The standard house comes complete with a concrete slab for the patio. Most people never do anything beyond sweeping the slab or the occasional power wash to remove barbeque, beverage, and pet stains.

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 with ...

Question: My wife and I have an outdoor patio built 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 ...