options. When remodeling, wooden plank subfloors are usually put in first and then topped with particleboard or hardboard underlayment before adding vinyl flooring or carpet for a smoother finish.

Wooden plank subfloors are relatively easy to install and maintain, making them a popular choice for DIY projects. They provide a sturdy base for flooring and can be easily replaced if needed. However, they do require regular maintenance such as sanding and sealing to prevent warping and cracking over time. Additionally, they may need additional support when installing heavier flooring materials such as tile or stone. Despite these drawbacks, wooden plank subfloors are still a viable option for many flooring projects.

Best Subflooring Material for Finished Floors

When it comes to choosing the best subflooring material for finished floors, there are several options to consider. The tile should be installed on a concrete subfloor to avoid flexings which can lead to cracks. Hardwood should be installed on a plywood subfloor for easier installation and compatibility. Laminate should also be installed on a plywood subfloor with a thin plywood underlayment to protect it from dents and ridges. Original hardwood floorboards can also be used as a subfloor, with an underlayment layer of plywood added above them if necessary. This is a viable option in old houses where the original wood floors cannot be refinished.

Subfloor Installation Management Tips

Subfloor installation is an important part of any renovation project. It is essential to ensure that the subfloor is properly installed and managed in order to achieve a successful outcome. There are several tips to consider when installing a subfloor, such as measuring moisture levels in the subfloor and comparing them to the manufacturer’s guidelines for acceptable percentage differences. Additionally, it is important to install a vapour retarder over the subfloor to minimize moisture transfer and seasonal humidity fluctuations.

When selecting materials for a subfloor installation project, there are many options available. Consulting an expert can be beneficial when deciding which material will best suit your needs. An expert can provide advice on the best materials and installation techniques for your particular situation. Additionally, they can help you identify potential problems before they arise and offer solutions that will ensure a successful outcome for your project. Taking the time to properly install and manage your subfloor will ensure that your finished floor looks great for years to come.


Two common materials used to construct a subfloor are plywood and concrete slabs. Plywood is an economical choice that can be easily cut into different shapes and sizes to fit any space. It also provides good insulation against moisture and temperature changes. Concrete slabs are more durable than plywood but require more effort when installed due to their weight. They provide excellent soundproofing qualities as well as protection from fire, water damage, pests, and mould.

Other materials used for subfloors include particle board, oriented strand board (OSB), and cement board. Particle board is a cheaper option than plywood but still provides good support for finished floors. OSB is another popular choice due to its strength and affordability. A cement board is a great choice for bathrooms and other wet areas due to its waterproof qualities.

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