Immigration is a driver of GDP and a solution to Australia’s declining birth rate, but as housing pressures mount, polls showing strong support for reduced intake could force the government into a debate on population growth," says Mike Secombe writing in the Saturday Paper."The high pace of immigration is not compatible with the level of housing supply that we have in this country. We're just not building enough homes to keep up with our population growth," AMP deputy chief economist Diana Mousina said late last year to the ABC.However some people think that this is not the main issue that’s causing our house prices and rentals woes. One of those is Tone Wheeler, regular A & D columnist, and a director at Environa Studio who is also a passionate advocate for environmental architecture. Tone has taught at universities for thirty years, served on boards and appeared regularly on television and radio.We recently sat down with him to talk about what he thinks is the reason behind our housing affordability crisis.