Fiberglass
Rapidly gaining market share, fiberglass doors are known for their resistance to moisture, insects, warping and changes in humidity. Thick outer skins of fiberglass surround an inner foam core and a steel framework that provides strength and stability.

Fiberglass excels at mimicking the colors and grain patterns of real woods such as cherry, oak and mahogany.

Heads up: Single-layer versions can be brittle.

Insulating value: R-4 to R-12

Cost for a 16-by-7-foot double door: $1,100-$1,800.