The commodity-sensitive loonie lost 0.2 of a cent to 96.96 cents US as Statistics Canada said municipalities issued building permits worth $6.3 billion in August, down 21.2 per cent from July.
The decline followed a 21.4 per cent jump in July, but economists had expected a drop of only 15 per cent for August.
The loonie was also lower as worries about the economic fallout of the U.S. government shutdown and reaching the debt ceiling pushed down crude oil prices.
The bitter argument over the U.S. budget stretched into its second week as the country looked ahead to an Oct. 17 deadline for raising the debt limit.
The November crude contract on the New York Mercantile Exchange fell 81 cents to US$103.03 a barrel.
December copper was unchanged at US$3.30 a pound while investors looking for safety pushed December gold bullion ahead $15.20 to US$1,325.10 an ounce.