In a foundation assembly, a moisture barrier is placed on a footing and a foundation wall is on the moisture barrier. The moisture barrier thus isolates the foundation wall from the footing. The footing defines a keyway. The moisture barrier comprises a waterproof layer, a bottom layer attached to bottom side of the waterproof layer, and a top layer attached to the top side of the waterproof layer. The waterproof layer blocks passage of water therethrough. The bottom layer is for attaching the moisture barrier to the footing, and comprises a material that attracts water and binds to cement. The moisture barrier comprises a keyway portion sufficiently flexible and configured to fit the keyway in the footing. When the keyway portion fits to the keyway on the footing, it defines a secondary keyway for receiving a key portion of the foundation wall.