The agency says the decline, which followed a 21.4 per cent increase in July, was the result of lower construction intentions in both non-residential and residential sectors.
It says with this decline, the trend in the value of building permits has become relatively flat since the beginning of 2013.
With the exception of British Columbia and Newfoundland and Labrador, every province registered declines in August with Ontario, Alberta and Quebec posting the largest drops.
In the non-residential sector, the total value of building permits fell 37.9 per cent to $2.4 billion in August, its lowest level since February 2013.
The value of permits in the residential sector decreased 5.4 per cent to $3.9 billion in August.
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