Yes, it is generally recommended to have a plywood substructure or substrate under a marble countertop. Plywood provides a stable and even base for the heavy weight of the marble slab and helps to distribute the load more evenly across the cabinets or support structure beneath.
Here are a few reasons why plywood is commonly used as a substructure for marble countertops:
Support and Stability: Marble is a dense and heavy material, so a sturdy and stable support is required to prevent sagging or cracking. Plywood provides a solid foundation that helps to distribute the weight of the marble and reduces the risk of structural issues over time.
Moisture Resistance: Plywood that is properly sealed or treated with moisture-resistant coatings helps to protect the countertop from potential moisture damage. It acts as a barrier, preventing water or other liquids from seeping into the substrate and potentially causing warping or other issues.
Flexibility and Ease of Installation: Plywood is a versatile material that can be easily cut and shaped to fit the countertop's dimensions. It allows for flexibility during the installation process, ensuring a precise and secure fit for the marble slab.
When installing a marble countertop, it's crucial to follow the manufacturer's guidelines and consult with a professional installer to determine the specific requirements for your particular project. They will be able to assess the structural needs and recommend the appropriate substructure materials based on factors such as the thickness and size of the marble slab, the underlying cabinets or support structure, and the overall design of the countertop.
By providing proper support with a plywood substructure, you can help ensure the longevity and integrity of your marble countertop installation.