How to Stain a Fiberglass Door

Supplies needed:

  • Gel stain of choice
  • Interior or exterior clear finish
  • Mineral spirits
  • 2” foam brush
  • 2” natural bristle brush
  • Latex gloves
  • Cleaning rags
  • Stir stick
  • Masking tape
  • Phillips’s screwdriver
  • Hammer
  • Padded saw horses

Remove Hardware and Prep the Area

Before you begin, you must apply masking tape along all of the windows and remove all doorknobs and hardware. Depending on the style of the fiberglass door, you can mask the hardware along with the windows. However, we recommend removal. Once everything is removed, the surface needs to be cleaned using mineral water and a clean cloth. Additionally, you will want to scrape off any sealant that has leaked out from the window frame.

Staining the Door

Two different methods can be used when applying stains. For the first method, you can use a rag to apply the product and then use a brush to remove any excess. Alternatively, you can use a single brush to blend in the product, this method is considered the easiest.

It is recommended you test the technique first on a small part of the door before doing the entire door. If you mess up at any point, the nicest part about the staining process is you can remove any mistake using mineral spirits and a rag as long as the oil-based stain hasn’t dried.

Brush Method

Taking a small amount of stain onto your brush, apply an even coat in the same direction as the grain. Apply the product starting in an unstained area and blend into areas that have been stained in the past. Make sure your brush strokes are fast light, removing any excess as you go. If you are not happy with the color, you can control the intensity with a second coat that you can apply once completely dry (24 hours).

Rag Method

Taking your dipped rag, apply the stain rubbing in the direction of the grain. The next step is to take the brush and remove any excess and blend the sections as you go. If there is any excess product on the brush, remove this using a clean, dry rag between strokes. If you want the shade to be darker, allow the stain to dry for a few minutes (2-3) before wiping off the excess.

Staining Sequence

All fiberglass doors must be stained in a specific sequence.

  1. Start with the edges of the door, removing any excess product on the rag.
  2.  Move onto the face surfaces demonstrated in the image above.
  3. Next are the horizontal rails.
  4. Finish with the vertical stiles.


To complete the staining process and lock in the color, a clear finish must be applied. There are two methods of applying finish depending on the product.

Brush Method

Taking a brush, apply a thin layer of finish working it into the grain. The finish should be applied in the same order as the staining sequence. Be careful not to overbrush, as this can damage the stain. Once the first coat is applied, let it dry before applying any more product, you want to aim for three coats of finish. 

Spray Application

Alternatively, you can use an airless or HVLP sprayer. Follow the instruction closely from this product’s manufacturer. After prepping the sprayer, test the spray pressure, pattern, and volume on a piece of plywood or cardboard.  Using sweeping motions, apply the first coat going one direction first, then the opposite going back. After the first coat is applied, allow drying before applying the rest. This method requires 2-3 coats.

Now you can enjoy your finished fiberglass door! If you are looking for high-quality fiberglass doors, we can help. Here at North Shore Door, we carry a wide selection of fiberglass doors and windows. Check out our selection here, or fill out a contact form today to see some options from our showroom.

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