What is the purpose of drilling two holes in a void when applying grout?

The purpose of drilling two holes in a void when applying grout is primarily to expel air and ensure that the void is properly filled with grout. When grouting, it's crucial to eliminate any air pockets that may form, as these pockets can compromise the integrity and effectiveness of the grouting process. Air trapped in the void can lead to incomplete filling, reducing the strength and stability of the bond created by the grout. By drilling holes, workers can facilitate the flow of grout and ensure that it fills the entire space without air entrapment, leading to a more effective and durable application.

This approach not only improves the bonding of the grout to the surfaces within the void but also maximizes the performance of the overall grouting operation, ensuring completed structures can support loads as intended.