How to Screed a Concrete Slab by Hand or Laser

✔ Step-by-Step: How to Screed a Concrete Slab by Hand or Laser

1. 1

   Set Your Finished Floor Levels

   Before you start pouring or screeding, clearly define your slab’s final height. Use a rotating laser level, string lines, or datum pegs. Mark levels on perimeter formwork or internal pins. These become your reference for how much concrete to add or take away as you screed. Consistent levels across the slab are crucial for drainage and floor flatness — never skip this step.

2. 2

   Pour and Rake Concrete Just Above Final Height

   As concrete is poured, use a rake or shovel to distribute it roughly to height. You want it slightly over your level mark to allow for compaction and cutting down with the screed. Don’t worry about perfect distribution yet — just make sure every section has enough material and no deep dips or dry patches. Vibrating the slab first? That comes just before screeding.

3. 3

   Start Hand Screeding from the Furthest Point

   With hand screeding, use a 2–2.5m aluminium or timber straightedge. One person pulls while the other watches and backfills. Start at the furthest edge and work back toward your exit. Keep the screed flat across your guides — whether that’s formwork, pins, or rails. Use a slight sawing motion to avoid tearing or digging into the surface. Fill in low spots with a shovel and re-pass if needed.

4. 4

   Use Wet Screed Pads or Pre-Pulled Rails

   Wet pads are small pre-levelled mounds of concrete placed along a line to act as a guide. You pull the screed across these to maintain depth. You can also use rails (e.g. angle iron or box section) set to level before pouring. Once screeded, you lift the rail and fill in the strip it leaves behind. This method keeps screed paths consistent and works especially well with laser-guided prep.

5. 5

   Laser Screeding with Tripods or Screed Rails

   For laser screeding, a receiver is mounted to a staff or screed rod, and matched to a laser spinning at a fixed datum. As you move across the slab, the receiver tells you if you’re high or low relative to target height. Some use laser-guided strike-off machines, but even a basic tripod and staff system lets you stay within millimetres. Best for slabs requiring ultra-precise levels — commercial floors, polished concrete, etc.

6. 6

   Check Surface with Straightedge as You Go

   As you move across the slab, pause every couple of metres to check your work. Run the screed bar back over previous sections and spot any humps or dips. Use a level or laser to confirm overall flatness. Surface consistency matters — especially if you’re polishing later or laying resin or tile. Don’t rely on visual judgement alone — verify with tools.

7. 7

   Float Immediately After Screeding

   Once screeding is complete and levels are confirmed, move straight to bull floating while the surface is still fresh. This closes pores, settles aggregate, and preps the slab for either power float or trowelling. Don’t let the surface crust — floating too late can cause surface tearing. Keep your tools clean and edges tight — now the real finishing work begins.