The value of building permits fell by a much-larger-than expected 10.8% in May from April, slipping to $6 billion, Statistics Canada reported Tuesday.
Analysts polled by Bloomberg had called for a 2% month-over-month drop.
The federal agency blamed decreases in both the residential and non-residential sectors for the decline.
The decline follows two previous monthly increases and still leaves the value of building permits 13.9% higher than in May 2009.
The value of residential permits fell 5.3% to $3.7 billion as a result of a decline in the single-family component, Statistics Canada said, while the value of non-residential permits fell 18.3% to $2.3 billion.
The industrial component, however, rose 47.1% to $644 million, the fifth consecutive monthly increase.