The best replacement for fiberglass is vinyl windows.

The best alternatives to fiberglass are rated as following:
★★★★★  vinyl windows
★★★★  cellulose insulation
★★★★  carbon fiber
★★★★  steel door
★★★  concrete pools
★★★  steel doors
★★★  aluminum ladder
★★  cellulose
★★  wood doors
★★  gunite pools
★★  acrylic
★★  concrete pool
★★  aluminum boats
★  gunite pool
★  steel entry doors
★  aluminum
★  bondo
★  wood windows
★  aluminum boat
★  asphalt shingles
★  steel front door
★  foam insulation
★  aluminum ladders
★  steel entry door
★  aluminum screen
★  aluminum clad windows
  wood door
  gunite
  plastic
  aluminum canoe
  acrylic shower
  steel garage doors
  aluminum window screens
  wood clad windows
  vinyl replacement windows
  steel door which is better
  vinyl pools
  pebble tec
  aluminum windows
  wood handle
  epoxy surfboard
  plaster cast
  wood exterior doors
  urethane
  tile shower
  concrete swimming pool
  carbon fiber weight
  organic shingles
  acrylic tub
  epoxy surfboards
  liner pools
  vinyl pool
  asbestos
  carbon arrows
  spray foam
  acrylic nails
  acrylic tubs
  steel exterior doors
  wood entry door
  cultured marble
  polycarbonate
  acrylic bathtub
  polyurethane
  aluminum travel trailer
  kevlar canoes
  aluminum screens
  steel exterior door
  aluminum drift boat

Your alternative for fiberglass is not listed? Suggest!
Speaking about fiberglass, one probably shouldn't forget about foam.

Other search terms related to fiberglass and their ratings are:
★★★★★ foam
★★★★ resin
★★★ epoxy resin
★★ kevlar
★★ polyurethane
★★ polyester resin
★ mold
★ cardboard
★ epoxy
★ hardener
★ bondo
★ polyester
★ concrete
You have in mind a companion for fiberglass and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of fiberglass in all years. Click on graph for more.
fiberglass
vinyl windows
cellulose insulation