Thank you for posting your feedback. We are sorry to see your low star review on DAP Concrete and Mortar Filler and Sealant. Thank you for posting your feedback about DAP CONCRETE & MORTAR FILLER & SEALANT. Because this sealant is an acrylic-latex (water-based) formula, its sole drying mechanism is the loss of water (evaporation). The most common causes for slow performance development/poor water resistance is generally related to one or a combination of factors such as: damp application surfaces, high humidity and/or deep/thick application. Because you did not provide enough details regarding your attempted application (surface preparation, surface conditions, humidity, joint dimensions, application technique), we are not able to provide you with a more detailed response in this format. Should you wish to provide this information, so we can better address your concerns, please feel free to contact DAP’s Technical Customer Service Department at 888-327-8477.