Staining a Fiberglass Door

Embossed fiberglass is a low maintenance substitute to the standard wood door. Plus, staining a fiberglass door can be easier than working with wood. The main difference between wood and fiberglass is the type of stain and its application.

Embossed, wood grained, fiberglass can’t absorb the stain like wood. A standard wiping stain will not work. The only type of stain that will work is a gel stain. The same type used on difficult to stain woods.

Some manufactures sell a stain and finish kit available in several different colors. The oil based gelled stains work great and the finish is a user friendly Acrylic Urethane or Waterborne Polyurethane. I have used the kits from Therma-Tru with very good results.

An alternative is to purchase the gel stain and finish separately. My preferred oil based gel stain is manufactured by Old Masters, available in multiple colors and can be intermixed to increase your color choices. The clear finish must be exterior rated, any quality finish can be used.

Procedures For Staining a Fiberglass Door

Staining a fiberglass door can be accomplished either hanging on the frame, attached to each other and vertical (multiple doors) or on saw horses. My preference when staining a fiberglass door is the vertical position and on the frame.

This way I don’t have to handle the door after staining. This is the procedure I will describe. Horizontal or vertical doesn’t matter as long as you are comfortable with the doors position.

1) Remove All Hardware and Weather Stripping

All door knobs and associated hardware has to be removed or carefully masked. Removal will allow the easiest staining and finishing experience.

The only problem is reinstalling a locking mechanism, typically the dead bolt, after staining. Be very careful at this important junction when finishing an exterior fiberglass door. It is very easy to damage the new stain and finish.

Next remove the weather stripping from the frame and the bottom of the door. Most manufactures have weather stripping and sweeps that will pull out. Store these items in a safe place for the duration of the finishing process.

2) Remove Excessive Window Glazing

If your fiberglass door has a window or sidelight(s) you will notice a rubberized caulking extruding onto the glass. Remove all excess glazing with a sharp single edge razor blade.

First carefully score the glazing along the edge of the frame. Using the razor blade scrape the glazing from the glass. Wipe the remaining residue off using a glass cleaner.

3) Clean the Door and Mask

Start with a clean surface by using mineral spirits and a clean white rag. This will remove any residue from manufacturing or shipping. Another solvent that can be used is denatured alcohol.

If excessive dirt or grime is present, soap and water must be used prior to cleaning with mineral spirits. Pay special attention to greasy fingerprints. Allow the door surface to dry completely before proceeding.

Stuck hard material must be carefully scraped off. Any scratch on the surface has the potential to be amplified after staining. Never sand a fiberglass door. It will be ruined.

The glass should be masked with safe release masking tape (blue painter’s tape) and paper. The extent of the masking depends on the application method of the clear finish, spraying requires the most masking.

4) Staining a Fiberglass Door and Sidelights

Two different methods can used, apply the stain with a rag then remove the excess with a brush or apply with a brush only then blend one area into another with the same brush. Both the rag and brush methods work fine.

I prefer to apply the oil based gel stain with a good bristle brush then blend one section into another with the same brush.

The best part about staining a fiberglass door is that any screw-ups can be removed with mineral spirits and a rag before the oil based stain dries. So you can practice on a flat area before committing yourself to staining the entire door.

Staining a fiberglass door using the brush method is easy. With a small amount of stain on the brush apply an even coat in the direction of the grain. Always begin in an unstained area working toward a previously stained area. Work the stain into the grained surface.

Use a fast light brushing technique, blending one section into another. During the blending process excessive stain can be removed from the brush with a clean dry rag. Continue brushing until one section is blended into an adjoining section.

Removing excessive stain with the brush, wiping the bristles on a rag to remove stain, can control the color intensity or a second coat can be applied after the first has fully dried, typically 24 hours.

The rag technique is very similar and is a good option. With this technique a rag is dipped into the stain and rubbed onto the surface. Rub in the direction of the grain. The brush is used to remove excess stain and blend one section into another. Excess stain on the brush is removed with a clean dry rag or paper towels. Allowing the stain to dry for several minutes before removing the excess will darken the color.

Experiment with both methods and consult with the door manufacturer to determine the best method for you.

5) Staining Sequence

Start with the door frame/jamb and brick mold, if made of stainable wood. If primed, staining and finishing is an option but painting looks better. Staining sidelights can be done after the door and the sequence is the same.

