Water Marks in Microdur & Other Traditional Microcements
Traditional microcements, like Microdur, when mixed with water, are very porous and rely on the sealer to make them waterproof.
This is why we only ever recommend them for use by microcement professionals, who understand the risk and are willing to accept them.
This guide will tell you everything you need to know about water marks and how to deal with them.
Why are there Water Marks on my Microcement?
Historically, porous micocements like Microdur, mixed with water, were the only option available to installers. And it was the Hydroprimer that soaked into the surface to saturate it, followed by AquaMax or MaxiPur, adding a hard surface protection, that made the system waterproof.
This system works well, but only if there is sufficient sealer across the entire area. Even a single pinhole, caused by an air bubble, in the microcement, or the sealer, can allow water to penetrate through to the microcement & cause a water mark.
Thankfully, this isn’t a problem with Microne, Microne Plus and MicroPool, so we highly recommend choosing these for wet areas, if you’re installng microcement for the first time or are a DIYer.
How Can I Get Rid of Water Marks in my Microcement Surface?
If insufficient sealer has been applied, you’ll probably discover this quite quickly after install. Most likely, when it is wet for the first time.
Usually, the surface will darken where water has penetrated through to the microcement, but dry out once the area has been left to dry.
It’s important that you act quickly to avoid the water mark becoming a permanent stain.
Let the surface dry out completely. You need to be sure that it is completely dry and there are no visible water marks before applying more sealer. If you apply the sealer too soon, it could trap moisture under the surface.
If the water mark doesn’t disappear, then give the area a gentle sand with a 220 grit sanding disc, if this doesn’t sand it back enough, then you can try a 120 grit. This will remove some of the sealer & allow some air to get to the surface. Take care not to sand back as far as the microcement as this could affect the appearance.
Once the area is clean, dry, the water marks have disappeared & you are happy with the appearance, then you can apply additional sealer coats.
Apply 1 or 2 coats of AquaMax Pro or MaxiPur over the entire area according to the installation guide.
What if the Water Marks Don’t Dry Out?
If the water marks are left for some time without treatment, they can become more permanent and may not dry out, this is why its important to act quickly.
If this happens, the only option is to prime then recoat the surface with microcement top coats, followed by sealers.