Well first of all, the main thing you need to know is that I am living in a small flat, only approximate 40 square meter.
Well, for the IELTS Speaking task 1, you need to have a more friendly and cool approach. Your score would depend on how well you set up the interaction between you and the examiner.
So, have a more simple tone;STEP I;Answer the question direct;
Well, I live in a flat.STEP 2:
Now expand on your answer introducing more details ;
It is a small flat which is about 40 square meter in floor area. It has one bedroom, living room and a kitchen.
Though it's small in size, I like it's location and the design.
The above would be enough for you to handle that 4 to 5 mins allowed for this task :)