This building is designed to store a key resource of the game: the building materials needed for the construction and improvement of base buildings and further defensive structures. The game begins with a first level Materials Depot. Upgrade it to increase the amount of building resources you can store, and the rate that they replenish.
Over the war, the Soviets suffered a severe lack of various resources. The crisis eased with the supply hundreds of thousands of tons of materials under the Lend-Lease program, but the total aid from the Lend-Lease program amounted to only 4% of Soviet funds spent on the war. In December 1941, Soviet production finally regained its footing, and by mid-1942 the faltering military industry managed not only to recover, but to exceed and excel.