Investors interested in stocks from the Building Products - Miscellaneous sector have probably already heard of Owens Corning (OC) and Armstrong World Industries (AWI). But which of these two companies is the best option for those looking for undervalued stocks? Let's take a closer look.We have found that the best way to discover great value opportunities is to pair a strong Zacks Rank with a great grade in the Value category of our Style Scores system. The Zacks Rank favors stocks with strong earnings estimate revision trends, and our Style Scores highlight companies with specific traits.Right now, Owens Corning is sporting a Zacks Rank of #2 (Buy), while Armstrong World Industries has a Zacks Rank of #4 (Sell). This system places an emphasis on companies that have seen positive earnings estimate revisions, so investors should feel comfortable knowing that OC is likely seeing its earnings outlook improve to a greater extent. However, value investors will care about much more than just this.Value investors also try to analyze a wide range of traditional figures and metrics to help determine whether a company is undervalued at its current share price levels.The Style Score Value grade factors in a variety of key fundamental metrics, including the popular P/E ratio, P/S ratio, earnings yield, cash flow per share, and a number of other key stats that are commonly used by value investors.OC currently has a forward P/E ratio of 14.47, while AWI has a forward P/E of 20.78. We also note that OC has a PEG ratio of 1.30. This metric is used similarly to the famous P/E ratio, but the PEG ratio also takes into account the stock's expected earnings growth rate. AWI currently has a PEG ratio of 5.65.Another notable valuation metric for OC is its P/B ratio of 2.28. Investors use the P/B ratio to look at a stock's market value versus its book value, which is defined as total assets minus total liabilities. By comparison, AWI has a P/B of 8.82.Based on these metrics and many more, OC holds a Value grade of A, while AWI has a Value grade of C.OC has seen stronger estimate revision activity and sports more attractive valuation metrics than AWI, so it seems like value investors will conclude that OC is the superior option right now.Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Owens Corning Inc (OC): Get Free Report Armstrong World Industries, Inc. (AWI): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research