Shares of

Lowe's

(LOW) - Get Report

were dropping in preopen trading after the home improvement retailer this morning said it expects same-store sales to fall short of expectations in the third quarter. Lately the shares were quoted as $39.50 on

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, down from yesterday's close at $42.13.

The company said it is comfortable with the

First Call/Thomson Financial

earnings consensus estimate for 53 cents a share. Lowe's blamed weakening lumber and building materials prices (yup, if you're a consumer walking the aisles there, you're going to be paying less) and a change in merchandise in some of its chain stores.