Staining a fiberglass door needs be done in a specific order.

  • Begin with the door edges. Remove any excess stain deposited on the fiberglass face with a rag.
  • Now it’s time for the face surfaces. Start with the raised panels and the vertical stile between them. Next is the window frame.
  • Continue with the horizontal rails and complete with the vertical stiles. Always apply the stain in the direction of the grain.

6) Applying the Finish

A clear topcoat must be applied after staining a fiberglass door. Two application methods can be used, brushing or spraying. Both methods will produce great results, with the use of an HVLP sprayer producing the best results possible.

Multiple thin coats are better than two thick coats. Plan on 3-5 coats of clear finish depending on application method.

Provide a dust free environment. Do not sand between coats when finishing fiberglass doors. Dust can be removed with a tack cloth before application and between coats. Before beginning stir the topcoat well. Never shake the can, as this will cause fine bubbles to appear in the finish.

Brush Application
Apply a thin first coat so it just wets the surface. Quickly work the brush into the grained texture. Apply the finish in the same order as when staining. Observe the door for any runs or drips and quickly correct with the brush.

Do not over brush. Over brushing could loosen and lift the stain. If this occurs, wait until the finish is dry then gently wipe the area with a tack cloth to remove any balls of stain and finish. Carefully repair any damaged stain with a small brush then recoat the area before proceeding with the next coat.

Allow the first coat to thoroughly dry then apply another coat in the same order. Three coats are recommended for the best protection.

Spray Application
Either a HVLP or airless sprayer can be used. After filling and priming the sprayer test the sprayer pattern, pressure and volume on a piece of cardboard or plywood. Apply the topcoat in a sweeping motion, first in one direction and then in the opposite direction. Avoid spraying a heavy coat as drips or runs can occur, correct drips with a brush before the coat is dry.

Allow the first coat to dry before proceeding with the following coats. The second application needs to be sprayed the same as the first. Follow with one, or more, coats sprayed in one direction only.

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  1. Steve Pulliam

    We have a wood grain fiberglass door that has been painted white. Can this door be stained with a gel stain so that it will look like a wood door? And if so, how would I do this?

  2. Yes,it is possible. To do this you will need to do one of 2 things;

    1- if the door and existing paint is in good shape, paint the door with a satin oil base paint with a medium or light tan color. This will be the background color for the gel stain. Now stain and finish as usual.

    2- Strip off the existing paint down to the unfinished original surface, apply stain and finish as usual. Be careful to choose a fiberglass safe paint stripper.

  3. Debra Collins

    I want to use gel stain on my fiberglass wood grain door the molding is a primed from Factory can I use the gel on the primed Factory molding and what kind of oil should I use?

  4. Yes a gel stain can go over the primed molding. Any good gel stain will work, Old Masters is a good brand.

  5. Amie

    Do we have to use a clear coat? Or can we just use the stain? I’m worried when it’s time to repair that it’ll be more work to remove the clear coat before staining?

  6. Christina

    After staining and applying top coat, my husband noticed that the stain was darker on one side than the other. Can I put another coat of stain on top of top coat to darken the door?

    • Yes, a second is possible. Make sure to wait for the first coat to dry completely, typically several hours or overnight. If you apply the second coat to soon it could reactivate the first coat smearing it around.

  7. Stacy Davis

    I need to strip the stain and top coat to restrain my 3 year old fiberglass door. I used gel stain and a polyurethane topcoat over factory base. What is the best product and process to use to strip topcoat and stain?

  8. Choose a paint stripper that is fiberglass safe then test it on a small spot to make sure it won’t harm your door. Klean-Strip Fiberglass Paint Stripper is one of the best and is fiberglass safe. Process: Use plastic scrapers and soft nylon brushes, don’t want to scratch the door while trying to remove the finish and stain. Finish up with a washing with plain water. You might need to use Lacquer Thinner after the washing to remove some stubborn spots. This will take time and effort, don’t rush.

  9. Tiffany

    Do you recommend one or two coats of stain? I just worry that with 2 coats it may just look painted. Is one coat durable enough with the urethane coat?

    • More than one coat of stain is just about the look. You can use as many coats as you feel is needed to get the look your after. I would do two coats of urethane for a more durable finish.

