How much microcement do I need?

How microcement quantities are actually calculated

Microcement is sold by weight and applied by area, and the bridge between the two is consumption per square metre per coat. A KCBerry build-up is not one material but four in sequence, each with its own figure. KC Primer keys the coating to the substrate. Microcement Base goes on at roughly 1.2 kg/m² per pass, and it is always two passes with fibreglass mesh embedded between them — so 2.4 kg/m² in practice, or around 8–10 m² from a 20 kg bag. Then the finish: Microfinishing at about 0.6 kg/m² per coat, or Microtraffic at about 0.9 kg/m² per coat, again over two passes. Finally the 2K polyurethane sealer, which is what turns a mineral coating into a waterproof, cleanable surface.

That is why a Complete Kit is not simply "so many bags". Each kit is pre-portioned for its stated area across all four components, and because the finish coat is chosen at checkout, the kit ships a different bag count depending on whether you specify Microfinishing or Microtraffic. Buying the components separately is possible and sometimes right for a small repair, but for a whole room the kit is both cheaper and far harder to get wrong.

Why bathrooms are measured wall by wall

The single most common mistake we see is a customer quoting us their floor area. A 6 m² bathroom floor sounds like a small job until you add four walls at 2.4 m high, the shower enclosure, the vanity front and the splashback — and the project turns out to be 25 to 30 m² of coated surface. Measure each plane: length × height for every wall you intend to coat, length × width for the floor, and the shower separately because it may be specified in Micronoslip rather than the wall finish. Deduct only the large openings — a door or a window — and leave the small ones in; they cost you nothing and they buy you margin. Bathrooms also carry more sealed square metres per square metre of floor than any other room, which is the figure that surprises people costing their first project.

What changes when you go over tiles

Nothing, as far as quantity is concerned. Microcement bonds directly to sound ceramic and porcelain after priming, and it goes on at the same 2–3 mm total build, so a 20 m² tiled bathroom needs exactly the same materials as a 20 m² plastered one. What changes is preparation: tiles must be firmly bedded, degreased and primed, and any loose or drummy tile has to be removed and made good first. This is the whole commercial argument for microcement in a renovation — no demolition, no skip, no re-screeding, and a room that stays usable for most of the work.

When to add wastage

A trained applicator working a simple rectangular floor wastes very little. A first-time DIY applicator working a bathroom with a shower niche, a window reveal and an awkward corner wastes noticeably more — in mixing, in practice passes, and in the material that never quite makes it off the trowel. That is why the 10% allowance in the calculator is switched off by default and labelled as a recommendation: it is genuinely optional on a straightforward surface and genuinely sensible on a complicated one. If you are applying it yourself, or if the room has a lot of detail, take the 10%. Surplus material in the same colour batch is also useful insurance — colour is mixed per order, and matching a batch months later is not something we would promise.

Once you have your figure, the calculator above does the commercial part: larger kits carry a lower cost per square metre, so the cheapest answer is rarely the next size up. Compare it against the full pricing page, read the application guide before you order, and if the numbers matter commercially, send them to us — we check them for free.