The Architecture Billings Index switched gears in April, falling to 48.6 from a mark of 51.9 in March, according to the AIA Economics & Market Research Group.
The ABI reflects an approximate nine to 12 month lag in time between architecture billings and construction.
The significant decline to 48.6 shows a decrease in demand for design services, the research firm said.
Additionally, this is the lowest score since July 2012, any score above 50 indicates an increase in billings.
Meanwhile, the regional averages hit 52.6 in the South, 50.7 in the West, 49.4 in the Midwest and 48.2 in the Northeast.
Also dipping down, the new projects inquiry index hit 58.5, down from 60.1 the last month.
"Project approval delays are having an adverse effect on the design and construction industry, but again and again we are hearing that it is extremely difficult to obtain financing to move forward on real estate projects," said AIA chief economist Kermit Baker.
"There are other challenges that have prevented a broader recovery that we will examine in the coming months if this negative trajectory continues," he added. "However, given that inquiries for new projects continue to be strong, we’re hopeful that this is just a short-term dip."