  10. Kevin

    What type of urethane would you recommend over a fiberglass door with gel stain finish? Would Minwax Indoor/Outdoor Helmsman Spar Urethane work?

    • The Helmsman spar will work well. I would stick with an oil base product for its ease of application but waterborne urethanes also will work, make sure what is used is recommended for exterior use.

  11. Maureen Gaynor

    Is it possible to get a light oak finish over the tan base of a fiberglass door, or will I have to prime it in a buff tone? Seems that mid tone and darker gel stains are all that I am seeing applied successfully. Also, does the interior side require a top coat?

    • The light oak color is very difficult to achieve over typical dark tan fiberglass. The buff color will be needed. Try to choose an eggshell sheened oil base paint if available, easier to stain over. Plus Old Masters makes the best gel stains, in my opinion. Here’s an example of the color needed (Driftwood by Old Masters) – // Here’s what Golden Oak stain looks like over Driftwood, stain applied with graining tool, //

      Yes you need to seal the inside of the door as well.

  12. Bever

    The lower section of our fiberglass door was weathered. I use a wiping stain instead of a gel stain. Color is fine but not sure what else to do or if I have to remove???

    • All you need t do now is apply a clear coat to protect the new stain color from the elements. Any exterior rated finish will work; varnish, polyurethane or water based acrylic.

  13. Sidney

    My dog scratched the door in several spots on my gel stained/exterior spar varnished door, and the color is fading. After washing and drying the door, I applied gel stain, but the scratches aren’t taking the stain. I have tried re-applying, using a touch up stain marker, with no success. Is there a touch up product for scratches on a fiberglass door?

    • There are no other products I’m aware of that will work in this situation. It is possible the scratches are into and damaged the embossing (wood grain). It is impossible to fix this type of damage. Try an artist brush and the gel stain, carefully apply to the scratch only and reapply when dry if needed.

  14. Kate

    Can I use a solid color oil based stain instead of a gel stain on a fiberglass door?

  15. Louise

    I have a thermatru wood grain front door that is under a porch roof, never receives sun or rain and the original mahogany colored gel stain was never top coated. 7 years later the door dulled because of cleaning with simple green or windex. To refinished this door I cleaned the inside and outside door with lemon pine sol as I read that this product did not require a rinse and did not leave a residue. Then my painter simply restained the door with 118 dark mahogany Zar oil based interior wood stain. One coat. The door is beautiful. My question is must I top coat? I would prefer not to because I may need to reapply another coat of stain and did not want to get involved with taking off the top coat. How long would this finish last without a top coat?

    • Top coating would be nice but since the door is well protected now it isn’t really needed. You should get a couple good years out of the new stain before recoating.

  16. Jeannie

    Just put the top coat on yesterday. Now the door is “filmy” and looks ready for Halloween. It looked beautiful with just stain. Can this be fixed?

    • Need a little info; What top coat was used, how was it applied and what was the weather conditions? Plus, is the door finish cloudy? Can you describe “filmy”? This will help figure out what happened and how best to fix.

      • Jeannie

        It was the Therma Tru top coat that came with the Therma Tru stain. It was brushed on. The weather was mid eighties, clear. The door finish is not cloudy. It was beautiful. The top coat turned cloudy within an hour after applying it.

        • The weather was good and the stain looked good prior to applying the clear finish.

          If I remember correctly this finish is a water based exterior acrylic urethane. Brushing is very difficult with this finish, dries too quickly. Applying it too thick could cause this problem. It should dry/cure clear which could take a day or two.

          There isn’t anything that can be done with this finish except strip and redo with something else, an exterior oil based poly or varnish.

          You should call Therma-Tru and let them know what happened.

  17. Susan

    This is a very helpful thread.
    I have a Jeld-Wen patio door (fir texture) that I need to stain. The colors in the manufacturer’s offering do not match the wood trim in my dining room. I need to test some colors on fiberglass to be sure I have a good match but there was no sample included with the door. I wrote to Jeld-wen but have not been able to get a response. Is there a way to get a sample of fiberglass from some other source to test my stains? Can I test them on a different surface, like a board painted to match the base color of the door?
    Also, what do you recommend for a durable, long lasting outdoor top coat?
    Thank you.

    • Unfortunately getting a piece of embossed fiberglass for stain matching isn’t easy, mostly impossible. Using a painted board is your best bet.

