Microcement External Worktop Application

How to apply your Outdoor Microcement Worktop Kit

Outdoor worktops use a 3-coat system with mesh reinforcement throughout. Read these steps in full before you start. Wear gloves, a mask and old clothing throughout.

1. Prepare your cement board substrate The cement board must be mechanically fixed (screwed) to a structurally sound substructure — masonry, timber or otherwise. Leave a 3mm gap between each board section.

2. Fill the joints with resin Apply exterior-grade polyester anchor resin into the 3mm gaps between boards using a caulking gun. Strike off level with the board surface before it cures. Work in small sections — resin sets quickly.

3. Apply Primer (coat 1 of 3) Once the resin has fully cured, apply the first coat of Microcement Primer across the entire surface. Allow to dry fully. Do not discard the primer — it is used three times in total.

4. Apply Mesh Tape Once the primer is dry, apply 100mm self-adhesive fibreglass mesh tape over all joints and around all edges. Pre-fold sections to wrap over edges neatly. Restick any lifting edges with a dab of glue if needed.

5. Apply Microcement — Coat 1 Mix and apply the first coat of microcement thinly ("grain thickness") over the primed surface and mesh tape. While still wet, lay the Fibreglass Mesh Roll across all horizontal and vertical surfaces wider than 100mm. Embed the mesh flat into the wet microcement using your trowel — no ripples. Allow to dry 4–6 hours. Do not apply on days over 25°C.

6. Sand Coat 1 Sand the surface flat using an orbital sander with dust extraction. Start at 80 grit, finish at 120 grit. It's fine to sand into the mesh slightly.

7. Re-prime (coat 2 of 3) Vacuum the surface, then apply a second coat of primer. Allow to dry fully.

8. Apply Microcement — Coat 2 Apply the second coat of microcement as thinly as possible (grain thickness). Allow to dry 4–6 hours, then sand with 80 and 120 grit.

9. Re-prime (coat 3 of 3) Vacuum the surface and apply the final coat of primer. Allow to dry fully.

10. Apply Microcement — Coat 3 Apply the third and final coat of microcement as thinly as possible. Allow to dry fully.

11. Final sand Sand progressively through 80 → 120 → 180 → 240 grit to achieve a smooth, polished finish.

12. Seal Apply Concrete Lab Sealer as per the sealer instructions. Minimum 3 coats recommended for outdoor use.

⏱ Do not wet the surface for 48 hours after sealing. Reapply sealer annually to maintain protection.

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