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Can You Use Exterior Paint Inside? Be Careful Here!

Please be careful—using exterior paints indoors is poison! We all want to re-use and recycle, (and save money). I was recently asked in an email, “Can you use exterior paint inside my bathroom?

Answer: There is a major safety hazard here, even if your old cans of paint are still good, you will not be saving money trying to use exterior paint inside. You’ll likely get sick or at least collect toxins in your body. Plus exterior paints are softer to expand and contract outside: not the best for interior painting.

We have a section below on how to find low-cost, good paint.

Bath Paint: If you just want a decent low-cost bathroom paint, start with Kilz Kitchen & Bath Primer,  ONLY IF you need a primer. (Read why you might not here.)

Add to any paint: If you are looking for a way to keep mildew from growing in a high moisture area, add a mildew-scide to your interior paint. It’s not expensive at all.

Mold-proof paint: Need paint for high moisture areas: Use Zinsser Mold and Mildew-Proof Interior Paint.

Our tool page for every basic professional painter’s tools at the best prices we can find
Can You Use Old Paint? Yes, If Your Paint Passes a 3-Question Test

What’s the difference? 

Exterior Paint on wallThe difference between interior and exterior paint is that exterior paint contains a lot more toxic chemicals. Additives that make exterior paint softer, so it can flex in the extremes of outdoor existence. That is why it is not always a good idea to use exterior paint inside.

Exterior paint contains fungicides, mildewcides, and UV blockers that are toxic anywhere. Using exterior paints indoors will expose you and your family to harmful chemicals—if you use exterior paint inside, that is forever.

If you can’t use it, what can you do?

Exterior paint in can

There are lots of great community recycling programs, (find yours here)…but if the old paint is beyond help…

If you cannot save all that leftover exterior paint for the next time you need it, there is a product to quickly turn old paint into a solid for safe disposal. Paint in landfills leaks and pollutes our drinking water. These powder packets treat 12 gallons.

Tempted to be using exterior paint inside? You will be hurting your real bottom line: your lifespan!

Once in a blue moon: “Can you use exterior paints indoors?”—Yes if…

One time we can say that you can use exterior paints inside is if the area is a storage shed or other outdoor building (pool cabana or detached garage) where nobody sleeps. In that case, using exterior paint indoors would be a great way to use up the old paint.

Just stay away from the area until the paint cures (off-gases), which takes some weeks in the summer, or months when it’s cool out. Doing this, if you don’t have good ventilation, use a respirator. We simplified the complex filters/masks of those products.

How to find low-cost paints

There are alternatives to using exterior paint inside. Reduced-cost, high-quality paint is available at most paint shops in the form of ‘mis-tints’. These are gallons of paint that came out slightly wrong. You just have to accept the colors available on the store shelf at the time. Look for bathroom paints, especially Zinsser Mold and Mildew-Proof is very reasonably priced.

Bottom line regarding the question ‘can you use exterior paint inside’?

Using exterior paint indoors is a bad idea, but only in outdoor sheds or a pool house etc, can you use exterior paint inside. So to my reader who emailed us asking, “can I use exterior paint indoors?”, please don’t try to save on paint this way.

Related: be sure to read our complete list of every painting tool you could ever need.

Did we leave anything out? Let us know in the comments below.

Children are especially vulnerable to toxins in paint

52 thoughts on “Can You Use Exterior Paint Inside? Be Careful Here!”

  1. My brother painted under my mum’s bath with waterproof roof paint, thinking it would make a good damp proofer. What can I do to remedy this cos mum can’t bare the smell?

    • Tell your brother to get a scraper and start scraping.
      WHen he gets 95% off by force, then switch to a paint remover. You could try the proper solvent for the paint… paint thinner if the roof paint was oil based…
      Just keep at it…or buy a new tub.
      Good luck

  2. Hi Brad,

    This is so unlike me—I usually Google BEFORE I do something like this. I was painting the exterior of an entry door in the kitchen. Then I had the bright idea to add the paint to the interior side too. A week later, I googled whether this was a good idea and stumbled upon your page. I called Valspar and they recommended I paint over it with their bonding primer and then add a coat of interior paint over that. But after reading your page here, I almost think I should just buy a whole new door, which would make this a $700 mistake. Is it worth it though? It’s in our kitchen and my children and I do spend time in there.

    Thank you for your insights.

