How to Level a Floor - Kitchen Cabinets

Leveling an uneven floor is an important process when installing new flooring or repairing an existing floor. Taking the time to properly level your floor ensures your flooring lays flat and looks its best. With some basic tools and the right techniques, leveling a floor is an achievable DIY project for most homeowners.

Materials and Tools Needed

To level a floor, you will need:

Leveling compound – Self-leveling or patch/skim coat leveling compound. Make sure it is suitable for your type of existing floor.
Trowels – A notched trowel for the self-leveler and a finishing trowel for the patch leveler.
Level or straightedge – An accurate 4 foot level or longer straightedge. A quality level is key.
Floor leveling bar – Helps spread self-leveling compounds. Can also use a notched rake.
Spiked shoes – Helps walk on the wet self-leveler without leaving indentations.
Mixing bucket & drill mixer – For mixing leveling compounds.
Primer – As recommended for floor and leveler type. Priming ensures proper adhesion.
Safety gear – Mask, gloves, and safety glasses. Leveling compounds are dusty and caustic.
Cleaning supplies – Broom, mop and bucket, mineral spirits, rags.

Step 1: Preparing and Cleaning the Floor

Proper prep is crucial for the leveling compound to properly fill in the low areas of the floor. The key steps include:

Remove existing floor coverings – Take up carpeting, tile, sheet vinyl, or worn boards. Scrape off all old adhesives.
Clean thoroughly – Sweep and mop the floor. Make sure the floor is free of waxes, oils, and any debris.
Fix squeaks & loose decking – Screw down any loose subfloor panels and add construction adhesive to quiet squeaks.
Hammer down protruding fasteners – Any nails or screws sticking up must be driven down flush.
Fill deep holes and cracks – Use hydraulic cement or wood filler as needed. Allow drying per product instructions.
Prime the floor – After sweeping and vacuuming up all dust, apply a compatible adhesive primer. Allow to dry completely.

Proper cleaning and priming ensures the leveler bonds well to the floor for a smooth finish.

Step 2: Find and Mark Out Low Spots

Mapping out the low spots and depressions allows you to judge how much leveling work is needed. Here is how to find the uneven areas:

Use a level and/or straightedge – Place the level and straightedge on the floor in multiple areas to reveal high and low points. Mark low areas.
Find low spots visually – Look closely along the floor from an oblique angle. Shadows and gaps under the straightedge make dips visible.
Circle trouble areas with chalk – Outline the perimeter of low spots so you know how much area to cover with the leveling compound.
Test using a string line – Stretch out a chalk line across the floor. Low spots will create larger gaps under the string.

Mark at least 6 inches beyond the low area perimeter. This provides space to feather out the leveler thinly.

Step 3: Mix and Pour Self-Leveling Compound

For floors more than 1/4″ out of level, a self-leveling product works best to smooth out larger low areas. Follow these tips:

Follow package directions – Carefully measure the water and gradually mix in the leveling powder.
Mix thoroughly – Continue mixing for several minutes until the compound is lump-free.
Only mix what you can use – Leveler sets up quickly, so mix smaller batches you can pour and spread right away.
Pour carefully – Pour the leveler slowly and evenly within the marked low spot. Spread gently into corners with a small trowel.
Spread evenly – Use the smoothing bar to distribute the leveler and help fill in edges.
Avoid leaving lines and ridges – Move the smoothing bar in small arcs rather than straight lines.
Watch for air bubbles – Lightly sweep the bar over the surface to pop bubbles.
Wear spiked shoes – Walk on the wet leveler carefully to avoid leaving dents.

Allow the self leveler to dry for 24 hours before proceeding. Then inspect for any remaining low spots.

Step 4: Apply Patching Compound

For minor low spots or smoothing smaller depressions, a thicker patching compound works well:

Follow package directions – Mix the powder and liquid components according to instructions.
Work quickly – Patch dries fast once mixed. Only mix what you can apply and smooth out within 10 minutes.
Spread with a trowel – Apply a thin, even layer using a notched trowel. Smooth with light pressure.
Feather edges – Blend the patch compound so it fades out thinly at the edges.
Make sure it’s flat – Look at the patch from an angle to ensure it has filled in the depression flush.
Let dry – Allow patch areas to dry for 2 hours before proceeding. Sand if needed.

Multiple thin coats are better than one thick coat for a seamless, flush patch. Allow each layer to dry before adding the next.

