🏢Commercial Construction
Commercial Construction Grade Verification — Foundation and Slab Documentation
Verify foundation elevations, slab grades, and floor flatness (FF/FL numbers) to ACI 117 specifications with building department ready documentation.
The Problem
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Foundation elevation errors are expensive to fix
A foundation poured at the wrong elevation means costly remediation — shimming, grinding, or in the worst case demolition and repour. Systematic verification before the pour prevents this.
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Slab flatness disputes are common
FF/FL floor flatness disputes between GC and concrete contractor are extremely common. Without objective documentation taken immediately after placement, neither party has a strong position.
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Building department submittals require organized records
Commercial building departments require grade and elevation records at foundation and slab stages. Assembling these from field notes at project closeout is painful.
How Sitemark Solves It
Built for Commercial Construction Contractors
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Foundation Elevation Logging
Log foundation elevation at every column, pier, and wall — verify against structural drawings with pass/fail.
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Slab Grade Verification
Verify slab-on-grade elevations across the floor area — identify high spots and low spots before the concrete sets.
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F-Number (FF/FL) Documentation
Log floor flatness measurements on a grid and document FF/FL numbers for ACI 117 compliance.
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Anchor Bolt Layout Documentation
Log anchor bolt elevations and compare to structural drawings — catch errors before steel erection.
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Compaction Test Logger
Log compaction tests on subgrade and base before slab pour with automatic pass/fail vs specification.
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Structural Grade Report
Professional report format suitable for building department submittal and structural engineer review.
Equipment
Top Equipment for Commercial Construction
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Free Tools
Free Commercial Construction Calculators
F-Number Calculator
ACI 117 floor flatness FF and FL from elevation grid readings
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Compaction % Calculator
Field dry density vs Proctor for subgrade pass/fail
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Grade % Calculator
Calculate grade percentage from elevation difference
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Drainage Slope Minimum
Minimum drainage slopes for parking and site areas
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Standards & Compliance
Compliance Sitemark Helps You Document
ACI 117
ACI 117 floor flatness and levelness specifications — FF and FL numbers by facility type (conventional, moderately flat, flat, superflat).
IBC Structural
International Building Code structural grading requirements for foundations, slabs, and site work.
Local Building Code
Local building department requirements for grade verification at foundation and slab stages — varies by jurisdiction.
Structural Engineer Specs
Project-specific tolerances from the structural engineer of record — typically tighter than code minimums.
FAQ
What FF/FL numbers are typically required for commercial slabs?
ACI 117 defines several categories: Conventional (FF 20/FL 15), Moderately Flat (FF 25/FL 20), Flat (FF 35/FL 25), and Very Flat (FF 50/FL 35). Superflat floors for narrow-aisle warehouses may require FF 100+. Check your project specifications — the structural engineer specifies the required numbers. Higher FF/FL requires tighter grading control during concrete placement.
How soon after concrete placement should FF/FL measurements be taken?
ACI 117 requires FF/FL measurements within 72 hours of slab placement — before the concrete fully cures and while the contractor can still claim it meets spec. Measurements taken weeks later are not valid for ACI 117 compliance purposes. Sitemark logs the measurement date and time automatically.
How does Sitemark document foundation elevations for building departments?
Sitemark logs the design elevation, actual elevation, and tolerance result at each column, pier, and wall location. The foundation grade report shows all locations organized by grid coordinate or structure ID, with pass/fail status. This is the format building departments and structural engineers expect for elevation verification submittals.
What total station accuracy is needed for commercial foundation work?
Commercial foundation work typically requires ±0.005 ft (±1/16 inch) vertical accuracy. Robotic total stations like the Trimble S9, Leica TS16, and Topcon GT-1200 provide accuracy of ±0.003 ft or better at typical distances. For critical applications (post-tensioned slabs, machine foundations), verify your instrument accuracy against project specifications.
Can Sitemark document both the subgrade compaction and the foundation elevation in one job?
Yes. Sitemark's compaction test logger and shot logger both work within the same job record. Log your compaction tests on the subgrade, then log foundation elevations after the forms are set. Both are included in the final documentation submitted to the building department.
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