Click on graph for larger image in new window.This graph shows housing starts (both total and single unit) and unemployment (inverted).
You can see both the correlaton and the lag. The lag is usually about 12 to 18 months, with peak correlation at a lag of 16 months for single unit starts. The 2001 recession was a business investment led recession, and the pattern didn't hold.
This suggests unemployment might peak in Spring 2010.