Around the world, countries are hosting rapidly accelerating aging populations, with many establishing and implementing building guidelines to ensure successful aging-in-place as a response. Universal design has been adopted as a general approach, with the endorsement of UNCRPD and WHO. Best practices have also been proposed in some nations to set an even higher standard to guide the industry. At the same time, the prevalence of dementia is increasing. Following the emergence of Evidence/Research-Based Design and Salutogenic Design, design for the elderly no longer comprises discrete considerations of mobility or sensory deficits, but incorporates a continuum of physical, mental, cognitive and psychosocial factors in one holistic approach. Such an approach will benefit people of all ages. For a vertical city like Hong Kong, it can be adapted to suit high rise living and mass ground movement of the densely distributed city network. (“Double Aging” refers to the phenomenon of simultaneous occurrence of an aging population and aging building stock, having profound impacts on society and urban living.)