Decoding Floor Layers: The Difference Between Floor Covering, Underlayment, Subfloor, and Joists?

Whether you are laying down a nice, cozy carpet or an elegant, herringbone parquet wood, a lot is going on underneath that surface. Your flooring plays a huge role as it bears everything in your home. In fact, it is the only place in your house that supports everything, whether it be your weight, various pieces of furniture, machines, and more. Not to mention that it is also one of the major deciding factors in providing a decorative look to your house. A general floor typically has four layers: floor covering, underlayment, subfloor, and joists. The first layer called floor covering is something that most homeowners are aware of. It is normally what they look for when they’re dealing with a Maryland flooring company or any local contractor. But beneath that floor covering are the subfloors, underlayment, and joists that most homeowners hardly ever know of. 


So, in this guide, we will identify each one of them—each layer that, if combined and installed properly, can build up a smooth, strong flooring that you have now. 


Floor Covering 

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Floor covering is the topmost layer of your floor. It is the visible floor, or a general material installed over the subfloor for a good-looking surface or finish walking. This is the layer that you can typically change out. Floor covering gives supplementary support but is not required to provide structural support. It might be your ceramic tile, carpet flooring, luxury vinyl, or solid hardwood. The right type of floor covering for your home is highly subjective, so you need to discuss your options with a Maryland flooring company for specifications and recommendations.



The first layer below the floor covering is the underlayment. It is an intermediary layer that is not compulsory for each floor installation but is recommended most of the time. The placement of underlayment between the top floor covering and subfloor provides a smooth, consistent base for the floor covering. 

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While this material is an optional layer, any Maryland flooring company or contractor may recommend installing the underlayment in floor construction because of its myriad benefits. The material hides the bare floor from any harsh elements of the external environment. Not only does it provide a smooth surface, but it also improves the adhesive nature of the bare floor, especially in the case of tile flooring. Underlayment has moisture resistance, so it can prevent any moisture to rise from the foundation up through the floor covering. Also, it is a good insulator, keeping your floor warm and noise-free at the same time.


Types of Underlayment

There are three types of underlayment: standard foam, upgraded foam, and combo underlayment. Let’s discuss each type. 


Standard Foam Underlayment. As the name implies, it is a thin, simple layer of foam on top of the subfloor. In most cases, it partners with a moisture barrier to avoid any moisture passing through the floor and the entire room. 


Upgraded Foam. A better version of the standard foam, it acts as a noise-absorbing material inside your home. Not only it conceals the bare floor, but it also lasts longer than the standard foam underlayment. 


Combo Underlayment. This underlayment is a combination of film and foam. It provides comfort on your feet and serves as an absorbent material to suppress liquid or moisture to pass through the floor. Typically, combo underlayment is laid over plywood or a concrete subfloor. 



The subfloor is the second layer below the floor covering and the hardest amongst floor layers. This flat surface below the underlayment and above the joist is a piece of material that holds up all of the above floor layers, including everything in your home such as furniture, people, pets, to name a few. Since it handles a whole lot of weight in your house, a subfloor is mandatory for every home. Your Maryland flooring company or contractor should build a strong base or subfloor to support the entire house and stabilize the foundation. The subfloor is durable and rigid enough to withstand the worst conditions on your flooring and your house in general. 

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Types of Subfloor 

In today’s flooring market, we can typically find these subfloor types: pine, plywood, particleboard, flakeboard, and concrete. 


Pine. This subfloor is from pine wood—a soft and malleable type of wood. Primarily used in apartments, homes, and residential buildings, pine can be easily shaped to your desired outlook. 


Plywood. Produced by laying multiple sheets of wood, plywood is a durable material. Because of its evenness, strength, and flatness, plywood is the most common form of subfloor in the market today. This material comes in thinner and thicker versions and is easy to install. The thinner form is effective for vinyl flooring, while the thicker version is good for tile flooring. 

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Particleboard. Made from finer wood particles, sawmill shavings, and wood chips, particleboard or chipboard is a compact subfloor material that can resist moisture to pass through the floor. 


Flakeboard. This type of subfloor is manufactured from flakes of wood that are flattened, then glued together with a synthetic resin. It is less compact than particleboard and more susceptible to moisture or water. Hence, it is not ideal in moisture-prone areas. 


Concrete. For the basement and ground floor, it is ideal to choose a concrete subfloor. It is easy to fix, especially on tile flooring. However, it can release moisture to the floor covering, so your Maryland flooring company might recommend having an underlayment on top of it. 



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Though the joist is not really a floor layer, it is an essential component of the entire flooring construction. With the exception of concrete flooring, joists are structural and fundamental parts of any flooring architecture. It is placed between the beam to create a sturdy support for the subfloor. This bottom-most layer of flooring architecture can be made of laminated wood, dimensional lumber, steel, or engineered wood. The quality and durability of the joist material will determine the weight-bearing ability of your floor. The closer the joists are, the more load it can bear. In this case, you may need your Maryland flooring company or builder to assess the type of joist material needed for the flooring construction. 


Ready to Start Your Flooring Makeover?

Before laying down a new floor, it is important to know if the layers underneath the floor covering are up for the job. A thorough assessment of your subfloor, joists, and underlayment is necessary to determine which flooring materials are ideal for your home. However, if you still need help in your next flooring project, Carpet Ready is here for you. Contact us today so we can provide you a free in-home consultation!