It didn’t exist. No Seriously. There was no boom in housing construction.
The constructing in US housing was exactly what was needed to maintain the housing-population ratio in the face of increased population growth. You cannot have an “unsustainable boom” without oversupply. If you are building exactly the amount that you need, and prices are rising anyway, it is the very definition of a sustainable boom.
Its true that housing prices rose and then fell, but they fell exactly the amount that you would expect when there was a peak to trough fall in national income. What does that prove except when people are poorer they will pay less for housing. A change in prices is never the cause of anything, it is always the result of something. The correct way to reason is not “why did an asset crash cause a recession” it is “what caused asset prices to crash”.
Aggregate demand is the only story. The world’s central banks let it fall off a cliff in 2008, when they could have prevented it, purely because they were focused on inflation and forgot about nominal income. They assumed that because, historically, inflation and NGDP had been pretty well correlated, that controlling inflation would automatically control aggregate demand at a healthy level. They, in fact, made exactly the mistake that others accuse banks of having made – that they showed too much trust in their theory and didn’t have enough prudence. If the central banks had been watching aggregate demand, this recession could have been a non event.