replacing subfloor

Sometimes, you might discover yourself in a position where replacing subfloor under a wall becomes essential. Generally, this occurs when the subfloor has been vandalized by water or is no longer healthy enough to sustain the weight it’s implied to. The subfloor is like the unsung hero under your floor covering, providing crucial strength for a room’s floor and walls. While it’s not the immediate support system, it does its fair percentage of the heavy lifting.

The subfloor prong may ring like a considerable task. In some cases, it can be quite a significant undertaking. There are illustrations where you can escape the whole wall to replace portions of the subfloor. Which means that, relying on the extent of the damage and the exact possibilities you can manage the subfloor matter without generating substantial trouble.

replace subfloor under wall

Wall and Floor Basics

Let’s split down the basics of walls and floors in an understandable manner. These two elements work jointly to form a solid design in your home. Here’s a simplified outline from the bottom up:

  • Joist: Assume the floor joist is your flooring system’s prostrate backbone. It’s an extended piece of timber that keeps your floor, generally 2×8 or 2×10 inches.
  • Subfloor: The subfloor is like the basis for your floor. It’s connected to the lid of the joists. Usually created of plywood or OSB (oriented strand board), the subfloor can range in consistency, varying from 19/32-inch to 1 1/8-inch. The subfloor runs constantly across the joists; in other cases, two subfloor branches meet on a beam.
  • Underlayment: Not all floors have an underlayment. It’s an insubstantial coating added to help smoothen out the subfloor before the last floor caching is established.
  • Floor Covering: The floor covering is what you see and walk on. It can be laminate flooring, vinyl tiles, luxury vinyl planks, or any other material you select for your area.
  • Bottom Wall Plate: This is the lowest part of the wall. It’s usually an 8-foot-long, 2×4 piece of wood. Wall studs are upright pieces of timber that drive up the wall’s framework and are connected to the lowest wall plate. The wall plate is securely attached to the subfloor. The nails even raise into the joist for counted strength. Everything noted, besides the underlayment and bottom covering, is situated under and arrived at the lowest wall plate.

Tip: After you’ve removed the existing subfloor, it’s advisable to use pins when seating the replacing subfloor. This supports preventing undesirable floor movement and underestimates the threat of breaks evolving in the plywood. For 3/4 inch plywood replacing subfloors that concede with construction principles, appropriate screw choices include #8, #9, #10, or #12.

Removing the Subfloor Under Walls

Taking out the subfloor under the wall can be tricky work since the subfloor is usually wedged under the wall design. It’s akin to stretching to skate out a book firmly nailed to the floor while someone is standing on it. While it’s not unbelievable, it requires much effort and tolerance. It’s important to note that you can only remove a portion of the subfloor if you plan to keep the wall intact. The wall must be removed to replace subfloor that drives under an exclusive fence. A secure width for removal is about 14 inches, as this commonly aligns with the distance between two joists or studs.

Although it might appear tempting to undertake the subfloor replacement from underneath, mainly if there’s a ticket to the basement area. Replacing subfloor from the top is typically suggested. The methodology involves:

  • Removing the subfloor hiding and any underlayment above it.
  • Cutting out the old subfloor.
  • Installing the latest material.
replacing subfloor under wall

Before You Begin

Before you tackle the replacing subfloor voyage, take the subsequent precautions:

  • Electrical Safety: At the electric service panel, twist off any circuits that power the space where you’ll be replacing subfloor. This stage is essential for your safety.
  • Water Shut-Off: Shut off any water pipes driving through the area. Use the water if you have intermediary water shut-off valves. If not, consider closing the water supply to the house using the main shut-off valve.

Following these security measures, you can proceed with assurance as you dive into replacing the subfloor.

What You’ll Need

Tools and Equipment

  • Flat Pry Bar: A balanced pry bar will be valid for removing materials and isolating components.
  • Circular Saw: A circular saw is essential for creating accurate and refined cuts.
  • Utility Knife: A utility knife is beneficial for cutting materials with accuracy and exactness.
  • Oscillating Multi-Tool and Metal Blade: An oscillating multi-tool fitted with a metal edge is adaptable and can handle mixed cutting chores.
  • Hand Saw: A hand saw delivers an alternative cutting opportunity when exactitude is needed.
  • Drill: A drill is adaptable for dull spots and fastening materials.
  • Nail Puller: A nail puller will help in removing pins and clasps.


  • Heavy-Duty Trash Bags: Heavy-duty trash bags are necessary for disposing of trash and waste materials.
  • Eye Protection: Protect your eyes adequately to prevent potential risks.
  • Ear Protection: Use ear defense to shield your ears from noisy noises and keep listening safety.


How to Replace Subfloor Under a Wall

Step 1: Remove the Baseboard

Begin gently operating a balanced pry bar to remove the baseboard and any quarter-round edge near where you plan to replace the subfloor. Set these removed parts aside for afterward.

