Can You Microcement Over Plasterboard? (And What About Moisture-Resistant Plasterboard in Showers?)

One of the most common questions we hear is: can I apply microcement directly over plasterboard? The short answer is yes — but there are some important details to get right if you want a flawless, long-lasting finish.

Microcement Over Bare Plasterboard

Plasterboard is perfectly suitable as a substrate for microcement, but you’ll need to pay special attention to two things:

• Absorbency – Bare plasterboard is more absorbent than plastered or sealed surfaces. That means it requires considerably more priming to prevent the substrate from sucking the moisture out of the microcement too quickly. Skipping this step can cause uneven drying, weak adhesion, or patchy colour.
• Joints & Surface Prep – Every joint, screw hole, and surface irregularity must be completely level and smooth before applying microcement. Any bumps or ridges will telegraph through the thin layers. One option is to skim plaster over the plasterboard first. This gives you a seamless, uniform surface, making microcement application easier and the final finish more consistent.

Moisture-Resistant Plasterboard in Shower Enclosures

Another popular question: is moisture-resistant (MR) plasterboard a good substrate for microcement in showers?

The answer: not ideal.

Moisture-resistant plasterboard is commonly used as a backing board for tiles. While it’s treated to withstand humidity, it’s still not particularly strong when it comes to impact. If you microcement directly over MR board, the surface might look robust, but a good hard knock could still punch through the board behind it.

For showers and wet areas, the gold standard is cement board. Unlike plasterboard, cement board is solid, water-stable, and far better suited to carrying a tough microcement finish.

Don’t Forget Tanking

Whichever substrate you use in a shower, every surface must be properly tanked before applying microcement. This creates a waterproof barrier and ensures the system performs long-term.

*AI generated image

You can find our full bathroom wall application guide (including tanking instructions) here:
👉 Microcement Bathroom Wall Application Instructions

Key Takeaways

• ✅ You can apply microcement over plasterboard — but prime it heavily and make sure joints are perfectly smooth.
• 🎨 For the best finish, skim plastering first is recommended.
• 🚿 Avoid moisture-resistant plasterboard in showers; choose cement board instead.
• 💧 Always apply a tanking liquid in wet zones before finishing with microcement.

Closing Thoughts

Microcement can transform walls, bathrooms, and showers into seamless, modern surfaces — but choosing the right substrate is key to a long-lasting finish. Whether you’re working with plasterboard, cement board, or planning a full bathroom renovation, following the right prep steps will make all the difference.

👉 Explore our microcement guides and products to get started with confidence, or reach out to the Concrete Lab team for expert advice on your project.