average cost of a new garage
1 According to author Stu Silverman the average cost of adding a garage begins at roughly $7,500, and for a two-car garage the average costs will go much higher.2  This sort of structure will average at $27,040. 3  The resale value of this update would hold at $21,635, or a nearly 81% return on investment.or the garage addition, the typical costs include: 1  According to author Stu Silverman the average cost of adding a garage begins at roughly $7,500, and for a two-car garage the average costs will go much higher. 2  The above figures place the garage addition at $40 per square foo t.