How to Stain the Exterior of a Fiberglass Door

Because fiberglass cannot absorb stain like wood can, you will need to use a gel coating when you stain a fiberglass door. If you are working on an exterior door, this will work just as well as regular stain on a wood door. However, you will need to take a little extra time to make sure that the gel coat is applied correctly so it will adhere to the door properly and provide years of beauty.

  1. Remove all the hardware from the door. Gel stains can adhere like glue to hardware, so you need to remove it from the door rather than just trying to wipe it off as you go.
  2. Wipe down the door with mineral spirits and a white rag. Douse the rag with mineral spirits, then rub the door in the direction of the grain. Even though the door is not actually made of wood, most exterior fiberglass doors do have some type of grain. The mineral spirits will clean the surface and make it more receptive to the stain.
  3. Apply the stain. Use the bristle brush to paint on the gel stain. Coat an area using fairly short, even brush strokes. Once you have gotten most of the stain off the brush and onto the door, spread the stain out further using the brush. Once it has spread as thinly and evenly as possible, redip your brush and continue. Start with the outside edges, move inward and do the raised panels, then finish up with any indented horizontal or vertical design work. As you go, you can wipe off excess stain with a rag. Apply thin, even coats.
  4. Add two to five more coats of stain. Gel stain works best when you apply multiple thin coats. Allow the stain to dry (about an hour in most cases) and then repeat the process until you have the look you desire.

Things You Will Need

  • Screwdriver
  • Mineral spirits
  • Clean white rag
  • Cleaning rag
  • Bristle brush
  • Oil-based gel stain for fiberglass


  • Stain will last longer if you apply a sealer over the gel stain.