A fantastic floor starts with a level foundation. In this step-by-step guide, we’ll explore how to level an uneven subfloor in 10 easy steps, providing you with a smoother foundation for your next flooring project.
Dealing with an uneven subfloor can be a challenge, but with the right guidance and a bit of DIY spirit, you can achieve a level surface for your flooring.
While using a floor leveler will delay the start of your flooring installation by a day or two, working with a level subfloor makes your flooring project easier and increases the chance of success.
If you are looking for more help with hardwood flooring installation read the SureReno™ Basic Guide on Hardwood Flooring Installation.
Table of Contents
Assess the Subfloor
No floor is ever perfectly level, but not all subfloors require the use of a floor leveler. Use a floor leveler if you have deviations in the subfloor greater than 1⁄2” over 6 feet. To know if your subfloor requires leveling, thoroughly assess its condition. One trick is using golf balls or other perfectly round objects.
The golf balls will roll to the lowest spots in your subfloor. Then, using a 6’ long level, determine if the slope is greater than ½” over 6’. Identify all high and low spots, paying attention to any damage or irregularities that may impact the leveling process.
Gather Your Tools and Materials
Equip yourself with the necessary tools and materials for the job. You’ll likely need a straight edge, leveling compound, sandpaper, a trowel, a 6-foot-long level, screws, a drill, a planer, plywood, and a skim coat.
When learning how to level an uneven subfloor for the first time, SureReno™ ensures you have everything you need to get the job done.
Address High Spots First
Examine all the high spots on the subfloor. Sometimes the subfloor sheathing wasn’t screwed down properly and can be remedied by adding more floor screws. For minor high spots, gently sand the surface using medium-grit sandpaper. For substantial high spots, use a planer to carefully shave down the elevated areas.
Before using the planer, ensure all screws are removed or sunk well into the sheathing to avoid damaging the planer blade. Remember to wear safety glasses, noise protection, and gloves when using the planer.
Ensure Your Subfloor Sheathing is Sufficiently Fastened
Often, the original builder skimped on the number of screws used when fastening down the subfloor or missed the floor joists. Locate the joists at each end of the room and mark them using a chalk line.
Ensure there are adequate screws along each joist and along each seam of the subfloor sheathing. Properly fastening your subfloor to the joists will help prevent cracks in your mortar or squeaks in your wood floors.
Install Plywood for Substantial Leveling Problems
For more substantial leveling needs, cut and install plywood patches over low areas. Screw the plywood securely into the subfloor, ensuring a level surface.
Use ⅛” mahogany underlay, as it allows you to cut different size patches and layer them without protruding above the surrounding high spots.
Fill The Low Spots
Before applying the self-leveling compound, clean the subfloor thoroughly to ensure proper adhesion. Consider where the compound may flow, sealing any ducting registers or gaps around pipes.
Mix the self-leveling compound according to the manufacturer’s instructions for a lump-free consistency. Pour the compound onto the low spots of the uneven subfloor.
While it should be thin enough to flow and level itself, you may need to use a trowel to smooth the edges.
Work quickly, as self-leveling compounds have a limited working time.
SureReno Helpful Hints
The self-leveling compound, like the name suggests, should be thin enough to slowly flow and level itself, yet thick enough that you may need to help it. I like to make its consistence similar to that of a thin pancake batter.
Check for Levelness
Once the self-leveling compound is dry, use a level to check the overall levelness of the subfloor. Make any additional adjustments as needed to achieve a uniformly level surface.
If the subfloor still isn’t to your expectations, apply a second layer of leveler or a thin layer of a high-quality skim coat.
Allow for Proper Drying Time
Ensure you allow adequate drying time before proceeding with your flooring installation. Follow the manufacturer’s recommendations for the specific product you’ve chosen.
Final Check and Cleanup
Perform a final check for levelness, ensuring all areas are smooth and ready for flooring installation. Clean up any excess materials and debris from the leveling process.
Conclusion
Completing your flooring project properly will ensure your new floors look amazing for many years to come, providing a great source of pride knowing “you did this!” Plus, think of how much money you save by doing your own home renovations.
If you need additional details on the different types of self-leveling compounds, Ardex has put together a list of the various compounds and their properties, check it out: Self-Leveling Underlayments
Once this flooring project is complete, what will your next project be? Remember, no matter the project, SureReno™ will be there to ensure you start it with confidence.
Next, check out SureReno™ Guide To Installing Tile Floors
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