We have to give time frame(total duration) for one project having 2 basement having built up area 6700 sqm each and and 3 floors of built up area 7000 sqm each.It will used for office purpose, with all necessary landscape and MEP works. Total building lenth is about 180m with C shape.How much total time required to constuct this building. My accessment is 18 month. Is it OK for the prelimanary reports?