Hard Worker Integral Waterproofing is an excellent product for water resistance in concrete. Just up to 200 ml* per 50 kg of cement can reduce water permeability substantially - making the concrete denser and protected from the inside. By becoming part of the structure, HW101 strengthens concrete from within. It does all the above without changing the concreting process. Recommended for Foundations, Columns, Beams and Roof Slabs. HW101 has a unique property that strengthens the concrete by 10%.