Step 2: Remove Sections of Drywall

The following stage concerns removing areas of drywall. The drywall may spread over the floor surface. In this case, carefully cut away a section to the needed width and around 1 foot tall. Dispose of any resultant debris in a heavy-duty trash pack.

Step 3: Remove the Floor Covering

Remove the floor covering instantly above the subfloor that needs replacement. Remove a few extra inches above this area to provide ample working room. The comfort of removal differs depending on the type of floor covering you have:

  • Laminate and indulgence vinyl plank flooring seated parallel to the wall can generally be raised off.
  • Self-adhesive vinyl tiles can be skinned away, while sheet vinyl can be drawn back.
  • These must be shattered for ceramic and porcelain tile, and the expansive mortar that connects them should be chipped away.
  • Solid hardwood and arranged wood flooring installed similar to the wall can be levered off, though some panels may suffer harm.
replacing subfloor

Step 4: Remove Any Underlayment

Precise floors may have a light underlayment between the subfloor and the covering. Cut away a faction using a utility knife for laminate flooring with a foam or felt underlayment. You can set the circular saw to a suitable depth to cut only into it without involving the materials under if you have a 1/4-inch luan underlayment panel.

Step 5: Cut Away the Nails

Connect a metal-cutting edge to the oscillating multi-tool. While fraying proper eye and hearing safety, trigger the tool and insert the knife under the wall’s bottom container. Proceed to cut out all the nails that run below from the bottom wall plate.

Tip: If you favor, you can use a nail puller to drill into the wood around the nail leader. It allows you to pull the pin out instead of cutting it. This will remove the plug, stopping potential hang-ups during the subfloor replacement.

Step 6: Cut Away the Subfloor

Appoint the circular saw to a suitable depth to miss only through the subfloor, not the materials under it. Be aware that the circular saw cannot cut bloom with the wall, so cut as near as likely—most saws can handle an inch or two. Follow up with two different cuts using a hand saw along the flank of the cut-out court until you reach the wall’s bottom plate.

Step 7: Remove the Subfloor From Under the Wall

If your subfloor is exceptionally spoiled, you can remove the remaining area of the subfloor manually. But if this isn’t possible, hook a 3/4-inch drill bit to the routine and drill to a depth of 3 1/2 inches under the wall’s bottom plate on both sides of the vandalized area. The auger bit acts as a saw, etching away at the wood. The site should pull out if the subfloor’s border rests on the joist. If not, proceed to the next step.

Step 8: Remove Subfloor From the Other Side (If Necessary)

In cases where the subfloor is a constant sheet expanding beyond the wall, removing the section you’re operating on may be challenging. Repeat all the previously noted steps on the other side of the wall to free up the subfloor, allowing its removal.

When to Call a Professional

When confronted with replacing the whole subfloor beneath an exterior or load-bearing wall. It’s advisable to believe in hiring a professional. These designs require particular attention to ensure that the walls stay structurally sound and don’t sag or shift while the subfloor is temporarily removed for replacement.

For smaller subfloor areas, typically those up to about 14 inches broad between joists. Cutting out and replacing subfloor without further structural reinforcement is often possible. A DIY method may be more effortless.

replacing subfloor


Is Replacing a Subfloor Difficult?

Replacing subfloor is relatively easy to understand but undeniably labor-intensive and time-consuming. For people embarking on this job as a DIY project, it’s crucial to have a high level of convenience with removing and reinstating flooring, drywall, and trim before venturing on the trial.

What’s the Cost of Removing and Replacing a Subfloor?

The cost of replacing subfloor hinges on several aspects. Including the period of subfloor replacement needed and the selected material. Replacing subfloor with traditional plywood costs around $1.50 per square foot, tallying around $594 when factoring in labor.

Do Walls Rest on the Subfloor?

Walls are built atop a home’s subfloor. Therefore, when replacing the subfloor, there may be illustrations where the walls must be temporarily removed to facilitate the operation.

How to Replace Subfloor Under a Wall?

Replacing a subfloor situated under wall needs careful planning and implementation. To essay on this duty, you’ll need to pursue a series of steps, including clearing baseboards, cutting areas of drywall, removing the floor covering, and finally replacing subfloor. It’s vital to exercise warning and be assured that the wall’s structural virtue remains unharmed during the process.

How to Clean Subfloor After Removing Carpet?

Cleaning the subfloor after removing the carpet is vital in organizing it for further treatment. Remove any residual carpet padding and glue. Next, sweep and vacuum the subfloor to stop dust and debris. Use a wet cloth or appropriate cleaning solution to remove any remaining stains or remains if necessary. This practice ensures a clean and soft surface for any next flooring installation.

Can I Put New Subfloor Over Old Subfloor?

Installing a new subfloor over the old one is expected in many renovation projects. There are some primary references to keep in mind:

  1. Assure the current subfloor is in good shape and free from cracks or structural problems.
  2. Consider the height of the floor and doorways, as counting a new subfloor can raise the floor’s dimensions.
  3. Ensure that your chosen flooring material and local construction principles permit this method.

In many cases, it’s a possible option to save time and struggle in the renovation process.

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