      McCluskey’s Man-o-War exterior spar varnish is a great durable finish. It is probably the toughest exterior clear coat you can get.

  18. Susan

    I had the glass replaced in my fiberglass door and need to know how to stain plastic glasss trim to match stained door. This is on the interior side as we had exterior painted.

    • First you need to prime the plastic trim then paint it a medium tan color, this will match the original color of the door. Could also use a tinted primer, ask you local paint store if they can tint it to a tan color. Now you need some gel stain or heavy bodied wiping stain that matches or comes close to the door stain color. Application is by brush, might take more than one coat. Protect the rest of the door with blue painters tape and masking paper or news paper.

      After the stain is applied and dry apply a coat or 2 of sealer, polyurethane or varnish. Might be a good time to re-coat the entire door.

  19. Dagny

    I just had a ThermaTru fiberglass entry door installed. I painted the outside to avoid the weathering of stain. However, I wanted the wood look inside, so I stained it and the sidelights with Varathane gel stain, Ipswich Pine color, two coats. It looks beautiful now, before I have topcoated. I see someone commented that the inside needs to have a topcoat. Why? I’m worried that putting polyurethane on will ruin the look I have now; it might run or drip, or loosen the stain and make streaks or something. I’m hesitant to do any more since I love how it looks now. Please advise as to reasons for top coating the inside.

    • A clear coat will protect the stain from fading and damage. Applying a clear coat, varnish or poly, can be a challenge but careful and apply only thin coats problems can be minimized. I would choose an oil base finish, fast drying polyurethane is good. Water based finished can present problems as they dry too fast and are harder to apply by hand.

  20. ERIN

    I have just had a therma-try door installed. I stained both sides of the door yesterday afternoon and it came out nicely, other than having to pluck hairs off from the brush supplied with the Therma-try recommended Same Day Stain Kit. Door looks good but, after 24 hours it is still very wet/tacky. Do I need to remove more, even though the door looks good, or will it eventually dry. If I let it go too long without putting on the top coat will there be a problem? Temp yesterday was 67 with 70% humidity. today it is 72 wirh 67% humidity. Thank You!

    • Let it dry. With high humidity and somewhat low temps it could take a few days. Keep check it and when dry apply a clear coat to protect the good looking stain.

    • Dagny

      When I stained my Therma Tru door, even though the stain can said 24 hours, it really took more like four days for it to dry to not tacky at all! I live in Massachusetts and it’s fairly humid so maybe that’s why. But it did eventually dry completely.

  21. Dan

    Do I need to sand between sealer coats? I tried and it started taking off the stain? Says on Manufacture that you’re supposed to sand between coats but it seems like it doesn’t work with the gel fibreglass

    • At most a light careful sanding with 320 or ultra fine sanding block. If you are taking off the clear coat, and getting down to the stain, then stop and apply more clear coat. All your looking or feeling for is having no dust on the door.

      Using a take rag alone might be enough to remove any embedded dust.

  22. Dean

    I have a fiberglass front door that was stained and covered with an unknown type of top coat. The sun has impacted the door and I want to refinish it. I’ve read a lot of things, but am unsure of the best way to proceed. Should I sand the door to get the existing top coat off? What’s a good exterior stain and is marine varnish a recommended topcoat? I’m open to your recommendations. Thank you for your assistance.

    • Exact procedures depends on the door. Sanding is great for flat areas and solid wood doors. Intricate details are hard to sand. These areas will require using a paint stripper. The same paint stripper could be used on the entire door then sanded later to finish up with a smooth surface ready for stain.

      No need to use a special exterior stain. Ant regular wood stain will do since you will be protecting it with a clear coat. I do recommend McCloskey Man-o-War spar varnish, good results over many years of use. It will do well applied over any proper wood stain.

  23. TS

    Hello – fiberglass front door had some damage from dog scratches. Unmistakably sanded before realizing it wasn’t a true wood door. Planning on stripping and re-staining, but wondered if there was any solution to make sanded areas where scratches were better? I hear using a Bondo fiberglass resin and repair kit might work, similar to how a wood filler/putty would for a wood door.

    Thank you.

    • If this is a smooth fiberglass door then the Bondo will work. But, this sounds like a door with a wood grain texture. In this case give it a try but probably won’t work well as it will leave the sanded are smooth not wood grained. Good Luck!

