Hemihydrate screeds, also known as calcium sulphate screeds or gypsum screeds, have different properties compared to traditional cement-based screeds. They have a higher moisture content and are more susceptible to moisture movement.
When tiling, it’s essential to have a stable and dry surface to ensure proper adhesion and prevent tile movement or cracking. Hemihydrate screeds can have higher moisture levels, which can lead to issues such as adhesive failure, tile delamination, and mould growth.
To tile onto a hemihydrate screed, it is generally recommended to apply a suitable primer. This helps to create a more suitable substrate for tiling. Consult with a professional tiler or follow the guidelines from Ardex Ireland to determine the best approach for your specific situation.
It’s important to ensure that the screed is fully cured, moisture levels are within acceptable limits, and any necessary primers and mechanical preparation is carried out before tiling to achieve a successful and long-lasting tile installation.