For the fourth straight month, construction spending on single family homes dropped in July as investors fear a serious slump in the housing market has begun.

Single family home construction spending fell by 4% according to the Commerce Department data. Spending increased only 2.9% over the previous year.

The released numbers were not adjusted for inflation, so the declines in construction activity are likely much steeper.

Materials and construction components prices rose 0.3% over the previous month according to the Producer Price Index from the Labor Department. That is a rise of 14.3% over a year prior. Private sector construction services were up 5.4% month over month, and prices are up 25.3% for the year.

To summarize, inflation-adjusted spending on single-family home-construction has dropped by double digits, and may be down as much as 25%.

On August 16th, the Commerce Department reported housing starts have fallen every month since February. During that decline, the total drop has been 24.5%. In August, starts dropped 9.6% over the prior month.

Overall residential construction was dragged down by the drop in spending 0.4%. Total Construction spending was down 0.4%, compared to the revised 0.5% drop in June.

Non-residential construction private spending, which operates under longer term contracts, and thus often shows a lag in response to changing economic conditions, increased 0.4%.

Private non-residential spending rose among most categories, with the exception of healthcare, sewage, and water.

Total public construction spending was up 1.5%.