How to Stain a Fiberglass Door {To Look Like Wood!}
May 15, 2025
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How to stain a fiberglass entry door in a rich wood color.
One of the most common questions I get is about the stain we used on our wood
front door. Turns out our door isn't wood, but it is stained to look like
it.
Did you know you can stain a fiberglass door and it will look just like wood?
I didn't realize this until we built our current house.
I had no idea you could use stain on anything but wood, and I've been at this
DIY thing for a long time!
We have a Therma Tru door set with sidelites (see specifics of our
indoor and outdoor home finishes here) and picked the stain color called English Walnut.
Our front door doesn't get much of the elements because it's protected on our
front porch. But even without the wind and rain hitting it directly, the dark
stain was still super faded nearly eight years later.
I'm prepping for our son's high school graduation party, and this DIY project
was on my list! The process wasn't nearly as difficult as I thought it would
be. There are only a few simple steps in this application, they just take some
time.
The before photos of the door finish didn't look as horrible as in real life,
but it was faded, worn out and chipping in some spots:
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Our builder didn't do a great job the first time this door was stained, so we
had a lot of areas (particularly in more detailed spots) that were chipping
away completely:
The builder left some of the leftover product, so I was able to look it up
online and order more stain.
I went with the dark, rich English Walnut again in
this same-day stain:
This is actually a gel stain and is much thicker than your
traditional oil-based stain. That consistency is really helpful when
staining a vertical surface like a door!
The thicker gel stain makes it much easier to apply with the door on its hinges and it doesn't drip all over the place.
The first thing I did (after taping off the windows on the door and
sidelites) was to sand everything well. I used an 120-grit sanding block on
everything:
These
angled sanding blocks
are perfect for something like this that has a lot of hard to reach detailed
areas. The angled sides make it so easy!
I spent most of my time working at those chipping areas -- I didn't want to
stain just to have more of it flake off later. Sand those areas until smooth
and no longer chipping.
The flat areas were quick and easy, I just did a light sand all over the
door surface and trim:
Make sure to use a damp rag to wipe all of the dust and debris before moving on!
If you hate sanding as much as I do, and your door is in good condition
with no chipping stain, you can use mineral spirits to clean the door
before staining as well. Use a clean rag to apply the spirits, and then let
dry.
Recently I've started using odd socks to apply stain. The soft cotton works
great and I like that I'm getting use out of them! You can see how thick the
stain is here:
I like using a cloth for stain when I can, as it just penetrates better into
a textured surface like this:
Gloves are a must, even if you're using a brush or foam brush! No matter how
hard I try, I always end up with stain on my hands.
You can see what a difference the new coat of stain made here:
This color is gorgeous!
For detailed areas I used a chip brush to get into the hard to reach
spots:
A few more tips for staining a door:
- Do not shake your stain container, as it will create bubbles. Use a stir stick of some kind to make sure it's mixed well.
- I applied stain to the door just like I paint a door -- I work on detailed sections of the door first, then move on to flat sections like the stiles (vertical sections) and rails (horizontal areas).
- Apply the stain in long strokes in the direction of the grain.
- Gel stain doesn't dry as fast so you don't have to work as quickly compared to thinner oil-based stain. It also gives you a bit more time to clean up any drips.
- You do not need to take the door down to paint or stain. You will need to be able to keep the door open slightly for the products to dry. I found that everything dried very fast outside.
- It's helpful to remove door hardware if possible. If not, either cover with painter's tape or wipe away excess stain on the hardware immediately. I didn't even tape off ours, just wiped it off the metal as I worked.
- If starting with a bare fiberglass door, I would recommend a minimum of two coats to get the best coverage. Because our door had already been stained once, I only needed one coat.
- More coats will give the door a darker appearance. Be sure to give the stain enough dry time between coats.
After applying, I waited about 15 minutes and then wiped the excess stain
away with a clean rag (AKA my sock).
If you are staining a door in hot weather, I would clean off the excess in five to ten minutes to be sure it doesn't get tacky.
You don't have to tape around windows, but taping them off with
painter's or masking tape makes clean up much faster:
The stain can be removed with a flat razor afterwards, but it can get gummed
up under the mullions so I find it easier to tape the windows.
Once the door is completely dry, it's time to add a polyurethane sealant on
top to protect all of your hard work!
We had plenty of this topcoat left from the builder, which is what leads me
to believe that it wasn't used on this side of the door from the
beginning:
At the very least, it was a veeeery thin coat.
I always apply polyurethane with a foam brush. It makes for the easiest
application and clean up:
You don't want to work the poly too much, because it will start gumming up
as it dries. That milky finish is fine when applying -- it will dry
clear!
But you also don't want the wet poly to be too thick because it will
create a thicker texture when it dries. (And will take much longer to dry.)
Most any high quality, exterior grade (with UV inhibitors) polyurethane would work on an exterior door, you don't have to use this specific brand.
Our poly was low gloss, but it still gives the door plenty of dimension and
shine. The final result gives the door a beautiful, protected satin
finish:
You can buy this Therma Tru same day stain by itself, but if you are
starting from scratch, I highly recommend
their whole kit. It comes with everything you'll need, down to a pair of rubber gloves and
stir sticks.
Important note:
Be sure to dispose of your application tools, clothes and rags
properly!
Any oil-based finish can become combustible. Check out
this video
for helpful tips.
Here's another look at the bottom portion of the door before:
And the after with one additional coat of stain and poly:
Just gorgeous! I kept walking outside just to look at it! 😂:
That
extra wide coir welcome mat
has lasted nearly eight years! I just ordered a new one -- highly
recommend.
Now our guests will be welcomed with a beautiful dark walnut door instead of a
faded and worn front door! The colors in our
beautiful floral spring wreath
looks so great against the dark stain:
This project took me about four hours over two days. I sanded and stained on
one day and then added the protective sealant and cleaned up on the
second.
Did you know you can stain fiberglass? I learn something new every day! If
you've already painted your door and want this stained look, you can remove
the paint completely before staining.
In my opinion, both stain and paint on exterior doors require similar
upkeep. Latex painted doors will fade after being exposed to the elements
and will need a new coat every five years or so.
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