Acrylic Water Repellent Sealers Concrete Buildings July 28, 2021 by Administrator City Hall Building – London – Wind driven rain was penetrating exterior block. 460 WATER REPELLENT SEALER was applied to all exterior block effectively stopping moisture penetration.Dundas, ON Apartment Building – Rain and moisture were penetrating exterior block and brick. 460 WATER REPELLENT SEALER was applied to all exterior block effectively stopping moisture penetration.