Top home improvement retailer Home Depot Inc posted a 27 percent drop in quarterly profit and forecast a steeper fall in full-year earnings on Tuesday as the slumping U.S. housing market cut into sales.

The company also said that although it was still committed to a $22.5 billion stock buyback plan announced in June, it was taking a more cautious stance on the timing of its completion.

Earnings fell to $1.1 billion, or 60 cents a share, in the third quarter ended on October 28 from $1.5 billion, or 73 cents a share, a year earlier.

Sales declined 3.5 percent to $18.96 billion. Sales at stores open at least a year fell 6.2 percent.

Home Depot said earnings per share from continuing operations could drop as much as 11 percent for the fiscal year, compared with the 7 percent to 9 percent decline it had forecast in September, as it expects the housing market softness to continue through the period.

The company said its outlook was based on a 52-week year but added that the period had 53 weeks. The extra week should add about 5 cents per share to earnings.

Home Depot also said it was taking a guarded stance on completing its planned $22.5 billion share buyback.

Earlier this year, the company bought back about 290 million common shares for $10.7 billion, partly financed with proceeds from the sale of the Home Depot Supply unit. That buyback was part of the bigger $22.5 billion repurchase announced over the summer.

(Reporting by Karen Jacobs; Editing by Lisa Von Ahn)