Edge & perimeter curling
Curling Screed Edges: Why It Happens and How We Correct It
A screed edge that has lifted slightly and curled upward, usually along a wall line or at a threshold, is almost always a sign that one part of the floor dried faster than the rest of it.
Get a curling edge assessed
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Curling shows up most often at perimeters, thresholds and around columns — anywhere the screed's edge is exposed to a different drying environment than the middle of the room.
It's a differential shrinkage issue: the top and edges of the slab dry and shrink before the core does, and the mismatch pulls the edge upward by a millimetre or two. It looks alarming but it's a well-understood, manageable problem.
Below we cover why edges curl more than the field of the floor, how we measure it, and the grinding or filling correction that gets the floor flat enough for the next trade.
Why edges move more than the middle of the room
The perimeter of a pour has more exposed surface area relative to its volume, so it loses moisture faster than the centre of a large slab. That uneven drying rate creates a shrinkage gradient, and the edge lifts to relieve the stress.
Direct sun through a patio door, a draught under a temporary door, or a heater positioned near one wall all accelerate this on one side of a room more than another, making the curl worse in that zone specifically.
What we typically measure
1–4mm at the edge
Typical curl height
usually within 150–300mm of the wall
Distance affected
in the large majority of cases
Correctable by grinding
How we bring a curled edge back to level
- 1
Laser survey
We map the floor with a laser level to find every high edge, not just the obvious one.
- 2
Grind the high points
Diamond grinding brings curled edges down to the datum line without over-cutting the field.
- 3
Latex or leveller fill
Where grinding alone won't reach tolerance, a levelling compound tops up low areas beside the ground edge.
- 4
Re-check to SR1
Final laser check confirms the room is back within SR1 flatness before handover.
Get a curling edge assessed
Send photos of the affected wall lines and we'll advise whether it's a same-visit grind-and-level or something that needs a closer look first.
Grind-and-level vs full re-pour
Grind and level (usual route)
- Works for curls up to a few millimetres
- Same-day correction in most rooms
- No disruption to the rest of the build programme
Full re-pour (rare)
- Only needed where curling is severe and widespread
- Requires the original screed lifting first
- Adds weeks, not days, to the programme
Screed Curling at Edges — questions we get asked
Keep reading across the site
Get a curling edge assessed
Send photos of the affected wall lines and we'll advise whether it's a same-visit grind-and-level or something that needs a closer look first.