A laser screed is a machine that levels freshly placed concrete to an exact elevation. A laser transmitter set up on site sends out a flat reference beam, receivers on the screed head read that beam many times a second, and the machine raises or lowers the head on its own as it pulls through the concrete. The result is a slab placed to the same grade from one end of the pour to the other, which is why laser screeds are the standard tool for warehouse floors, distribution centers and other large slabs on grade.
How a laser screed works
Every screed does the same basic job: it strikes off wet concrete to the right height so the finishers start from a flat surface. A hand screed does it with a straight board or a vibrating bar riding on forms or wet screed rails, and the crew sets the height by eye and string line. A laser screed takes that judgment out of the strike-off.
- The reference. A rotating laser transmitter on a tripod beside the pour sets a flat (or sloped) reference plane over the whole area.
- The receivers. Receivers on masts at each end of the screed head read the beam and tell the machine’s controls where the head sits relative to grade.
- The head. A plow cuts the concrete down to rough grade, an auger spreads the excess, and a vibrating strike-off consolidates and levels the surface as the head moves.
- The correction. Hydraulics adjust each end of the head continuously, so the screed holds grade even when the concrete in front of it is uneven.
There are two common types. Boom screeds, such as the Somero S-240 we run on large warehouse slabs, sit outside the area being placed and pull the head back toward the machine on a telescoping boom. Ride-on screeds, such as our Somero S-15EZ, drive across the reinforcing on wide tires and place concrete in tighter areas. Where a slab needs designed slopes or crowns, a 3D laser screed follows a 3D model of the surface instead of a single flat plane.
The benefits of laser screed concrete
Flatter, more level floors
The biggest reason owners specify laser screed placement is flatness. Floor flatness and levelness are measured with FF and FL numbers, and racking, forklifts and automated equipment all depend on them. Because the screed holds grade across the full width of the pour, the floor does not drift between hand-set screed rails. On our warehouse work we treat FF 50 / FL 35 as a baseline, and the method can go well beyond that when a spec calls for it. Our guide to FF and FL numbers explains what those figures mean.
Larger pours with fewer joints
A hand screed crew works in narrow strips between forms. A laser screed can place much wider areas in one pour, so the slab ends up with fewer construction joints. Fewer joints mean fewer edges for forklift wheels to break down and less joint maintenance over the life of the building.
Less corrective work
High spots left by a poor strike-off usually get ground off after the slab cures, and low spots collect water and cause racking to lean. Getting the grade right at placement avoids most of that grinding and patching, and the schedule does not carry a corrective line item after the concrete crew leaves.
Better use of the crew
The machine does the heaviest, most error-prone part of placement. That frees the crew to focus on consolidation, finishing and curing, which are what decide how the floor wears.
How fast does a laser screed work?
Fast enough that the screed is rarely what limits the day. On a large warehouse pour the pace is usually set by how quickly ready-mix trucks arrive, how many finishers are on the slab and how fast the concrete is setting in that day’s weather. A laser screed crew can place a large slab section in a single pour that a hand screed crew would split into several days of strips. Our crews place over a million square feet of commercial concrete a year with this equipment.
How long does a laser screed concrete floor take?
The placement itself happens in one day per pour section, but the whole floor takes longer because of the work around it:
- Before the pour: subgrade compaction, the stone base, edge forms, any vapor retarder, and the reinforcing or dowels the design calls for.
- Pour day: placement with the laser screed, then floating and power troweling the same day as the concrete sets.
- Within hours: saw cutting the control joints, usually the same day or night, before the slab starts to crack on its own.
- The following week: curing, with light foot traffic after a day or two and vehicles once the concrete reaches the strength the engineer specifies.
Laser screed vs other screeds
| Method | How grade is set | Best suited to |
|---|---|---|
| Hand or straightedge screed | Forms or wet screed rails, set by eye and string | Small pours, tight spaces, repairs |
| Vibratory or roller screed | Rides on forms on each side of a strip | Small to medium slabs poured in strips |
| Laser screed | Laser reference read by the machine, adjusted automatically | Large slabs on grade where flatness matters |
When a laser screed is not the right tool
Laser screeds pay off on large, open areas. For small pours, tight rooms full of columns or short pieces of flatwork, the mobilization costs more than it saves, and a good hand crew is the better answer. That is why we take on laser screed work from about 10,000 square feet up.
Planning a large slab?
Yoder Laser Concrete places warehouse floors and industrial slabs with our own Somero laser screeds across Ohio, Indiana, Michigan, West Virginia and Pennsylvania. See our warehouse floor work, or send us your plans and an estimator will reply within 24 hours. For background on the equipment itself, Somero builds the laser screeds most crews use.
