Forty Bags of Liquid Floor: The Leveling Pour

Day forty-six. The single most transformative day for how this house will feel underfoot — and 70% of it was preparation.

The damming. Self-leveling mortar’s virtue is its vice: it flows like water, which means it escapes like water. Any hole — door gaps, wall-base cracks, and especially the long empty track where the main windows will sit — becomes a drain. So the morning went to a full perimeter seal: urethane foam, tile adhesive, and silicone deployed everywhere air could pass. Where the floor steps too much for one pour, we built little dams from battens and silicone to divide the zones. This tedium took far longer than expected and determined everything. (Cleaning note: sweep thoroughly, but skip the wet mop — dust-free matters, damp doesn’t.)

The pour. The annex’s worst sag — around 3 cm — got a first pass of stiff-mixed mortar as a base fill. Then the main event, viscosity dropped to “melted chocolate”: mix five bags at a time in a big tub with a proper paddle mixer (mixing takes longer than you think — the aggregate must fully disperse), pour in bold passes, and tap-tap the surface with the spreader bar, coaxing rather than dragging, until the liquid finds its own level. Depth-strategy in one line: the deeper the zone, the stiffer the mix; our product’s ceiling was 3 cm, printed right on the bag.

The reckoning: 40 bags of Hanil SL30 (₩12,600 each), two people, eight hours including prep — roughly ₩1 million all-in for about 20 pyeong (66 m²). One overnight cure, and a house that has never once been flat in seventy years now has a floor like still water. The laser level, sweeping across it at the end, finally had nothing to report.

Everything from here — the wood floors, the furniture, the way footsteps sound — stands on today.