A ground moisture barrier, also known as a vapor barrier, prevents moisture from seeping into the building from the ground. It protects against issues like rising damp, mold growth, and structural damage. Typically made of materials like polyethylene or bitumen, it is installed under the foundation to block moisture and maintain a drier, healthier indoor environment. It also provides insulation benefits, contributing to energy efficiency and reducing heating and cooling costs. Installing a ground moisture barrier is crucial for protecting buildings and ensuring long-term durability.