Step 5: Sand and Vacuum

Once fully cured, sanding and vacuuming ensures a smooth finished floor:

Allow full curing – Give the leveling compound at least 24 hours to fully harden before sanding.
Use a floor sander – A disk floor sander with 80 grit paper works best to smooth the area.
Sand edges lightly – Be careful not to damage edges of floor covering you plan to leave in place.
Hand sand hard to reach areas – Sand corners and along baseboards by hand.
Vacuum thoroughly – Use a shop vac to clean up all dust and grit after sanding before installing flooring.
Wipe with a damp cloth – Give the sanded floor a final wipedown to remove leftover dust.

Thorough vacuuming prevents humps or unevenness under new flooring from sand and debris under the leveler.

Step 6: Prime Again Before New Flooring

One final coat of primer prepares the surface for new floor covering installation:

Choose latex primer – A water-based primer works for most floor coverings and seals the leveling compound.
Apply evenly – Use a paint roller and extension handle to quickly prime the entire sanded surface.
Give it time to dry – Allow the primer to fully dry for at least 12 hours.
Test for moisture – Place a 2×2 plastic sheet taped down overnight to check for moisture before installing wood or other moisture-sensitive flooring.

Properly priming ensures maximum adhesion and prevents moisture issues under the new flooring.

Tips for a Smooth, Level Floor

Follow these additional pointers for best results leveling an uneven floor:

Test leveler on spare wood – Check that the compound doesn’t stain or react with your floor before applying broadly.
Isolate room – Close windows and doors and turn off HVAC systems to prevent drafts while pouring.
Allow longer drying times – Leveler may take longer to cure in cold or humid environments.
Work in sections – Divide large rooms into sections to provide better control and easier spreading/smoothing.
Pre-fill deep holes – Pack larger gaps and holes with wood filler before priming and leveling.
Follow expansion joint guidelines – Do not cover or fill expansion joints designed to control structural movement.
Hire a pro for extensive work – If you have large low spots or serious structural sagging, it may be best to bring in a floor leveling contractor.

Taking the time to properly level an uneven wood or concrete subfloor provides a flat, smooth, and attractive canvas for your new flooring. With some elbow grease and these DIY techniques, you can tackle leveling a floor in standard rooms or small areas. But for more extensive leveling work, don’t hesitate to call in the pros.

FAQ About How to Level a Floor

Here are answers to some frequently asked questions about leveling floors:

What is the easiest way to level a floor?

For minor unevenness, self-leveling compound is the easiest solution. Just mix, pour, and spread – the leveler does the work smoothing itself out. A smoothing bar helps spread and flatten it.

Can I use self-leveling compound on wood floors?

Yes, self-leveling products are designed to work over wood and concrete. Make sure the product you choose is recommended for wood. Primer helps it bond.

How do you level a badly uneven floor?

For floors with dips over 1 inch, it’s best to use a self-leveling underlayment. Pour it over the whole floor, feathering up to high spots. This fills in low areas to flatten the overall floor.

How thick can you apply self-leveling concrete?

Self-leveling compound can typically be poured from a feather-edge up to 1 inch thick per layer. Thicker is possible but more prone to cracking – multiple thinner layers is best.

Can I install vinyl flooring over self-leveling concrete?

Yes, leveled floors work well under vinyl plank, sheet vinyl, and linoleum flooring. Make sure the leveler is fully cured. Primer enhances adhesion of the new flooring.

How long does leveling compound take to dry?

Drying times vary based on thickness, temperature, and humidity. Most self-leveling products take 2-4 hours to dry for foot traffic and 24 hours for flooring installation. Patch compounds dry faster.

What can I use if I don’t want to use self-leveling compound?

Alternatives include wood floor leveling systems with shims or rectified gypsum-based underlayments that can be poured, pumped, or troweled. These work better over large areas than patch compounds.

Can I install hardwood flooring over leveled concrete?

Yes, provided moisture testing is acceptable. Make sure the leveler is fully cured and primed before laying wood flooring. Use a thin foam underlayment between the concrete and wood.

Can self-leveling compound be applied over tile?

In most cases self-leveling products cannot be applied directly over existing tile. The tile needs to be removed before applying leveler. Some polymers modified cement levelers can work.

How flat does a floor need to be for vinyl planks?

Vinyl plank flooring tolerates minor unevenness but dips over 1/4 inch should be leveled. The flatter the better for proper locking and seam avoidance. Self-leveler followed by patch ensures flatness.

Conclusion

Leveling an uneven floor takes work, but it is a necessary step before laying new flooring. Using the right materials and techniques, you can tackle this DIY project yourself and avoid paying more for a professional installation. Just focus on proper cleaning, priming, pre-filling, carefully mixing and smoothing the leveling compounds, and allowing full drying and sanding. With some elbow grease and patience, you can achieve a nice flat floor ready for your new vinyl plank, hardwood, tile, or carpet.