* Value of all permits issued in August falls 21.2 pct from July
* Nonresidential permits down 37.9 percent
* Residential permits decline 5.4 percent
OTTAWA, Oct 7 (Reuters) - Canada's construction sector showed more weakness than expected in August, with a sharp decrease in plans for commercial and institutional buildings while housing showed a more modest decline, according to Statistics Canada data on Monday.
The seasonally adjusted value of building permits issued in August fell 21.2 percent to C$6.34 billion ($6.16 billion) after jumping 21.4 percent in July to a record high, Statscan's revised numbers showed. Analysts in a Reuters survey had forecast a 7.4 percent decrease in August.
"With this decline, the trend in the value of building permits has become relatively flat since the beginning of 2013," Statscan said.
The report supported Finance Minister Jim Flaherty's comments last month that the housing sector is "calming" after a period of worry that a post-recession housing boom would turn into a bubble. Permits for housing fell 5.4 percent in August following a 4.2 percent rise in July, and were down 7.1 percent from a year earlier.
Permits for multi-family dwellings fell 8.3 percent and those for single-family units slipped 3 percent.
The value of nonresidential building permits tumbled by 37.9 percent, nearly erasing the 47.3 percent gain in the previous month. The commercial component was down 45.8 percent and plans for institutional buildings also fell 36.7 percent. The value of permits in the industrial component fell just 1.2 percent.