This week, three Building Products stocks are improving their overall ratings on Portfolio Grader. Each of these stocks is rated an “A” (“strong buy”) or “B” overall (“buy”).

PGT Inc. (NASDAQ:PGTI) is progressing from last week’s rating of B (“buy”) as the company improves to an A (“strong buy”) this week. PGT manufactures and supplies residential impact-resistant windows and doors. In Portfolio Grader’s specific subcategories of Earnings Revisions and Earnings Surprise, PGTI also gets A’s. For more information, get Portfolio Grader’s complete analysis of PGTI stock.

AAON (NASDAQ:AAON) is bettering its rating of C (“hold”) from last week to a B (“buy”) this week. AAON manufactures and sells air-conditioning and heating equipment. For more information, get Portfolio Grader’s complete analysis of AAON stock.

This is a strong week for NCI Building Systems (NYSE:NCS). The company’s rating climbs to B from the previous week’s C. NCI Building Systems designs, manufactures, and markets metal engineered building systems and products for the building industry. Shares of NCS have increased 5.4% over the past month, better than the 0.8% increase the S&P 500 has seen over the same period of time. For more information, get Portfolio Grader’s complete analysis of NCS stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.