    • No need for a new door, unless you want one. Doors today are great insulators so if the old one was wood, it may be a good time…
      But…You can do what Valspar said, or you can strip it all off, or you can just ventilate your house for some time… a few weeks.
      I’ll explain.

      The toxins in all paint off-gas as the paint cures, and curing takes a few weeks in the summer…longer in winter.
      You will have some types of chemical in the plastic that is exterior paint forever unless you strip it, but in my view, they cause no serious health risk once cured. Just my opinion, but check with the local health department if you are unsure. This is just an opinion…having never seen the door and not knowing the paint and all.

      To be safe, strip it or replace it: yes. To be less safe, primer with a good oil primer (sand first wearing mask and gloves etc), then paint.
      To be even less safe, leave it and let it off-gas. Keep children away if you can and keep airflow going from the door TO the outside.

      • Thank you for the reply! I did find information on the paint and it says it has <50g/L VOCs. I wonder if using chemicals to strip it would release even more toxins into our home.

        • Well, yes it will but the chemicals will mostly not be airborne, but turn into jelly in the toxic stripper goop. It’s a big mess, but it would solve the problem. Ventilate and wear a respirator. Read my post about my respirator on this site.

  3. our contractor used exterior acrylic latex paint on our crown molding in living room and hall. Is this safe? What can be done?

    • He’s a doofus. Or she.
      Keep it ventilated until the paint has cured. This means 2 weeks in summer or cool temps maybe a month. It needs to off gass all the chemicals, then it’s safe. This is according to what I have read. You really should consult the paint maker to be totally sure.
      Good luck!

  4. hi! i painted a very small section of my room with exterior paint. it’s a closet, just without doors. However i’m worried after researching that it will continue to emit toxins even after drying! do i paint over it with normal indoor paint or do i strip it??

    • Hi. Ventilate immediately obviously. From my reading the VOCs are gone when the paint is cured, which is a couple of weeks in the summer in general.
      If you have read something that says otherwise, please reply to my email. But I think if you keep children away and keep the room air moving in and outside, you’ll be fine. Remember, we painters were in rooms with old paint loaded with VOCs for decades. It has not hurt me much. Not only that it has not hurt me much. Not only…
      ha ha.
      Write again if you like.

  5. I have used Granocryl masonry paint on one kitchen wall. It says minimal VOC content 0% to 0.29%. Will that make it safe or should I paint over it with gloss emolsion?

  6. I have accidentally used Dulux Trade Weathershield Smooth Masonry Paint 7.5ltr Magnolia (New Formulation) in the bedroom its saying it a exterior paint …how can I make bedroom safe again …please

    • Open the window and leave open for weeks…as much as you can. Once the paint cures, you are safe as far as I know. If very concerned call poison control and ask. Or EPA.
      But for sure keep children out.

  7. HI I was told it was okay to use exterior paint on my walk in basement walls. Should I keep a fan running on low to get rid of fumes?

    • It’s not ok. They offgas for months. WHen totally cured it will be ok, but is it worth it?
      Yes, an exhaust fan for months to avoid breathing toxins. Forget the word fumes. This stuff stays in your body forever.
      Not worth it.
      Exterior paint must flex in temperatures so that add all kinds of stuff you don’t want in your bones.

  8. Help, I painted my 2 bedrooms with exterior paint and the smell is bad, what can I do? Can I paint interior over it?

  9. Thank you so much for this article. I accidentally painted a small area (3 ft by 3ft) in our bathroom with exterior paint. I’ve had a fan going and the window open for a week and still feel sick. Would it help to paint over with interior paint? Thanks!

    • Yes, it would help to encapsulate it with lead encapsulating paint. If you feel sick, maybe it’s best but you should know that the offgassing is probably about done.
      Once it is done, there’s no difference. Exterior paints are softer so they can expand and contract, so do have different components, but I don’t think there is any danger after the off-gassing is done.

      • If that RV gets to freezing temps you would not want to use any interior paint or primer. Exterior paint is made to freeze but interiors will crack. So no, don’t do interior paints. Was the Behr Marque paint the exterior? Hope so. If now, watch it for cracking over the years IF it freezes.
        The smell will dissipate in time. Just crack a window all winter, all year. Good luck.

  10. My question for using exterior paint on the interior is very specific. We are installing an “out-swing door” full view, fiberglass door on our lower level. (It will be painted prior to installation.)
    Since the door opens out, I’m concerned about weather and wear & tear on the interior side, as well as the jamb (which is all on the inside).
    What would you recommend in this situation?
    Thanks for your help!

