Leveling
The process of establishing a flat, even surface at the correct elevation during concrete placement
Leveling is the process of establishing a flat, even surface at the correct elevation during concrete placement. In flatwork, leveling encompasses screeding (initial strike-off), floating, and any adjustments needed to achieve the target grade. Self-leveling compounds extend the concept to thin-pour applications over existing floors.
Why It Matters
Level concrete is functional concrete. A slab that's not level pools water, creates tripping hazards, and looks unprofessional. For interior floors, even small deviations (1/4 inch over 10 feet) cause problems with flooring installation—tile won't lay flat, hardwood develops gaps, and vinyl shows every bump. Proper leveling during placement is far easier and cheaper than grinding or overlaying after the fact.
For exterior work, "level" actually means properly sloped for drainage. Patios, driveways, and sidewalks need 1/4 inch per foot (2%) minimum slope away from structures. Establishing this slope is part of the leveling process.
Technical Details
Leveling during placement:
- Set forms to desired grade using string lines and levels
- Screed (strike off) concrete to form tops
- Bull float to remove screeding marks and fill voids
- Hand float for final surface smoothness
- Laser levels provide most accurate grade control
Self-leveling compounds:
- Polymer-modified cement that flows to level under gravity
- Typical thickness: 1/4 to 1-1/2 inches
- Used over existing concrete, wood, or tile substrates
- Sets in 1-4 hours, full cure in 24 hours
- Requires primer on substrate for adhesion
- Cost: $1.50-3.00 per square foot at 1/4 inch thickness
Tolerance standards:
- Residential flatwork: 1/4 inch in 10 feet (F-number F25)
- Standard commercial: 1/8 inch in 10 feet (F-number F50)
- Warehouse/forklift: tighter tolerances (F-numbers F50-F100)
- Superflat floors: extreme tolerances for high-rack storage (F-number F100+)
Common leveling problems:
- Forms not set to grade — check with level before pour
- Insufficient screeding — must make multiple passes
- Concrete too stiff to screed properly — adjust slump at ordering
Related Terms
- Screeding - Primary leveling operation during placement
- Strike-Off - Initial leveling with screed board
- Floating - Fine leveling after screeding
Learn More
- How to Level Concrete - Complete leveling guide
- How to Pour Concrete - Leveling within the placement process
- Concrete Slab Calculator - Plan your slab project