Making a wooden floor even typically involves addressing the unevenness through a combination of assessment, preparation, and leveling techniques. The best approach depends on the severity of the unevenness and the type of flooring you plan to install over it.
Assessing the Unevenness
Before you start any work, thoroughly inspect the floor to identify the cause and extent of the problem.
- Use a long level or straightedge: Place it across the floor in multiple directions to identify high and low spots.
- Mark uneven areas: Use a pencil to circle or mark areas that need attention.
- Consider the underlying structure: Determine if the unevenness is due to subfloor issues (joists, plywood) or the flooring itself.
Methods for Leveling a Wooden Floor
Several methods can be used to level a wooden floor, depending on the severity of the unevenness and the desired outcome.
1. Covering with Hardboard or Plywood Underlayment
This method is suitable for minor imperfections and provides a smooth, even surface for installing new flooring.
- Process:
- Clean the existing floor thoroughly.
- Fasten hardboard or plywood sheets (typically ¼" or ½" thick) to the existing floor using nails or screws. Stagger the seams between sheets.
- Ensure the underlayment is securely fastened to the subfloor.
- Apply a floor leveler compound to fill any remaining seams or imperfections in the underlayment, creating a perfectly smooth surface.
- Pros: Relatively inexpensive and easy to install.
- Cons: Adds height to the floor, which may affect doorways or transitions to other rooms. Not suitable for large or numerous dips.
2. Using Self-Leveling Compound
Self-leveling compound is a pourable liquid that spreads out and hardens to create a level surface.
- Process:
- Prepare the floor by cleaning it and applying a primer.
- Mix the self-leveling compound according to the manufacturer's instructions.
- Pour the compound onto the floor, starting at the lowest point.
- Use a gauge rake or trowel to spread the compound evenly.
- Allow the compound to dry completely before installing new flooring.
- Pros: Effective for filling in larger dips and creating a perfectly level surface.
- Cons: Can be more expensive than underlayment. Requires careful preparation and application. Might not be suitable for significantly unlevel floors where joists need addressing.
3. Shimming
Shimming involves inserting thin pieces of wood or other material under the low spots of the floor to bring them up to the level of the surrounding areas. This is often done to address problems with the subfloor joists.
- Process:
- Locate the low spots in the floor.
- Lift the flooring in the affected area (if possible).
- Insert shims between the subfloor and the floor joists to raise the low spots.
- Secure the shims with construction adhesive or screws.
- Reinstall the flooring.
- Pros: Effective for addressing localized unevenness.
- Cons: More labor-intensive than other methods. Requires access to the subfloor.
4. Sanding
For minor surface imperfections in a wood floor, sanding can be effective in creating a more even surface. This is more relevant to solid wood floors, as you cannot sand a veneer too much without ruining it.
- Process:
- Rent or hire a floor sander.
- Use progressively finer grits of sandpaper to remove imperfections and create a smooth surface.
- Be careful not to sand too much in one area, which can create new unevenness.
- Refinish the floor after sanding.
- Pros: Can restore the appearance of the floor and remove minor imperfections.
- Cons: Requires specialized equipment and skills. Only suitable for solid wood floors.
5. Addressing Subfloor Issues
If the unevenness is due to structural problems with the subfloor, such as sagging or damaged joists, the underlying issues must be addressed. This may involve:
- Reinforcing or replacing joists: Sistering new joists alongside existing ones or replacing damaged joists entirely.
- Adding support posts: Installing support posts under the joists to prevent sagging.
- Replacing damaged subfloor panels: Replacing warped or damaged plywood or OSB subfloor panels.
Choosing the Right Method
The best method for leveling a wooden floor depends on the specific circumstances. Consider the following factors:
- Severity of the unevenness: For minor imperfections, underlayment or sanding may be sufficient. For larger dips or structural problems, self-leveling compound, shimming, or addressing subfloor issues may be necessary.
- Type of flooring: The type of flooring you plan to install will influence the best leveling method. Some flooring types, such as tile, require a perfectly level surface.
- Budget: Different methods have different costs associated with them.
- Skill level: Some methods require more skill and experience than others.
By carefully assessing the unevenness and choosing the appropriate leveling method, you can create a smooth, even surface for your new flooring.