  24. Karina Reinert

    Everyone on here is talking about staining but I was wondering what kind of paint is best to use on a fiberglass door. Everything I have read says to find out if it is epoxy fiberglass or polyester but I can’t find that information any where. It is a jeld-wen door.

    • The type of fiberglass, epoxy or poly, is irrelevant as the door will need priming anyway. A good universal acrylic primer will work well. Any type of paint can be applied to the door, the same type as your house is fine. Better the quality the better looking and longer lasting is the paint job.

  25. My fiberglass door is stained with gel stain and finished with poly sealer. Do I have to strip before restraining?

    • Not necessarily. If the existing stain and finish is in OK shape then just (1) a good cleaning, (2) very light sanding to remove any embedded dust, and (3) final cleaning with a solvent deglosser is a good base for the application of more oil based gel stain and then finish.

  26. Heather

    Did you stain and treat the white trim around the window the same as the door? We have new doors with full length windows with the white trim.

  27. Jackie K

    I have a PlastPro fiberglass sidelight and the stained insert (only) has peeled off three times since its install in 2012. I prepped properly and used a PlastPro Stain Kit each time. I finally inquired with the company I purchased it from and when they saw the insert is white, they’re “guessing” I was given a paintable insert (with the fiberglass sidelight) that may not have been prepped for stain from the factory. They offered me a Stain Mate spray to use that will make it stainable. Being that I really don’t know if the insert is stainable or paintable, I’m wondering how I can ensure that either stain or paint won’t peel again? Thx!!!

    • Paintable and stainable is the same thing. Most likely it is a non-paintable plastic insert. If they (the manufacture) have a primer (the Stain Mate in question?), then use it before staining. You could try a different stain, like Old Masters gel stain, and see if that sticks. Otherwise, you will need to prime the fiberglass before staining. Finding a primer that will stick could be a challenge.

  28. Esther Maria

    I had some fiberglass French doors installed in my back porch which is roofed so the doors are not in direct sun.
    I decided to leave the original fan color as they come (no stain) and today applied one coat of spar urethane on the outside just so it has a little “finish” look.
    Do I need to give them more coats? If so, how many?
    Do I have to coat the inside?
    I’m a novice in most handiwork things so please explain as simple as possible!
    Thank you in advance for your help.
    Esther Maria

    • 1 coat is enough for now but an additional coat would provide better protection. You should re-apply when you notice the sheen dulling. You can also varnish the interior side is wanted, 1 coat would be enough as long as it looks good. This could help with cleaning but not really necessary.

  29. EM

    Thank you! I will give them an additional coat tomorrow morning then.

  30. Cate

    Hello, I have a new fibreglass exterior front door. It is a smooth finish. I have applied one coat of gel stain and I have done a wood grain faux finish. I’m happy with it but would like it to be a bit darker. Can I apply a second coat over this and will the wood graining finish I’ve created show through, or will I have to re-do that? I’m letting it dry for a day before any second coats, and I plan on using a Minwax Helsman spar top coat. Thanks.

    • It is possible to apply another coat of stain but this will make the background more opaque. Try a they thin coat to see how it goes. Make sure the stain is fully dry and hard before applying another coat as it could lift the previous coat of stain.

  31. Jeff Johnson

    We are refinishing our fiberglass front door. It is the original door and has been refinished before. We are going to use Gel Stain from Minwax.
    Our question is what do we use on the “wood” trim around the fiberglass door? We have sanded the wood trim down. Does this need to be primed & then stained? If so, what color & kind of primer would you suggest if the door color is walnut or dark mahagonay? Could we use the Minwax Gel Stain on the wood trim?

    • You can use the same gel stain if the wood frame and trim is raw, unstained or not painted. If it is painted you can still use the gel stain but a neutral tan background color is needed, satin sheen paint. Also, you would need to replicate the wood grain with the stain. Of course, the frame can be painted either the common house trim color or an accent that looks good with the stained door.

  32. John dewey

    I have gel stained a fiberglass door and I also have spar urethane. I read that spar urethane is for wood but can it also be used as a top coat on my gel stained fiberglass?

