Abstract: A resilient plug for closing and sealing the opening formed in a concrete wall by the removal of the tie rod used to support the walls forms. The elastic plug is formed with a tapered socket and has a smooth outer surface, including a tapered leading end and a main body section having a larger diameter than the hole in the concrete and extending from the leading end. The plug is engaged in a tie rod hole by inserting a rod into the socket and pushing the plug into the tie rod hole. This causes an elongation of the plug, reducing its diameter and facilitating its insertion into the tie rod hole. However, when the force applied to the plug during insertion is removed the plug expands radially, forming a tight seal with the wall of the tie rod hole.