Collection: Cement, Mortar & Concrete Mixes

A screed is used to build up levels and create falls — it’s structural and often thicker (10–100 mm). A self-levelling compound is a fine, flowable topping (1–15 mm) used for surface correction before tiling or coating. A repair mortar is designed for patching localised defects or reinstating concrete integrity. Choosing the right one depends on whether you’re building up, flattening, or repairing.

Only after it’s fully cured, dimensionally stable, and free of shrinkage cracks. Cementitious materials continue to hydrate and shrink as they dry, so premature membrane application can cause delamination. Fast-drying mortars (like Mapecem Quickpatch or Topcem Pronto) can accept waterproofing after as little as 24 hours, but always confirm the product’s minimum cure window in the TDS.

Yes — primers are crucial for bond strength and moisture control. Use acrylic primers (e.g. Primer G) for absorbent substrates, and epoxy primers (e.g. Planiseal MR) where moisture or hydrostatic pressure is present. Priming prevents rapid suction, dusting, and pinholes, ensuring an even cure and consistent adhesion.

Use a polymer-modified or pre-blended screed such as Topcem Pronto that offers reduced shrinkage and improved flexural strength. Always ensure proper falls (1:80 minimum), mechanical keying, and curing. Avoid general-purpose sand-cement mixes outdoors, as they’re prone to cracking, shrinkage, and debonding under temperature swings.

Yes — rapid mortars like Planitop Fast 330 or Nivorapid are perfect for localised slope correction or pre-membrane build-ups. They bond strongly to concrete and can be overcoated once fully cured. For waterproofing applications, lightly sand or abrade any glossy finish to ensure the membrane bonds properly.

Cracking usually results from poor curing, rapid drying, or excessive water in the mix. Use controlled-shrinkage formulations (like Topcem or Mapecem), maintain proper curing conditions (shade, damp hessian, or curing compound), and ensure movement joints are honoured through the screed. Never use high water content for workability — it weakens the matrix and accelerates shrinkage.

No — cement mixes are too rigid and alkaline, which can compromise membrane adhesion. Always use compatible polymer-modified mortars designed for overlay or remedial build-ups. If screeding over an existing membrane, introduce a bond-breaker layer (e.g. slip sheet or fleece) or use a floating screed system to prevent stress transfer.

Moisture testing is essential — use a Tramex or calcium-chloride test. As a guide, cement screeds dry at roughly 1 mm per day up to 40 mm, longer for thicker sections or cooler conditions. Fast-drying screeds like Topcem Pronto significantly reduce waiting time, but readings must still be below the manufacturer’s maximum (usually ≤ 5% moisture for membranes, ≤ 3% for adhesives).

Yes — polypropylene fibres help control micro-cracking, and latex admixtures (e.g. Planicrete SP) enhance flexural strength and adhesion. Always adjust the water ratio to compensate and mix mechanically for uniform dispersion. Avoid untested on-site cocktails of additives, as over-modification can reduce workability or compromise cure performance.