Yes, you can install a backsplash directly onto drywall, provided the wall is properly prepped, clean, and dry. For best results, especially in kitchen areas, your walls should be made of moisture-resistant drywall, often called green board. If your current wall isn't moisture-resistant, it's recommended to replace it before installing the backsplash. For even greater protection against water damage, you can remove the existing drywall and install a tile backer board or cement board instead. While properly installed standard drywall is typically strong enough to support a backsplash, some local building codes may require water-resistant materials in kitchen areas, so it's a good idea to check.

How long painted tiles last ultimately comes down to the quality of the paint job and how much wear and tear the tiles get. It’s possible the paint job will only last about six months if the tiles are in a high-traffic area and they weren’t properly cleaned, sanded, and primed prior to painting and sealing. Well-painted tiles in a low-traffic area should last at least a year.

Whether you use a brush or roller depends on the size, shape, and amount of tiles. Rollers are easier to maneuver over large areas and can apply a more even coat of paint in a shorter time frame with no visible brushstrokes. Brushes are best for precision work, particularly in very small areas. If you don't want visible brushstrokes on your painted tiles, you can paint details with small foam brushes instead of bristled paint brushes.

Yes, cracked tiles allow water to seep through the substrate or subfloor, leading to mold and mildew growth. It can also cause severe structural damage. At the very least, water damage can cause your tile to lift from the substrate, meaning one cracked tile can lead to several cracked tiles. It’s a good idea to waterproof tile in areas with direct water exposure or lots of moisture.