Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares building product provider of Armstrong World Industries, (NYSE:AWI) fell 10% today after the company reported earnings.

So what: Revenue was up 7.9% from a year ago to $661.3 million and net income rose 17.4% to $10.8 million, or $0.20 per share. Revenue was ahead of expectations, but adjusted earnings of $0.32 per share (after pulling out one-time items) were still $0.08 below estimates.

Now what: Investors also weren't thrilled with 2014 guidance for earnings of $2.55-$2.80 per share, although that's a big jump from $2.04 per share in 2013. Expectations look to have just gotten ahead of themselves; with continued growth, I think Armstrong is in good shape. Shares trade at just 19 times the top end of 2014 estimates, which isn't cheap but is a reasonable price for a company in a growing space in the construction industry.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.