How to Do a Lime Wash on Terracotta Bricks on My Hearth

Maintain and protect the terracotta bricks in your hearth by giving it a limewash. Lime is made from burning calcium carbonate, which leaves behind calcium oxide. Historically it was used in mortar and in paints. During the housing boom after World War II, cement products replaced lime because lime takes longer to cure than cement. However, lime is considered eco-friendly and breathable because it does not trap in moisture. This makes limewash ideal for porous materials, such as terracotta brick. Allow the hearth to completely cure if it is newly constructed before starting this project.

Things You'll Need

• Wire brush
• Soft cloth
• Spray bottle
• Gloves, old clothes and goggles
• 25 lb. bag of hydrated lime
• 15.5 gallons water
• Large trough
• Electric paddle stirrer
• Drill
• Limewash brush

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Instructions

1. • 1

     Brush the terracotta bricks in your hearth with a wire brush to prepare the surface for the limewash. Smooth surfaces, especially terracotta, need this important step so the lime can adhere to the material. A wire brush also removes any debris.

   • 2

     Wipe the brushed terracotta bricks with a soft cloth to remove any dust or particles. Spray the bricks with water using a misting spray bottle to wet the surface. A slightly damp surface is ideal for the lime wash.

   • 3

     Wear gloves, old clothing and goggles before mixing the limewash. It is highly corrosive to skin. Mix together a 25-lb. bag of hydrated lime and 15.5 gallons of water in a large trough using an electric paddle stirrer. These can be attached to regular drills. Mix the limewash until the lime is suspended in the water.

   • 4

     Dip a limewash brush into the mixture and apply a thin layer onto the bricks in even up, down and diagonal strokes. If you cannot find a limewash brush, use a 2-inch wide soft bristled brush for the job. The limewash appears translucent and turns opaque as it dries.

   • 5

     Brush on five more thin coats of the limewash. Wait approximately 30 minutes or until the limewash coat looks opaque before adding the next coat.