How to Replace Subflooring in a Mobile Home

You will probably need to replace subflooring in a mobile home eventually, especially if it’s an older home or you have encountered a leak. The subflooring is not your carpet or vinyl, we’re talking about the wood under that.

In this article, you will learn the step-by-step process of replacing the subfloor in a mobile home. We have videos and images that will give you the visual information you need and, of course, in-depth descriptions and instructions on how to replace your subfloor.

What is the Subfloor in a Mobile Home?

For many years, mobile homes have been constructed with sub-flooring made of particle board which is made from sawdust and glue that essentially acts like a sponge when it gets wet. Even the least amount of dampness causes bowing, warping, rot, and soft spots.

replacing subflooring in a mobile home

Even in newer homes, where particle board wasn’t used, flooring can become warped or softened due to a small leak or routine encounters with water.

Most newer homes now use a higher grade plywood or OSB because it can withstand water better. Still, if you have a soft spot or bowing in any area it’s best to replace the subflooring in a mobile home quickly before it causes further damage.

Hopefully, this article will give you enough information to replace flooring in a mobile home yourself.

Of course, if you have any questions feel free to add them in the comments and I’ll do my best to help.


Is Replacing Flooring in a Mobile Home a DIY Project?

To replace flooring in a mobile home you will need experience in construction. This is not a job for someone that has never used a hammer.

On a scale of 1 to 10, I would rank it a 7 because no specialty tools are required and the material list is short but it is a tedious job and it must be done right.

replacing subflooring in a mobile home

Since you are dealing with major components of your home like plumbing, wiring, and walls a professional should be present. The image above shows the complex plumbing you may encounter in a mobile home bathroom.

The most difficult parts of the job are removing the old flooring, building out the perimeter joists, and keeping everything level.

We’ll deal with all of those issues in the step by step process below. if you can’t replace the subfloor yourself this article will at least show you what to expect when you hire someone else to do it.

updated single wide-subfloor
Cutting out the floor to replace it.

Material List

  • Plywood (3/4″ OR 5/8″)
  • 2X6 Lumber
  • Galvanized Screws
  • Liquid Nail Adhesive

Tool List

  • Circular Saw
  • Hammer
  • Pry Bar
  • Knife, Blade, Scraper

For bathroom or kitchens consider marine-grade plywood. It’s more expensive but it has waterproofing so it stands against water better.

Step-by-Step Process to Replace Flooring in a Mobile Home

This is a ‘quick and dirty’ list of the basic steps needed to replace flooring in a mobile home.

Step 1: Remove the Trim and Floor Covering

The first step to replacing rotted flooring in a mobile home is to remove the trim and floor covering.

If it’s carpet you will need to remove the strips. Vinyl will usually need to be cut around the perimeter of the room and tile will need to be ripped up.

Leaks Need to Be Repaired Before Going to the Next Step

If a leak caused rotting or flooring warping and bowing you must find it and repair it before moving on to the next step.

With the floor covering removed you will be able to trace the leak better. Follow the damage. Most of the time it will be a window or roofing issue and the water is running down the wall.

Bad toilet rings and damaged water supply lines are other common source of leaks in mobile homes. You can learn more about mobile home plumbing repair here.

Understanding Home Mobile Homes are Constructed

You may need to use a Dremel tool or knife to get the sub-flooring out from underneath the walls if the sub-flooring is damaged or rotted. If it’s healthy, you’ll likely want to leave the subflooring under the walls alone.

walls being installed over flooring in manufactured home construction factory (2)
The subfloor and floor covering are installed before the walls when a manufactured home is built.

Manufactured home builders construct homes in layers. All the flooring is laid before the walls are installed so chances are your flooring and floor covering will be under the entire wall.

Measure Your Subfloor Thickness

Next, you will need to measure your subfloor. Most subfloors are either 3/4″ or 5/8″ thick.

You will use the measurement to set your circular saw to the proper height. One of the most tedious parts of replacing subflooring in mobile homes is the removal of the original sub-flooring.

After you set your saw, you will carefully cut only the subfloor. Use caution so you don’t cut a joist. Here’s a video showing how to use a circular saw to cut out subflooring in a mobile home:

Step 2: Cut the Sub-Floor Out Around the Perimeter of the Room

If your flooring is 3/4″  set your circular saw to that and follow the perimeter along the edge of the room. You do not want to touch the joists below.

This is one of those tedious jobs no one likes to do!

Step 3: Cut the Sub-Flooring Between the Joists

Now that you’ve cut the sub-flooring around the edges, you will need to cut them down so you can remove them easier.

The smaller the pieces, the easier it is to get them out of your way. If you have ensured there are no pipes or wires between the joists you can simply saw between the joists and remove each piece. Remember to keep the saw set to the same thickness of the flooring to keep so you do not damage the joists.

If you can cut out an inch or so under the wall without damaging the wall you can slide the new sub-floor under the wall. This is the ideal method in the subflooring is rotted or weakened in any way.

DIY manufactured home remodel projects - replacing old subflooring in a mobile home kitchen

In the image below, the homeowners just cut the perimeter and left the original subflooring under the wall. This is fine since the flooring was not damaged under the wall.


Step 4: Inspect and Repair Joists

At this point, all the sub-flooring has been removed and you have a perfect opportunity to inspect the joists for any damage. If you do see damage,  you can reinforce it by adding an additional 2 x 6 to the original or removing and replacing.

If there’s not much damage, reinforcing is probably easier. Measure the space between the joists so you can cut the lumber (2×6) to the right length so they fit in between the joists.

Step 5: Add Insulation

This should be a top priority. Spending an extra $30 can save you a lot more in energy costs in the future. Remember, wiring and piping should be above the insulation so that the heat from the home can get to it.

add insulation under flooring in a mobile home 2
See the short joists? Those are placed where the new subfloor panels meet.

Step 6: Laying the New Sub-Flooring Down

Around the perimeter of the room, you will need to attach an additional 2 x 4 to the original so that you have a shelf or lip to lay the new sub-floor down, then nail and glue.

At each seam, where one piece of plywood ends and another begins, you will need to reinforce under it.

This means you will need to add a 2 x 4 between the original joists so you have a place to nail and glue down the plywood. You can see this happening in the photo above, where the small boards have been added between the long joists.

Sub-flooring should be laid in the same direction as the original, usually opposite the direction of the joists.

replacing subflooring in a mobile home
New subflooring in a mobile home.

Step 7: Install the New Floor Covering

Luckily, your choices are endless when it comes to floor covering for mobile homes.

If it’s in a bathroom, it’s probably best you go with a thick vinyl that has some protection against water will help protect your floor.

updated single wide-flooring during 3
New floor covering installed in a single wide.


Step 8: Enjoy Your New Floor

Congratulations, you have a great looking floor that will last for many years!

updated single wide-flooring after
New flooring in a mobile home.

It is complex to replace subflooring in a mobile home but it’s a common project for homeowners of older mobile homes. New subflooring, along with new insulation, will help your home last longer and save heating and cooling costs.

As always, thank you for reading Mobile Home Living!