What is it?
Stopgap 1100 Gypsum is a self-levelling, calcium sulphate-based levelling compound, which is specially designed for use over calcium sulphate (e.g. anhydrite) screeds.
Where is it used?
It should be used over dry, suitably prepared and primed calcium sulphate screeds to create a smooth base ready for the installation of final floor coverings.
It can also be applied over other types of structurally sound subfloor, including sand/cement screeds, concrete, granolithic, terrazzo, epoxy and polyurethane resins, ceramic and quarry tiles and Stopgap waterproof surface membranes.
What’s different about it?
Unlike cement-based levelling compounds, Stopgap 1100 is similar in composition to calcium sulphate screeds, thereby ensuring maximum compatibility between the two.
Why it is needed:
Stopgap 1100 Gypsum is recommended for use over calcium sulphate screeds as the application of cement-based levelling compounds onto a calcium sulphate screed in damp environments can result in a reaction taking place that leads to the production of ettringite, a crystalline layer between the levelling compound and screed, which can result in bond failure.
Calcium sulphate-based levelling compounds optimise compatibility as they contract at a similar rate to the calcium sulphate screed underneath, limiting the amount of stress at the bond interface and minimising the risk of floor failure.