How to Replace a Subfloor Under a Wall
Replacing an underlayment under a wall is necessary when the underlayment is no longer structurally sound.
The subfloor is the solid foundation under the floor covering that it depends on for the stability of the floor and walls.
It is not the main support system, it is the work of beams, posts, and beams, but it does its part in the work.
Make Home Repairs a Breeze with These Reliable Tools!
Easy Way to Replace a Subfloor Under a Wall (DIY)
The subfloor can rot with water, usually the case with the walls behind the shower controls or the walls under the malfunctioning windows.
In some cases, you can remove parts of the subfloor without breaking down the wall.
Wall and Floor System Basics
The walls and floors are interconnected, creating a structurally rigid system. From bottom to top, the system will look like this:
- Beam: A beam is a long, horizontal piece of wood, usually two by eight or two by ten, that supports the floor.
- Base: The base is nailed to the top of the beam. Often 19/32 to 1/8 inch thick plywood or OSB, the subfloor can run continuously along the joist, or two sections of the subfloor can be in one joist.
- Basecoat: Some floors have a thin base coat that helps smooth the base of the floor covering. Not all floors will have this.
- Floor covering: Floor covering can be laminate flooring, vinyl tile, luxury vinyl plank, or any other type of flooring.
- Bottom wall plate: The bottom wall plate is the bottom of the wall. It is usually 2.5 meters long and two by four. Wall nails are driven vertically to the bottom wall plate. The wall plate itself is nailed (down) to the subfloor, with nails extending to the joist.
All items except the siding and floor covering are below and nailed to the bottom wall plate.
Removing the Subfloor Under Walls
Removing the subfloor while the wall is in place is difficult because the subfloor is stuck under the wall.
The process is similar to sliding a nailed book to the floor while a person is standing on it. This can be done but with some effort and patience.
- You can only remove part of the subfloor. To remove the subfloor from an entire wall, you will need to remove the wall.
- A safe width to remove is 14 inches, as it represents the space between two gaskets or two pins.
- When you find a rotten subfloor, you usually find that the rot spreads to the wall or other parts of the floor. So be prepared to replace more than just the subfloor.
What You'll Need
Equipment / Tools
- Flat prybar
- Circular saw
- Utility knife
- Oscillating multi-tool and metal blade
- Hand saw
- Drill
Instructions
1. Turn off the light and the water
At the electrical service panel, disconnect all circuits going to the area where the subfloor will be removed. Also close all affected water lines.
If you have middle water switches, turn off the water here. If not, turn off the whole house water at the main shutoff valve.
2. Remove footer
With the flat bar, carefully remove the baseboard and any quarter-turn trim. Put those pieces aside.
3. Remove the drywall sections
The drywall can be spread over the floor covering. In this case, cut a section with the necessary width and about 30 centimeters in height.
4. Remove the floor covering
Remove the floor covering directly over the subfloor you wish to remove. Also, remove a few more inches to make room for work. Some floor coverings will peel off, while others will need to be cut.
Laminate flooring and plush vinyl plank flooring installed parallel to the wall should lift easily. Self-adhesive vinyl tiles will peel off. The vinyl sheet can be removed.
It is necessary to break the ceramic and porcelain tiles and remove the fine mortar. Solid wood and artificial wood floors installed parallel to the wall can be removed, although some boards may be damaged.
5. Remove any underlayment
Some floors have a thin layer between the subfloor and the floor covering. For foam laminate flooring or felt liner, cut a section with the pocket knife.
For a 1/4-inch luan underlayment plate, set the circular saw to the correct depth to cut only into the luan, but not into any material underneath it.
6. Cut your nails
Attach the metal cutting blade to the oscillating multitool. Wearing eye and ear protection, turn on the tool and insert the blade under the bottom wall plate.
Cut all nails coming down from the bottom wall plate.
7. Cut the subfloor
Set the circular saw to the proper depth to cut only the subfloor, but none of the materials under the subfloor.
The circular saw cannot cut close to the wall, so cut as close as possible. Most circular saws allow you to cut up to 2.5 cm or 5 cm.
Continue two more cuts with the hand saw along the side of the cut square until you reach the bottom plate of the wall.
8. Remove the subfloor from under the wall
If the subfloor is badly rotten, you can pull the remaining section of the subfloor and remove it. If not, put a 3/4-inch drill into the drill and drill 3 1/2 inches deep below the bottom wall plate on both sides of the decayed area.
The bit acts effectively as a saw to cut through wood. If the edge of the subfloor rests on the joist, the subfloor section must be removed. Otherwise, proceed to the next step.
9. Remove the subfloor from the other side (optional)
If the subfloor is a continuous sheet that extends past the wall, you will not be able to pull the section you are working on. Repeat all of the above steps on the other side of the wall to free the subfloor for removal.
Ensuring a Strong Foundation for Your Floor
Replacing a subfloor under a wall can be a challenging project, but with the right approach and tools, it’s entirely manageable.
Taking the time to carefully follow each step will ensure your home’s structural integrity is maintained.
Remember, preparation is key: from shutting off utilities to using the right cutting techniques, each action contributes to a safe and successful subfloor replacement.
By understanding the connection between walls and flooring systems, you can execute the project efficiently and extend the life of your floors and walls.
We hope you enjoy watching this video about how to repair subflooring damage under a wall
Source: gregvancom
Did you find this post useful or inspiring? Save THIS PIN to your HOME Board on Pinterest! 😊
Once again, thank you for visiting our website!
We hope you've enjoyed exploring the content we've created for you.
Give yourself the chance to learn, get inspired, and have even more fun, keep browsing...
Last update on 2025-01-30 / Affiliate links / Images from Amazon Product Advertising API
More Home Tips 👇🏼👇🏼