MICROCEMENT USA
MICROCEMENT USA
Topcret USA / Surfaces / Substrate prep
A reference for evaluating and preparing surfaces before any Topcret system is installed. The finish is only as good as what's underneath.
These guidelines cover the evaluation and preparation of substrates before installing any Topcret microcement system. They apply to floors, walls, ceilings and stairs, in residential and commercial settings, interior and exterior. System performance depends directly on substrate condition and preparation quality.
Every surface should be inspected to determine the right preparation protocol. Before evaluation, surfaces must be clean, exposed and unobstructed, and any existing finishes or contaminants must be identifiable.
Rising moisture and vapor pressure from beneath the substrate are the primary risk factors affecting system performance. They cause loss of adhesion, osmotic blistering, delamination, efflorescence and cracking, and characteristically appear weeks, months or seasons after installation.
Moisture must be measured to recognized U.S. standards, within the framework of ASTM F710, before any system is installed. The acceptance criteria, the test methods and the required test density are set out in Section 4.2 of SPG-US-v1.1 and are not reproduced here, so that a single set of figures governs. A handheld pin or pinless moisture meter is a screening tool only and is never an acceptable basis for a decision to proceed.
Substrates must be free of dust, grease, oils, solvents, adhesives, plaster, soap or shampoo residue, and any foreign material that affects adhesion. During application, avoid airborne dust and direct wind carrying particles, which can affect finish quality and cohesion.
Topcret microcement systems are not self-leveling and are not designed to fill or create slopes. Applied in roughly 7–9 thin layers (about 1/8 inch total), the system replicates the existing geometry — any irregularity transfers to the final finish. All leveling and drainage slopes must be corrected and verified before installation; poor drainage can cause water accumulation, mineral deposits (exterior) or residue marks (interior wet areas).
Concrete / self-leveling / microtopping. Must be structurally sound, fully cured (ideally 28+ days), flat, clean and dry, with a damp-proof membrane. Mechanically clean and vacuum; remove sealers, paints, varnishes and chemical residues (grinding or sanding recommended); treat all cracks at the source so they don't reflect through.
Tile. Tiles must be clean, degreased and fully bonded. Remove loose tiles and fill voids; for deep joints or uneven transitions, apply a thinset leveling layer to improve planimetry and prevent joint telegraphing.
Plywood (floors). Panels must be securely fastened and stable. Seal and fill panel joints, and apply a self-leveling floor underlayment to create a rigid, deflection-free surface.
Walls & ceilings. Drywall, Durock, cement board, DensShield or equivalent. Panels fully secured, screws flush and concealed, joints taped, filled and finished with plaster. Treat all wall-to-wall, wall-to-ceiling and wall-to-floor transitions; complete final leveling before application.
Wet areas & waterproofing. Microcement is not a waterproofing system. In showers, wet rooms, steam rooms, tub surrounds, balconies, terraces, roof decks, pools and exterior surfaces, a code-compliant, independently tested waterproofing assembly must be installed beneath the microcement by others, flood-tested and documented before installation begins. Any membrane beneath microcement must be rigid and non-flexible; cement-based systems give the best cohesion. Topcret USA does not design, install or warrant waterproofing.
Stairs. For wooden stairs, each tread must be a single solid piece, screwed and bonded, with no movement between tread and riser. Fill joints with rigid fillers (Bondo-type); flexible materials like caulk or silicone are not permitted.
Microcement must never be installed over flexible substrates or materials. Performance depends entirely on substrate stability and preparation; improper prep can cause cracking, delamination or aesthetic defects. No system can compensate for structural deficiencies, moisture issues or improper leveling.
Where Topcret USA does not perform the installation, substrate evaluation, testing, preparation and the decision whether to proceed are the sole responsibility of the installer or contractor. Where Topcret USA performs the installation, it records the substrate evaluation in a Substrate Condition Report signed by the customer; the substrate itself remains the responsibility of the customer and its trades. In both cases, the party that prepares the substrate is responsible for it. This page and SPG-US-v1.1 set the standard; they do not transfer the obligation, and they create no warranty.