Foundation walls are the vertical structures that support a building's weight and transfer it to the ground. They are typically made of materials like concrete, brick, or stone and are designed to withstand various forces, including soil pressure and water. Properly constructed foundation walls help prevent issues like settling or shifting, ensuring the stability of the entire structure. These walls also play a crucial role in protecting the building from moisture and pests. They are often built below ground level, creating a barrier against water infiltration and termites. Insulation may be added to foundation walls to improve energy efficiency and maintain comfortable indoor temperatures.