Civil Engineering (CE) is under Faculty of Engineering while Architecture is under Real Estate. Archi is 5-year program for undergraduate while CE is 4-year program towards Honors Degree.
Generally speaking you can choose some Archi modules to enrich yourself. And if your performance is good for those modules, you could talk to respective levturers to join thier other modules as "sit in" students.
However, you will never be granted Minor on Archi.
