HDB写的很清楚要等30个月啊Ex-Owner of an EC Are you, your spouse or any of the essential occupiers listed in the application an ex-owner of an Executive Condominium bought directly from the developer? If yes, you would need to meet a 5-year period from the date of taking possession of the earlier Executive Condominium. 30-Month Period In addition, you need to wait out a 30-month period from the effective date of disposal (i.e., date of legal completion of the sale of your Executive Condominium, evidenced by the Notice of Transfer or such other documentary evidence as HDB may require) of the Executive Condominium before you can apply to buy an HDB flat.