We propose a method to detect shifts in housing price expectations by observing excess capacity. Anticipated future price hikes lead to increased current supply, resulting in temporary vacancies. Using a structural vector autoregression with sign restrictions, we analyze the impact of these expectations on the U.S. housing market. Our findings indicate that price expectation shocks primarily drove the 1996–2006 boom, especially in the Sand States. At the boom's peak, these shocks stemmed from unrealistic growth expectations, which reversed during the bust.