How to get a Exposed Aggregate Finish on Concrete

Introduction

This tutorial will guide you through the process of achieving an exposed aggregate finish on concrete, inspired by David Odell's techniques. This finish not only enhances the aesthetic appeal of your concrete surfaces but also provides durability and slip resistance, making it ideal for outdoor settings like stepping stones or patios.

Step 1: Prepare Your Concrete Mix

• Select Your Materials: Use a mix ratio of 3:2:3 for aggregate, sand, and cement, respectively. This creates a rich mixture that bonds well with the aggregate.
• Mix Ingredients: Combine your dry ingredients thoroughly in a mixing container.
• Add Water Gradually: Slowly add water to achieve a workable consistency without making the mix too wet.

Step 2: Clean the Aggregate

• Prepare the Aggregate: If you are using bagged aggregate, puncture the bottom of the bag to create holes.
• Wash the Aggregate: Rinse the aggregate thoroughly with water until it runs clear to remove dirt or organic materials. This ensures a good bond with the cement.

Step 3: Pour and Float the Concrete

• Initial Pour: Pour the concrete mixture into your desired area, ensuring it is about half an inch lower than the final desired height.
• Hand Float the Surface: Use a hand float to smooth the surface and ensure an even layer.

Step 4: Seed the Surface with Aggregate

• Apply Aggregate: Immediately after floating, spread your clean aggregate evenly over the surface of the concrete.
• Cover Completely: Ensure that the entire surface is covered with aggregate; you should see little to no concrete visible.

Step 5: Embed the Aggregate

• Tamp the Aggregate: Use a jitterbug or a roller tamper to press the aggregate into the concrete. Do this within 20 minutes of applying the aggregate for best results.
• Watch for Cream Rise: This process will allow the cream (the fine cement paste) to rise and envelop the aggregate, creating a solid bond.

Step 6: Expose the Aggregate

• Wait for the Right Time: After about seven hours, and when the surface feels right to touch, it’s time to start the exposure.
• Use a Broom: Gently sweep the surface with a large horsehair broom to loosen the top layer of cement, allowing the aggregate to show through.
• Add Water: Lightly spray water on the surface to help with the exposure process.

Step 7: Final Touches

• Seal the Surface: After exposing the aggregate, consider applying a wet look sealer to enhance the appearance and protect the surface.
• Allow to Cure: Follow the manufacturer’s recommendations for curing times and conditions.

Conclusion

Following these steps will help you create a beautiful exposed aggregate finish that is both functional and visually appealing. Remember to maintain cleanliness throughout the process to ensure the best results. Once completed, you can enjoy your new concrete finish or use the technique to create multiple stepping stones for your yard. For more tutorials, consider subscribing to video channels that offer similar content.