The World is Flat! Floor Flatness and Levelness in Concrete Construction

Too often, concrete testing is focused on the plastic state of the material and the 28 days break. Testing for air, slump, temperature, and casting cylinders is only the start of achieving concrete quality. Depending on the application, additional concrete testing is needed for the success of the project. Placed concrete is not only part of the structure, but also the start of the work of other trades to make the space habitable. One of these tests is the evaluation of the Floor Flatness and Floor Levelness.

Understanding ASTM E1155 Standards

Floor Flatness (FF) and Floor Levelness (FL), together referred here as FF/FL, are determined in general accordance with ASTM E1155. This standard has been around since the early 1980s and has gone through many modifications over the years.

During the last three decades of the previous century, these values were measured using a 10-foot straight edge across the concrete surface. Repeatability of the test became a point of contention. As construction equipment and technologies progressed, construction precision increased and lessons were learned, more accurate measurements were needed.

The Difference Between Floor Flatness and Floor Levelness

Floor flatness is based on a statistical analysis of slope changes along a specified distance. The slope changes are calculated every 12 inches. In today's market there are pieces of equipment capable of reading the slope changes every inch or so. Essentially, FF is the "bumpiness" measurement along the concrete surface. Think about it as the number to determine if you will spill your coffee in the morning if you were to drive on it. The scale of measurement is fairly linear and typically ranges from 0 to 100.

Floor Levelness, although the determination of the values is calculated in a similar manner, this value relates more to the slope or inclination of the concrete surface. This value is critical in slabs-on-grade. For elevated slabs, the FL values could be deceiving as elevated slabs could be sloped in one or more directions.

Additionally, elevated slabs could experience small deformations depending on the support type, during the hardening/curing process of the concrete. Post-tensioned slabs will show different FL behavior than a slab on a metal deck or a lightweight concrete slab.

Critical Timing and Compliance Requirements

FF and FL numbers are important for the concrete structure quality, acceptance and future use. The FF and FL values must be taken within 72 hours of the concrete placement. Coordination between the concrete contractor and the testing laboratory is critical for compliance with ASTM E1155.

Omnant provides the contractor with the flexibility of remotely scheduling the testing laboratory to perform the Floor Flatness and Floor Levelness tests. Both values vary on a scale of 0 to 100. Typical FF and FL numbers depending on the application are tabulated in ACI 302.

Why Floor Flatness and Levelness Matter

So why does this matter for your projects? The FF and FL of the floor is important for the comfort of users, proper drainage, and critical for flooring contractors. Carpet, tile, and other floor covering installers rely on the FF and FL numbers to install the flooring materials. Can you imagine skating for the Stanley Cup (NHL) on bumpy ice? Or trying to get a 3-point shot to win the Larry O'Brien Trophy (NBA) on a tilted court? Just like athletes need consistent playing surfaces, your construction projects need reliable, flat floors to function properly.

As technology has evolved, the use of structures has changed considerably over the last decade. Many warehouses are automated these days. Automated equipment requires, in some cases, superflat floors. These measurements are an area of development in the current standards and our industry partners continue to work together to establish the boundaries and requirements for this type of construction materials testing.

How Omnant Simplifies FF/FL Testing

Currently, our Omnant users benefit from our easy-to-use platform to keep track of the equipment's calibrations, maintenance, and usage. Since these are very precise measurements, it requires precise, calibrated, and well-maintained equipment.

These tests also need patience and a very strong neck! Some manufacturers provide their own reporting tool as part of the equipment purchase, and Omnant is able to integrate custom forms of reporting to meet your clients' needs. Omnant simplifies the process from an easy scheduling to ensuring the equipment is ready to provide 24/7 access to the reports.

Regardless of your project complexity, Omnant is here to make sure your testing operations are accurate, precise, consistent, reliable, and profitable. Schedule a free Omnant demo today!