  33. Dodocolby

    I ordered a Thermatru door, and I asked to be stained inside and primed outside.
    My intention was to paint the outside. Now I had a change of mind, and want to stain the outside also.
    Can I stain the outside to give it an wood finish? Do I need to remove the primer if I want it stained?

    • No need to strip off the primer. Stain over it with a gel stain or wiping stain (Old Masters is the best stains). If a tan background color is needed use a satin sheen oil base paint (tan color) before staining. The paint will provide a nice background color for the stain. You might need to experiment a bit, keep some clean rags and paint thinner around to quickly remove the stain if you think it isn’t working out and to try another procedure.

  34. I work for a fiberglass door manufacturer name Nova Doors and we use a water based product called TruCoat for painting and staining our fiberglass doors. It is made specifically for fiberglass doors so it doesn’t require any special primers, is super durable and lays down really smoothly –

  35. Darrell Seaton

    I have a thermatru door that was scratched when I had a refrigerator installed, what kind of filler should I use on the scratches. I have bought a kit from thermatru but it does not come with a filler only stain & a top coat?

    • If this is an embossed door, wood grained texture, then there really isn’t anything to do to truly fix the damage. It will show when stained or painted. With that said, use a stainable wood filler. Try to apply only to the scratch and carefully sand when dry. You can also try to add matching texture to the filler when it is still wet using a tooth pick, draw lines the match the wood texture.

  36. Didi

    It is suggested to stain a fiberglass door while it is installed to minimize handling and that only the lock set should be removed. How do you allow for drying time? How to you secure your home if painting the front door? How do have time for staining, drying, sealing and drying again?

    • The door lock is reinstalled when the door is dry enough to accept it. To minimize damage to the stain and/or finish the weather stripping is removed from the frame, this way the door won’t touch anything once locked. The stain is allowed to dry overnight before applying any finish, same is true for the finish as well. So, it take a minimum of 2 days. All of this is best done in good weather conditions to facilitate good speedy drying.

  37. Cary

    I am planning to stain my woodgrain fiberglass door. What color primer should be used on the door if I want to use grey stain?

    • The current color should be fine, if your door is unfinished and you use a quality gel stain. Normally, fiberglass doors are a light tan color that mimics a neutral wood color.

  38. Crystal

    The exterior of my fiberglass front door is smooth and painted a dark brown. I would like to do a faux woodgrain look. What products would I need?

  39. J

    With wood doors, when gel staining, it’s ok to lightly sand and clean prior to applying the gel stain.
    Is this procedure ok with a fiberglass door, as well, if the door is not in really bad condition with original factory staining? Also, can it be gel stained after cleaning only?

    • Wood Doors; Cleaning and sanding is OK, in many cases both are needed. You can either sand down to new clean wood or lightly sand the old finish to get it ready for the new stain.

      Fiberglass Doors; Never sand, this would destroy the embossing (wood grain). Cleaning is all that is usually needed. The cleaning can be a waterbased deglossser or as simple as a mild dish soap with warm water. Either way using the deglosser at the end of the cleaning is a good idea. Allow the surface to dry then apply the gel stain.

  40. Rachel DeYoung

    I have an unfinished fiberglass door with wood grain. I used miniwax gel stain. When it’s time for a top coat, Therma-tru said to do oil based stain and water based top coat. When looking in stores the water based too coats don’t have sun protection. It is an east facing door. Do we need sun protection like the exterior oil based will offer? Can oil based stain be used with oil based top coat?
    Appreciate the help!

  41. Sally

    We have a new fibreglass ‘wood grain’ front door and we used gel stain to stain the interior. It was beautiful and was the exact tone that we wanted until some teenagers came into the house and leaned on the door before it was fully dried. My husband then tried to add more stain to correct it and it’s an even bigger mess. Any tips on how to repair or strip and redo this? Note we have not put a top coat on yet. Thank you for your help.

    • You will need to remove the stain. Paint thinner or lacquer thinner and lots of clean rags will remove it. If it’s just 1 panel damaged then remove just that panel. After the solvent dries reapply the stain. Don’t worry about getting all the stain out of the embossed texture, just what’s on top and get an even looking area. Make sure to have a bucket of water for the rags, put the rags in the water after using and throw away wet.

