What Size Plywood For A Mobile Home Floor?

If you notice that the flooring of your mobile home has become bumpy, uneven, or generally unstable, maybe it's time to replace the structure. What is the best material to use? Is plywood a good option? What size? Read on and find out what our research revealed about your concern.

The recommended material for mobile homes is 5/8-inch thick plywood. It provides a stronger foundation when installed over the existing subfloor, which is traditionally made of particleboard. Plywood would provide a more durable base for hardwood, carpet, tiles, vinyl, or a laminate finish.

Mobile homes are designed and structured differently from traditional houses and buildings. The limited space warrants lighter materials to facilitate transporting considerations. Because of this, most subfloors are constructed with particle boards which tend to weaken and deteriorate easily over time. So why is a 5/8-inch plywood ideal for replacing the material? Read on to learn more.

set of plywood, industrial illustration, What Size Plywood For A Mobile Home Floor?

What Is The Purpose Of Plywood In A Mobile Home Floor?

Holiday, modern mobile home

Mobile homes feature a foundation layer beneath the visible surface finish of their flooring. It is traditionally made of particle boards and is referred to as subflooring.

The material is made of compressed wood chips and resin to create panels for construction. However, it is not resistant to moisture and can swell and expand when exposed to water. Due to this, most mobile homeowners have to replace the layer periodically.

Plywood would strengthen the foundation and structural reinforcement for mobile home floors.

It is actually the most preferred subflooring material in traditional construction because the multiple layers provide durability and stability. Once installed properly, it could serve as the flooring surface itself or overlaid by hardwood, carpet, vinyl or tiles.

Is Plywood The Best Material?

Plywood for construction.

Plywood may not be as durable as certain hardwoods, but for this particular purpose, it may be deemed the best option. It is the most widely used wood-based panel product due to its versatility, strength, lightweight feature, and workability.

Plywood is engineered with several layers of alternating grains running at right angles, referred to as cross-graining.

This configuration strengthens the board in all directions and eliminates weak structures common in ordinary wood. It prevents expansion and shrinkage and is more resistant to moisture and humidity.

The laminated and alternating matrix of plywood distributes the load over a larger area which renders it as an excellent flooring material. The surface remains relatively stable when exposed to temperature changes and structural stress.

Check out Baltic Birch Plywood 5/8 x 20 x 30 on Amazon.

Why Is 5/8-inch Thick Plywood Recommended For Mobile Home Floors?

There are several structural components that constitute a completed floor. Initially, a joist or horizontal member is installed, distanced evenly to span the area to provide an attachment framework for the subfloor and the topmost finishing surface material.

The standard distance or span rating between floor joists in most mobile homes is 16 inches apart at their center.

A 5/8-inch thick plywood would adequately support and distribute the load based on this configuration. Thinner panels may prove too weak to accommodate foot traffic, furniture, heavy appliances, and other home fixtures.

This would also facilitate the use of longer fasteners to secure the plywood firmly on the joists and create a more stable and durable floor surface.

Water-resistant marine plywood is chemically treated for outdoor use and has been fortified to resist high moisture and humidity. Use this specialized material for your kitchen, bath, and laundry area to protect your floors against damage.

Are There Other Materials You Can Use?

OSB - Oriented strand board.

Oriented Strand Boards or OSB are engineered wood panels with similar characteristics to plywood. They are manufactured from wood strands, adhered and heat-cured to form lightweight but durable construction boards used for several purposes.

Larger prefabricated panels are available which makes installation faster and less complicated, especially for large areas.

The material is relatively thicker and heavier and creates a solid underlayer for hardwood, carpet, and other floor finishes. They are less expensive than plywood but just as versatile.

However, they tend to swell over time with prolonged exposure to humidity, and the surface appearance tends to be rough and uneven.

OSB is an alternative material to plywood, but its use and function may be limited to living areas, halls, and bedrooms and away from kitchens, baths, and laundry facilities.

Tongue and groove, or TnG, is actually a form of plywood that features a distinct configuration that allows installation without any fasteners. The design format of the slats simply fits together when the boards are positioned according to its structure.

They may actually be used as subfloors or as the surface material themselves and prove durable and stylish and attractive either way.

The only disadvantage of T&G is its cost, most materials are treated to withstand high humidity and temperature changes that tend to inflate its price. In the long run, it is definitely an option to consider.

How Do You Install Plywood Over A Mobile Home Floor?

Holiday, modern mobile home constructed from cardboard and plywood and aluminum,static caravan park in the middle of nature.

Installing plywood as an underlayment proves to be a more proficient alternative than the traditional material. That being said, there are certain guidelines you have to follow prior to the installation.


If you are considering using plywood for your mobile home floor, it is important to make the proper considerations to make the right approach.

Prior to installation, you must first determine the best lumber material and its specific function. Will the wood be used as a subfloor or an overlay? Should you remove the old underlayment, or can you just simply install the material over it?


This is where preparation comes into play. Since plywood is more durable and rigid as compared to particle boards, it is advisable to use the material as an overlay.

Clear the area by removing any structures and fixtures, such as furniture, carpets, and appliances. Baseboards and paneling should also be temporarily removed since they could get in the way of the installation process.

Clean The Subfloor

Wipe away any dirt, dust, and debris using a slightly damp cloth or paper towel to rid the surface of particles that may cause the flooring to be uneven. Be sure that the fabric is not too wet to prevent water from seeping into the subfloor.

Fix Uneven Surfaces

Worn-out subfloors tend to warp and expand over time. The course of action you need to take depends upon the extent of the damage.

You might have to remove the boards and replace them with new ones or sand minor bumps to make the surface level. Scrape any old glue and debris that prevent proper adhesion.

Acclimate The Plywood

Different rooms in your mobile home will generate different rates of humidity and moisture. The renovation space is the primary concern to acclimate the material of your choice.

Store the plywood for at least 72 hours before you begin the installation. This way, the wood can adapt to the room’s temperature and general condition.

Installation Process

To begin, place a piece of underlayment on all the corners, leaving at least 1/8-inch gap between the wall and the wood. The gap will accommodate shrinking and expansion.

Sand or trim the edges to fit the material more uniformly and avoid uneven contact.

You can fasten the boards using staples, screws, or nails. Staple every two inches around the outer edges and four inches in the inner portions. If you are using screws or nails, provide at least nine inches of space in between the fasteners.

It is best if the underlayment is situated 1/8-inch apart from each other, allowing expansion or shrinkage. Afterward, fill the gaps using a seam filler.

Since plywood appears unfinished, you can cover it with other floor covering such as carpet, hardwood, vinyl, and composite. The material then becomes the base or the subfloor as well.

What Is The Cheapest Flooring For A Mobile Home?

Laminate flooring is the most affordable but durable and long-lasting material for a mobile home.

Also dubbed as the floating floor, it is possible to install without attaching panels to the subfloor. Since this is the case, the material easily contracts and expands along with the temperature changes.

In Closing

The subfloor material for most mobile homes is constructed with standard particle boards, which are relatively susceptible to temperature and humidity changes. Replacing them with plywood alters the floor surface and offers a more structurally sound foundation. We hope the article has been informative.

You might also find these topics helpful:

Can You Paint Vinyl Siding On A Mobile Home? 

How To Install Carpet Over Plywood

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