All Examples Above are Based on 15x28 Addition on a current 1100 Sq Foot home Current value of the home is $477,000 Mortgage Owing $385,000 current payment is $1927.40 Mortgage After Addition 385+185=570 new mortgage after addition New mortgage payment $2845.84 Mortgage Amount for Just New Addition Rate 3.5% OAC 25 Year Amortization 5 year fixed term