  42. Vicki

    I have a fiberglass door that is two years old, was stained and clear coated by house painters and I don’t know what they used. It is already very faded, finish is coming off in some places, and it has what looks like water stains after two very harsh winters with snow, and sub zero temps. I’m seeing conflicting advice on here from admins regarding sanding, whether or not to clear coat (seems like stain should always be clear-coated regardless of exposure to elements), and removing existing finish. If I can scratch off the existing finish with my fingernail or wipe it off with a rag, I assume I need to remove it before re-staining but don’t want to use a chemical stripper. Seems like a very light sanding would be okay and not damage the door, then clean well with mineral spirits to remove residue before stain. Based on replies to comments, not sure what to believe. Thanks for your help.

    • Actually, everything you mention is OK.

          Light sanding only to remove loose or flaking finish. No harsh sanding. You can use a brass wire brush, carefully, to remove peeling finish in the wood grain or hard to reach areas. You don’t want to cause physical damage to the doors embossing (wood grain).
          Stripping is OK if the stripper used is sale for fiberglass. The more environmentally friendly types should be OK to use. Mineral spirits and lacquer thinner are OK to use.
          Yes, if it is easy to scratch off the stain and finish then best removed before restaining and finishing.
          The stain on these doors needs a finish coat for protection from the elements. You can use any exterior rated finish but the exterior acrylic clear coats are the best. They are a little difficult to use however, apply thin coats only.

      I think some confusion comes from the idea of sanding the fiberglass. It’s not so much a sanding as a gentle removal of peeling or flaking residue. Using a scrubber pad with soap and water can be a good choice. Chemicals alone is often a better choice for many but a combo can be used with care.

  43. Vicki

    Thank you so much, that is very helpful!

  44. Kimberly Mendez

    Hi we are applying the one day stain kit when applying the stain should the stain be completely wiped off after the 15 minutes also it says to wipe off excess stain does that mean some of it or all of it

    • I like using a brush and applying to the finish color/intensity desired, then allow to dry. Wiping is difficult to do as it leaves streaks and a blotchy appearance. If you decide to wipe, just carefully remove any excess stain not all of it.

  45. Jon

    I just re-finished my ThermaTru fiberglass door using their One-Day Stain kit. I stripped the old One-Day Stain and applied 3 layers of mahogany stain. Everything looked great. I then applied my first layer of their top coat (a water-based top coat) and it dried milky and blotchy. I have done this before and did not have this issue. Another commenter mentioned a similar issue. While I tried to be as minimal as possible as I applied it, I am assuming I either applied too much or the product may have been stored incorrectly before I purchased it. Whatever the reason, I am trying to decide what to do to fix it. Can I apply another stain layer over the topcoat (I think this is a no), and then try another topcoat product? Alternatively, how can I remove just the topcoat layer (light sanding?) so I can apply another topcoat product? What topcoat product would you recommend?

    • Unfortunately there is no way to fix this. Possible more time to cure might make some finish less cloudy/milk. Try applying another layer of stain over the milky finish. This should work fine, then apply another type or brand of finish.

      If this doesn’t fix it then you will need to strip everything and start over. Could try a mild stripper to see if it will only touch the finish.

  46. Sharon

    I want to refinish our front door which is textured and painted a flat dark brown. I would prefer the door to look like wood rather than just painted, but don’t know the steps to get there, or if it’s worth the trouble. We will have to refinish while it is hanging unfortunately.. What do you recommend ?

    thank you

    • Your door can still be stained.

      1. Wash with a mild soap then rinse with fresh water.
      2. Paint it a light tan color, think of what raw wood looks like. Use a satin sheen oil base or acrylic paint. Acrylic is easier to use and readily available
      3. Allow to dry overnight then stain the door with a gel stain as normal.
      4. Seal the stain when fully dry. Best to wait overnight.

      This can all be done with the door hanging up. Remove the weather stripping if staining the outside.

  47. Pat Homer

    Hi, We just had our new fiberglass front door gel stained and polyurethaned by people who were painting our house. There are a couple of pretty good runs in the polyurethane. Is this something I can fix with a little sanding? What will the sanding do to the gloss of the topcoat? Is it best to use sandpaper or a fine steel wool? Thank you!

    • It is possible to remove the drip(s) by carefully sanding. Use an artist brush and the original stain to “repair” the stain is damaged. Personally I would call back the paint company and let them fix it. It’s just good business to fix ones mistakes and have happy customers.

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