Self-levelling — a flat floor from one pour
"Self-levelling" does not mean it levels itself unaided — it means it gives you minutes to help it flow before it starts to set. A successful pour is decided before the first bag opens: the right primer, tight dams, and a mixer plus a helper that keep the pour continuous.
Preparation: primer and dams
Grind the laitance, sweep, wipe — then acrylic primer is mandatory on cementitious substrates: without it the surface robs the compound's water, the flow dies where it lands, and rising air pits the face. Let the primer dry to a continuous film (2–4 hours). Dam every escape: door thresholds with stop bead, drains and pipe openings collared — the compound finds any hole you forget.
Mixing and pouring wet-on-wet
Water to the bag's figure exactly — self-leveller punishes excess water harder than any other material: it separates into a foamy skin over a weak body. Mix two minutes, rest one, remix. Then pour in parallel strips that meet while wet: the next bag must reach an edge that is still fluid, which is why mixing and pouring is a two-person production line, never one. The thickness figures on the bag (typically 2–10 mm per pour) are limits you respect.
Cross the fresh pour with the spiked roller — it releases trapped air and welds the meeting lines of successive pours. Spiked shoes if you must walk in it.
After the pour
Close the door: draught is the pour's first enemy — it dries the face before the body, so it peels or wrinkles. No direct sun through a window onto it. Walk-on after ~4 hours, tile over from the next day typically, and moisture-sensitive floors (parquet, vinyl) wait for measured — not eyeballed — dryness.
The pour mistakes with no later fix
- No primer: pinholes, dead flow, a pitted face.
- Extra water "to make it flow" — a foamy skin over a weak body.
- A slow one-person pour: edges set before the next bag arrives and stay as lines.
- A forgotten threshold or drain.
- Draught or direct sun on the fresh pour.
Frequently asked
Is self-leveller a finished floor?
Standard levelling compounds are an underlayment for tile, parquet or vinyl, not a wear surface — a finished floor needs dedicated wear-rated compounds.
Over underfloor heating?
Yes — it is the standard way to encapsulate electric heating mats before tiling — with the heating off before and during the pour, and the same gradual heat-up schedule after drying.
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Last updated: 2026-08-09