Which joint finish provides the greatest moisture resistance?

• A. Butt Joint
• B. Raked Joint
• C. Tooled Joint
• D. Beaded Joint

Answer: (C)

Moisture resistance in mortar joints comes from a profile that minimizes voids and capillary flow. A tooled joint creates a concave, dense surface by pressing the mortar with a jointer while it’s still plastic. That compacted shape seals small gaps and reduces porosity, so water is less likely to wick into the joint and is more likely to shed off the surface. In contrast, raked joints leave the joint open and exposed, providing channels for water to penetrate; beaded joints have a protruding bulb that can trap moisture and trap water at the surface; butt joints have less mortar contact and rougher faces, offering more pathways for moisture to enter. So the concave, tooled joint offers the best moisture resistance.