Guide

Replace your floor without demolition

Breaking out an old floor means noise, dust and rubble, and a new screed before the new floor can go down. Microcement goes over the floor you already have, 1–2 mm thick, so in many rooms the old floor can stay where it is. It does not work over every floor, though, and this guide covers both: when it works, and when it will not.

What it can go over

• —Ceramic tiles that are firmly bonded, with no hollow or loose tiles.
• —An existing terrazzo floor that is sound, with no cracked or loose sections.
• —Concrete and cement screed that has fully dried and cured, and is sound, not dusty or crumbling.

What the old floor must be like

• —Sound and firmly bonded. Tap across the floor with a coin or the handle of a screwdriver. A hollow sound means a tile has come loose from its bed. Those tiles must be fixed, or removed and the gap filled, first: microcement bonds to the tile, and cannot hold a loose tile down.
• —Dry. The surface must be clean, dry and free from damp when work starts. Surface Primer helps protect against damp, but it does not solve a floor with water coming up through it.
• —Clean. Grease, wax, soap film, old sealers and polish stop anything from bonding, and have to come off first.
• —Stable. No cracks that are still moving. See Cracked floors.
• —Reasonably flat. Two coats come to 1–2 mm, and they follow the floor you have. They will not level a floor that slopes or dips, or one where tile edges stand proud.
• —Grout lines. On a tiled floor, the joints are bridged with Surface Primer and Fibermesh before the microcement goes on.

When it will not work

• —Hollow, loose or cracked tiles across much of the floor. At that point the old floor is not a sound base, and taking it up is the honest answer.
• —Rising damp, or water coming through the slab. Fix the cause first.
• —Cracks that open, close or grow. A coating over a moving crack will crack again.
• —Timber, vinyl, or any floor that flexes. This guide covers mineral floors: tile, terrazzo and concrete. For anything else, ask us before you buy.
• —A floor that needs levelling. 1–2 mm will not hide a slope or a dip.
• —Pools and permanently submerged areas with Microcement Extreme. Those need Microcement Aqua.

The system, in order

1. 1
   Surface PrimerAlways the first layer. It stabilises the old surface, evens out how much it absorbs, and helps protect against damp. One 4 L tin covers 32–40 m² for one coat.
2. 2
   FibermeshA fiberglass reinforcement mesh embedded in the base coat. Strongly recommended for floors and large areas, and on an old tiled floor it is what bridges the grout lines. Sold in rolls of 50 × 1 m.
3. 3
   Microcement Extreme — or Microcement Aqua under waterTwo thin coats with a steel trowel or a roller, 1–2 mm in total. Microcement Extreme is for floors and walls, including bathrooms and other wet areas with the correct top coat. Microcement Aqua is for pools, pool surrounds, outdoor showers and areas under constant water. One 15 kg pack covers 9–10 m² for two coats.
4. 4
   Top coatThe protective layer that finishes every project: Topcoat, a water-based acrylic with a satin finish, or Ultran Super Enamel, a two-component polyurethane with a matte finish for interior and exterior floors.

Doors, thresholds and skirting

Because the whole system is only a couple of millimetres thick, most doors still close without being trimmed, thresholds stay almost level with the next room, and there is barely a step where the new floor meets the old one. Check any door with very little clearance underneath before you start. Microcement can also continue from the floor up the wall as a seamless skirting.

How much you need

Coverage depends on how absorbent and how flat your floor is. The product calculator works out the units for your area — primer, mesh, microcement and top coat. Treat the result as an estimate, not a quote. Prices are on each product page.