ConstructConnect announced today that the September 2025 volume of Total Nonresidential Construction Starts—the combined sum of Nonresidential Building and Civil Construction — was $45.7 billion. This represents a $4.9 billion decrease from August’s revised reading of $50.6 billion.
According to ConstructConnect Chief Economist Michael Guckes, the September figure marks the third consecutive monthly decline since the record high of $85.9 billion was set in June. The weakness in spending during August and September was widespread, affecting most construction categories.
Total US Construction Starts were $66.7 billion through September, a 21.7 percent decline from a year ago, and a 5.6 percent drop from August. Image: ConstructConnect Construction Economy Snapshot
Guckes reported that the slowdown in late Q3 has tempered the strong growth seen earlier in the year. Year-to-date (YTD), Civil construction growth decelerated to 3% through September, a notable drop from the 7.1% growth recorded at the end of the second quarter.
Similarly, YTD growth in Nonresidential Building spending fell from 18.8% at the end of Q2 to 13.4% through the end of Q3. Guckes said, “This decline would have been far more severe without a $11 billion surge in data center starts.”
The September 2025 volume of Total Nonresidential Construction Starts—the combined sum of Nonresidential Building and Civil Construction — was $45.7 billion. This represents a $4.9 billion decrease from August’s revised reading of $50.6 billion. Image: ConstructConnect Construction Economy Snapshot
An $11.1 billion surge in data center starts during the third quarter proved to be a critical bright spot for the Nonresidential Building sector.
This represents a 101% increase in quarter-over-quarter (QoQ) spending for the category. Guckes said that the performance of data centers helped offset significant weakness elsewhere.
Institutional spending, in contrast, performed far worse, experiencing a 32% QoQ decline. This drop was led by substantially lower spending on essential projects like Schools and Hospitals.
U.S. Nonresidential Building and Civil Construction Starts are shown on a graph from the Construction Economy Snapshot. September 2025 Total Nonresidential Construction Starts (the combined sum of Nonresidential Building and Civil Construction) fell to $45.7 billion, down $4.9 billion from August. Image: ConstructConnect
Within nonresidential construction, performance trends through September have been highly divergent across large-dollar categories, Guckes reported.
The industrial sector leads the growth, with Manufacturing starts surging 82%.
Following this trend, the Commercial sector was driven by an exceptional 38% rise in Office construction, which includes the booming data centers.
Public infrastructure spending on Airports rounds out the top performers, with project starts increasing by a significant 30% year-to-date.
Michael Guckes, Chief Economist, ConstructConnect
In contrast, several key categories have experienced considerable declines in spending. Power Infrastructure plummeted by 57% year-to-date. Institutional spending on Prisons has also fallen sharply, recording a 45% contraction.
The hospitality sector continues to underperform as well, with Hotel and Motel construction starts declining by 21%.
The slowdown was particularly sharp in Civil construction, which contracted by nearly 30% on a QoQ basis. Deep quarterly declines in Power Infrastructure, Dams, Canals, and Marine Work, as well as Airports, all contributed to this significant deceleration.
While nonresidential growth has cooled, the contraction in the residential sector has accelerated. The overall YTD decline in residential construction worsened from 5.4% at the end of Q2 to 8.8% through Q3.
This erosion was primarily driven by “a weakening in Multifamily starts activity”, according to Guckes. After increasing by 5% through the first half of the year—its best reading in nearly two years—weak third-quarter activity caused Multifamily spending to reverse course, ending Q3 with a 6.1% YTD contraction.
Meanwhile, Single-family activity was largely unchanged, with the YTD contraction easing slightly from 11.1% in Q2 to 10.3% through September.
Read the Construction Economy Snapshot for more details on construction labor, trends, and regional analysis.
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