Hi, I'm currently planning to add another bedroom in my old 3rm flat (old design) as I am thinking of having another child. I wanted to use my storeroom as another bedroom by knocking down the side of the wall then bulid a sliding door to act as a divider or wall. If possible, how about the ventilation of the new room? Anyone can give advise if you have done this before. Please dun ask me to upgrade as after caluation on upgrading a BTO flat, the amount of levy fees and interest make me totally forgo the idea of BTO. Thanks for reading.