This week, 4 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”).

Nortek, Inc.’s (NTK) ratings are looking better this week, moving up to a B from last week’s D. Nortek, Inc. is a diversified manufacturer and distributor of building products for residential, light commercial, and commercial applications. The company also gets A’s in return on equity. For more information, get Portfolio Grader’s complete analysis of NTK stock.

Owens Corning (OC) is seeing ratings go up from a B last week to a A this week. Owens Corning produces residential and commercial building materials, glass-fiber reinforcements and engineered materials for composite systems. The company also gets A’s in operating margin growth, earnings growth, and earnings surprise. For more information, get Portfolio Grader’s complete analysis of OC stock.

Trex Company, Inc. (TREX) boosts its rating from a C to a B this week. Trex Company, Inc. is a manufacturer of wood-alternative decking, railing, fencing and trim products. The company also gets A’s in earnings growth and return on equity. For more information, get Portfolio Grader’s complete analysis of TREX stock.

This week, Alpha Pro Tech, Ltd.’s (APT) ratings are up from a C last week to a B. Alpha Pro Tech, Ltd. engages in the development, manufacture, and marketing of disposable protective apparel, building supply, and infection control products principally in the United States. The company also gets A’s in earnings growth and earnings momentum. For more information, get Portfolio Grader’s complete analysis of APT 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.