Cement output fell 4.7 percent year on year to 1.7 billion tons in the first three quarters, in contrast to the 3-percent gain seen during the same period last year, the National Development and Reform Commission (NDRC) said on its website.
Output of flat glass dropped 7.5 percent, compared with the 3.8 percent rise in the same period last year.
Meanwhile, compared with a month earlier, the factory price of cement edged down 0.8 percent in September.
The data came as the property sector, a major consumer of cement and flat glass, is plagued by a nationwide supply glut, especially in third-tier cities.
Housing investment rose 2.6 percent year on year from January to September, down 0.9 percentage point from the first eight months and down 2 percentage points from the first half of the year. New home construction dropped 12.6 percent year on year in the period.
Slower investment and construction underscored a major home glut in lower-tier Chinese cities, and analysts predict it will take several years before existing homes find buyers.