A mounting system for mounting an external structure, such as a deck, with a building includes an anchor frame that couples with structural elements of the building and a bracket that couples with both the external structure and the anchor frame for securement. The anchor frame includes a plate element configured for mounting against a board of a building and anchor elements extending from the plate element and configured for mounting against a second board of a building. The bracket has a first face portion configured for coupling with the anchor frame and a second face portion spaced from the first face portion and configured for mounting with an external structure.