Water Marks Caused by Pools of Water
The microcement that we recommended bathroom, wet room and shower areas is completely waterproof.
However, water left sitting for long periods can leave a watermark, because the sealers are breathable and not meant to stay submerged for hours.
Once dry, the mark should fade, but if the water pooling becomes a persistent problem, here’s how to fix it.
The microcement that we recommend for bathrooms, wet rooms & showers is completely waterproof, but if water is left sitting on the surface for prolonged time periods, it can start to leave a watermark over time.
This is because there is an element of breathability to the sealers, they are not intended to be fully submersed for several hours.
When the surface is dried out, the water mark should disappear.
Identify Why the Water is Sitting on the Surface?
The first step is to identify why the water is sitting on the surface.
Temporary Pool of Water
If it is a temporary issue, like a leak, that has now been fixed, you should be able to clean up the water & let it dry out. Unless the sitting water is likely to return regularly, this should resolve the issue.
Regular Pool of Water
If the water is regularly pooling in a particular area of a shower or wet room, it’s most likely because the floor is angled incorrectly for water to drain towards the shower waste.
Overtime, the sitting water will seep through the sealer and may result in a water stain.
There are 2 approaches that you can try to resolve this issue:
Option 1: Reseal the Surface
It may be that there isn’t enough sealer on the surface, which is why water is getting to & sitting on the microcement. To resolve, reseal the surface.
Option 2: Repair the Floor
Check the tray & surrounding floor with a spirit level to identify what is causing the water to pool. The pool of water itself will give you a big clue here, the floor will most likely need to have a steeper gradient towards the waste where the water is sitting.
Sand back the area to give the surface a key. Then trowel on a cement repair mortar to increase the gradient in this area. You may need to use a primer to ensure a good bond with the polyurethane sealer. Check with the manufacturer of the cement repair mortar for more information on required primer. Feather product so it blends seamlessly into the microcement surface without leaving a ridge.
Once the cement repair mortar is fully dry (maximum 5% moisture content), you can recoat the microcement.
Recoat the Area with Microcement
Once the area is clean and dry, apply a coat of Primer 100 over the entire area, including the repair mortar, followed by 2 additional top coats and then sealers. See the relevant product installation guide for full application instructions for each product.
You’ll probably notice that the first coat of microcement appears grainy and may drag, this is why we recommend a second top coat, which should go on a lot more smoothly.
Avoid Patch Repairs
Microcement is notoriously difficult to patch, even when using the same product from the same tub, you may well see a colour difference between the original floor & the patch.
You’ll most likely get a much cleaner result by completing the recoat across entire surfaces e.g. the entire floor up to the external edgesor working up to a threshold e.g. the shower area up to the point of entry into the shower.