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How Thick Should Subfloor Be? (Read This First!)

Doing extensive remodeling or making a house for the first time, is the first question that comes to mind. You can easily get confused by all the varying opinions on how thick the subfloor should be. 

While the homeowners have their reasons, the truth depends on a number of factors.

How thick should the subfloor be?

The thickness depends on the material of subflooring. The types of subflooring are wood plank flooring, plywood subflooring, oriented strand board subflooring, and concrete subflooring. The minimum thickness for plywood subflooring is 5/8″, and the Oriented Strand Board subflooring is 23/32″.

In addition to the material of subflooring, the distance of joists also plays a significant role in determining the thickness of subflooring. The shorter the length, the less thick subflooring you need.

Here are some subfloor measurements according to the floor types.

For ceramic tile:

The average thickness should be around ½ inch to ¾ inch. The combined thickness of the floor and subfloor should be about 1 to 1/8 inches.

The ceramic tiles are generally very hard and robust. An excellent and enduring subfloor can be built with ceramic tiles. For the ceramic tiles, the floor below should be built with concrete or enough rigid materials to support the heavy tiles.

The ceramic tiles are fastened on the floor using the mortar bed. This mortar bed connects the tiles to the floor. There are different types of underlayment for ceramic tiles.

These are cement board, fiber cement board, plywood, mortar bed. Though the ceramic tiles are very rigid and heavy, the flooring with these tiles might be considered sensitive.

For porcelain tile:

Porcelain tiles are generally hefty, so the floor underlay should be solid. The joist should be very hard and rigid to support the tiles. The minimum thickness should be 5/8 inches with an average of 11/8 inches.

Porcelain is a durable, harder, and even more water-resistant form of ceramic tile than most other ceramic.

Porcelain tile is made by using finer-grained clays baked at a higher temperature, resulting in a harder, less porous surface than regular ceramic tiles. Ceramic tiles’ intrinsic adaptability allows them to provide the best subflooring.

For hardwood:

The most suitable hardwood material for the subfloor is plywood. The plywood is fitted to the joist using nails being screwed and glued.

The plywood subflooring thickness should be around 1/2 inches and 5/ 8 inches. If the hardwood is thicker, it is easier to nail on the joist. Tongue and groove plywood easily fits 8 inches in the floor and helps to avoid frictional sound between the plywood.

For laminate floor:

Plywood subflooring with a thickness ranging from 5/8 inch to ¾ inch can be chosen for laminate flooring.

Laminate flooring is made with such hardwood that it can easily fit in the joist, and there is less chance of hampering the joist. These subfloors are also very suitable for the playing of the kids and pets.

For vinyl plank flooring:

Vinyl Plank Flooring has been a very popular subflooring way, and they have always been less expensive than other options.

The minimum thickness of subflooring for vinyl plank flooring should be ¼ inch. You can use ½ inch subflooring for added support.

Unlike a thin layer of highly flexible vinyl, the Vinyl plank is a considerably thicker flooring material created in long planks with a modified tongue-and-groove connection mechanism.

For ditra:

For ditra flooring, opinions regarding the thickness of subflooring vary. While some suggest a thickness of 3/8 is appropriate, it is always better to adopt a minimum of 5/8 inches.

How thick is the subfloor in a mobile home?

Mobile homes are homes built for any special reason for a particular period of time. Sub-flooring is often needed in the mobile home. The subfloor in a mobile home is mainly 3/4 inches or 5/8 inches thick.

The subfloors of mobile homes are made of particle boards. These particle boards are made of sawdust and glue. Moreover, plywood and oriented strand boards are now used for the mobile home.

How thick should the subfloor be for radiant heat?

Generally, the average subfloor thickness for radiant heat is 1/ 2 inches to 5/ 8 inches. Radiant heat is affected by the object’s temperature. The hotter a thing is, the more heat it generates.

The quantity of heat transferred from a conditioned room to an unconditioned space is known as heat loss. As a result, the thickness of the floor is not a significant factor in heat loss. The floor will radiate heat once it reaches a temperature higher than room temperature.

How thick should a bathroom subfloor be?

The subfloor under the tile of a bathroom should be at least 11/8 inches thick. Most of the time, plywood is used for the subflooring of the bathroom. For your bathroom makeover, the subfloor material should be a top priority.

It’s crucial because the subfloor in a bathroom must be able to survive the high moisture levels, and not all materials are capable of doing so. It keeps water out of places like the sink, toilet, and bathtub that are more likely to flood.

Excess moisture in the subfloor is a major cause of early bathroom flooring damage. Pick the suitable material from the start to save yourself from all the hassle of changing subflooring.

How thick are Dricore and OSB subfloors?

The thickness for the subfloor of Dricore and OSB are at least 3/ 4 inches and 23/ 32 inches, respectively. Dricore floor is much insulated. The OSB subfloor acts as a basis for the finish floor (hardwood, plywood, vinyl tile, etc.) and even the underlayment.

The surface of the OSB is always clean and level. OSB is a good soundproofing essence because of its density. OSB is a more consistent product than other forms of subflooring material since each sheet is equal.

What thickness plywood is used for the subfloor?

The thickness for the plywood subflooring should be at least 5/8 inches. Thicker subflooring is suggested for nail-down the plywood. The plywood panels are glued to the floor joists with construction for a quality installation of the plywood subfloor.

The panels are also attached to the joists by subflooring nails being screwed to them. On the other hand, subflooring with thinner subflooring is suitable for the carpet.

How many layers of plywood do you need for a subfloor?

One layer of plywood is generally needed for the floor of your subfloor. But two layers of plywood can also be made. The one-layer plywood is commonly used all over because of ease. The common thickness of one layer is ¾ inches.

Adding an extra layer is complicated and costly. But it is possible to use two-layered plywoods if necessary.

How to increase subfloor thickness?

After changing tiles or finished flooring in one space, we often see that the height does not match up with other rooms. You do not want to change the flooring, but the height difference is bothering you.

So, you adopt for increasing the subfloor height. The materials needed are a measuring tape, a circular saw, construction adhesive, caulking machine, hammer, screw nails.

 Here is a step-by-step guide on how you can raise the subfloor.

Cutting plywood to the desired size:

The plywood size should be measured, and it has to be set on the floor perfectly. And the plywood should be left in a room where it will cope with the surrounding weather and humidity.

The floor should be cleaned. Carefully cut the plywood adhesive tube at 45 degrees. The adhesive should be carefully loaded into a caulking machine to avoid getting messy.

Fitting the plywood on the subfloor:

The plywood should be installed and fastened to the present subfloor. Install in such a way that the flat surface is faced up. Hammer 1 1/4-inch screw nails from one edge to the opposite. Hammer the screw nails every 6 inches.


The remaining subfloor should be laid using the method mentioned above. Apply glue under the plywood. After gluing, hammer the plywood with screw nails 6 inches apart. Rest the subflooring for a whole day before the final flooring is mounted over it. 

Final Thought:

A subfloor gives a home the proper structure required for strength and enhances the lifespan of a floor. It protects the floor from being damaged. Subflooring can be done with different materials and based on it, the thickness also varies. A subfloor provides rigidity and durability to the home.