Investors with an interest in Building Products - Concrete and Aggregates stocks have likely encountered both HeidelbergCement AG (HDELY Quick QuoteHDELY - Free Report) and Martin Marietta (MLM Quick QuoteMLM - Free Report) . But which of these two stocks is more attractive to value investors? We'll need to take a closer look to find out.

Everyone has their own methods for finding great value opportunities, but our model includes pairing an impressive grade in the Value category of our Style Scores system with a strong Zacks Rank. The Zacks Rank is a proven strategy that targets companies with positive earnings estimate revision trends, while our Style Scores work to grade companies based on specific traits.

HeidelbergCement AG and Martin Marietta are sporting Zacks Ranks of #2 (Buy) and #3 (Hold), respectively, right now. This means that HDELY's earnings estimate revision activity has been more impressive, so investors should feel comfortable with its improving analyst outlook. But this is just one piece of the puzzle for value investors.

Value investors are also interested in a number of tried-and-true valuation metrics that help show when 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.

HDELY currently has a forward P/E ratio of 7.63, while MLM has a forward P/E of 21.92. We also note that HDELY has a PEG ratio of 1.14. This figure is similar to the commonly-used P/E ratio, with the PEG ratio also factoring in a company's expected earnings growth rate. MLM currently has a PEG ratio of 1.68.

Another notable valuation metric for HDELY is its P/B ratio of 0.67. 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, MLM has a P/B of 2.82.

These are just a few of the metrics contributing to HDELY's Value grade of A and MLM's Value grade of C.

HDELY stands above MLM thanks to its solid earnings outlook, and based on these valuation figures, we also feel that HDELY is the superior value option right now.