Monique recently purchased a new house and plans to the basement into her dream wine cellar. To make her dream into reality, Monique contracts with SM Construction to perform the work. The contract specifiesthat the pipes for the cooling system will be installed inside the walls and be of Grade A specification. However, after SM Construction completed the project, it was discovered that Grade B pipe was used inadvertently. Grade A and B pipe are substantially similar, with Grade A pipe having a slightly longer service life. The project has been completed. Monique is not happy with the mixup and doesn't want to pay SM Construction.

Did SM Construction's actions constitute a breach under the contract? Please explain your answer.