Laser Screed Floors: How They Work and When to Use One

A laser screed is a machine that places and levels a concrete floor to a laser reference in a single pass. It lets a contractor lay large slabs quickly while holding a tight flatness tolerance, which is why it is the standard method for warehouse and distribution centre floors.

You will see it written as laser screed, laserscreed and Laser Screed. They all mean the same plant and the same method. The best-known machines are made by Somero, and Trent runs its own Somero S22EZ. This guide explains how laser screeding works, what it achieves, and when it is worth it.

How a laser screed works

• A laser sets the level. A transmitter on site sweeps a reference plane across the floor area. Receivers on the machine's screed head read it continuously.
• The machine strikes off and vibrates. The screed head is pulled through the placed concrete, cutting it to level, consolidating it and leaving a flat surface, adjusting automatically to the laser as it goes.
• The floor is then power floated. Once the concrete has stiffened enough, power floats work the surface to give the dense, hard-wearing finish an industrial floor needs. See power float finish.

The level comes from the laser, not from hand-set rails or a straightedge, so the slab holds its tolerance across a much wider pour than hand methods can manage.

What a laser screed achieves

Two things at once: area and flatness. Hand methods can give you one or the other over a big floor plate, rarely both, and never quickly.

Outputs depend on concrete supply, slab thickness and the complexity of the project, such as access and reinforcement. Flatness classes come from the Concrete Society's Technical Report 34 (TR34), now in its 4th edition, which is what UK warehouse floor specifications point at. FM2 is typical on our laser screeded warehouse floors, though not on every floor.

Fewer joints, a more consistent floor

Because a laser screed can place wider pours, the floor needs fewer day joints. Joints are where industrial floors fail and where maintenance costs build up, so fewer is usually better, as long as the spacing still works with the slab design and the reinforcement. The surface is also more consistent from bay to bay, because the same machine and the same reference set the level everywhere.

When a laser screed is worth it

A laser screed earns its cost on area. Below a certain floor plate, the set-up and the plant movements cost more than they save, and a conventional pour is the better answer. Above it, the calculation turns quickly in its favour, especially when the building has to be handed to the racking installer or the fit-out on a fixed date.

It is the natural choice for:

• Warehouses and distribution centres, where flatness under racking and reach trucks is the whole specification.
• Manufacturing and industrial units with large, open floor plates.
• Data centre slabs, where the specification is tight and the programme is fixed.

What a laser screed pour needs from the site

• A sub-base that is flat and firm. The machine works on the prepared base. A loose or out-of-tolerance sub-base is paid for in concrete volume, a regulating operation, or a machine that cannot work properly.
• A watertight building with a clear run. Laser screeding wants long, uninterrupted pours. Columns, pits, drainage runs and unfinished steelwork all slow it down.
• Enough concrete, arriving on time. On a large pour the batching plant and the delivery route become the limit. Slabs are typically 150 to 250mm thick, and supplying more than 250 to 300m³ a day is hard, so resourcing for high output only makes sense if the supply can feed it.
• A settled specification. Agree the TR34 class, the slab design and the joint layout before the floor is priced. Area and grade together set the plant, the crew and the number of days.

Laser screed floors from Trent

Trent Construction Services lays laser screed and large pour concrete floors for main contractors across the UK, with our own Somero S22EZ, our own power floats and our own operatives. Floors are surveyed by an independent specialist flatness surveyor. We work on commercial projects only.

The detail is on our laser screed and large pour floors page. If you have a floor coming up, send us the drawings and the specification. Discuss your project.