Hi Master Lee: Thank you so much for your kind response. Because the New Year is coming and I needed an answer urgently, I also posted this same question to 2 other websites and both advised similar reasonings. (please see below) I'm very confused and concerned as u can see different periods will affect the way I live and place remedies for the flat. Is there any text or source u can help refer me to for more understanding. I thank you again for your advice. ------------------- Reply # 1 we measure the construction cycle of the building from when the roof seals off the heavenly qi from flowing down into a building. Therefore, the only way a building can change its period is for its roof to be removed. The way I understand it, is that if more than half of the roof has been removed for at least seventy-two hours, and the foundation is exposed, then the heavenly qi can again spiral down on to the earth. If a new roof is then placed on the building, the new period for the building is the current period. In the case of the building you are describing, since the roof was not replaced, the period would not be changed. Reply # 2 The building belongs to period 6 as the authorities selling the building made sale transactions with people on Feb 1st 1984, it means the roof was already done before 1984 which is 6th period. So the house has stars of 6th period. It is the roof that matters more.