Dear Tim: My wife and I have an outdoor patio with colored precast concrete paving blocks. It doesn’t take long each year for black mold and mildew to start growing on it. We also have an issue ...

Slowly pour the concrete over the mold, stopping when you reach your desired thickness (¼-inch max). Let it dry for 21 days, and then sand until smooth. (F) Float: Your concrete canoe should ...

Watch Robot Arms Stretch Lycra To Make Strange and Unique Concrete Molds. The designers of the process say it will change pre-fab construction. By Sam Eifling Published: May 20, 2016 9:02 AM EDT.