    • I don’t think that’s at all a problem since it will only be open occasionally. Some water is fine. Doors don’t get very cold on the inside in general so the interior paint will not crack. It would if exposed for a long time (freezing).

  11. We have aired out our home and left for a week and it is still causing dizziness. Again, we accidentally used exterior paint on our interior dry wall. We would like to remove, but how do we proceed without damaging the drywall? What products would we use and technique?

    • You won’t remove it without damage. It’s going to be a mess. If you have to go this way, you have 2 paths in my view (having never seen or smelled it).
      You can take out the wallboard and put new up, then you are certain you got it all, or you can scrape into the wall and ‘skim coat’. Then prime, paint as if it was new wall.
      I’d look for a pro at this point. Get some opinions from older painters, never young ones: they don’t know what us old folks know.
      If you want to do it yourself, get pros in for prices and ask what products and how-to. Generally, skim with drywall compound, but you need to be sure so ask a ‘mudder’.
      Good luck.

  12. Accidentally used Glidden essentials exterior paint for stucco and masonry (guys at Home Depot said it would be good) on interior dining wall that originally had flat paint. Our plan was to paint with something other than the flat that was there and add removable wall pop/paper on top. We chose to pick a basics paint that wasn’t flat so if in the future we wanted to remove wall pop/paper the wall would not be damaged (as stated by wall pop/paper company).
    Feeling dizzy and throat hurting and worried about toxins. Children in home too. Would covering it help or would the toxins leech through either way? Help? Thank you.

    • Ideally, if possible strip it all off and repair the wall where needed which may be a ‘skim coat’ of drywall compound. If that’s too much, open windows, buy a VOC filter and keep the kids away. If you cover with a sealer, the off-gassing will take longer. I’d probably take advantage of this warm weather and let it off gas into open windows and use a filter
      Try AirDoctor
      Good luck.

      • Ps…I’ve heard not good things about units under 500 clams. Too bad but true. But the used market is good for these…someone always needs one for a while and then they sell…sort of like a tool library!

  13. Ok we the a bunch of paints together, about half interior and half exterior with emulsabond added. Painted a bedroom and hallway/ stairway. It is making me sick. How can I either cover it safely or make it safe? I wish I had known these dangers first!

    • So sorry to hear this.
      You can scrape it all off in the best case, or ventialte for as long as it takes, but there is still the health risk in your house and it will take months.
      An air scrubber that removes VOC is best if you choose not to scrape it all off.
      Watch this.

      Here are the best two products. I’ll make a post just for these soon thanks to you!
      EnviroKlenz Air Purifier
      Molekule Air Large Room Air Purifier
      If you do scrape, maybe you can ‘skim coat’ or spray a textured mud since it will wreck your walls to pull it off.
      Send me some before and pics?? …I’ll send you an email soon. I’ll post for others to benefit from your trouble. It will make you feel better!

  14. Would you be able to suggest a type of paint for basement concrete walls? Or would you suggest not to paint them at all?

    Thanks in advance.

  15. I just used exterior latex paint on the stairs in my unfinished basement. Was this a bad idea? Or will I be ok? Should I cover it up with interior paint?

    • Well, yes and no. I’m sure it is dry and while drying is the worst time for the toxins, but it will continue to off-gas for a few months so keep flushing the aire down there: and don’t hang out there if you can avoid it. Keep your door closed to keep the fumes out of your upstairs. In the end, it will be ok, but be vigilant for a few months.

  16. So I accidentally primed with an exterior primer in bathroom & only realized it because I got dizzy. Should I cover it with an interior primer or just go ahead & paint over it. I am assuming painting over an exterior primer with interior paint will be ok? HELP

    • Hi. The first thing to do is close the door and open the window..and try to stay out.
      Please read the reply to the same question someone asked me last week, just above your question. If it does not work for you let me know: I’ll be watching this comment page.

  17. We used an exterior paint inside and I have been coughing non stop and I suspect its tve paint and the smell has not gone.Is has bern 3 months sinve we painted

    Do I need to remove the paint or I can just paint over it with an ondoor paint.Will this cover the smell and clearly the cause of my coughing.

    • Oh, I wish you had found my site first! Well, if the problem is in the bathroom, it’s simple: leave the fan on, or just run it for an hour every 2 hours etc. Move the air.
      The offgassing will continue unless you remove the paint, but if it was me, I’d wait it out.
      Please do me a favor? When you are free of the smell and the coughing, let me know? I’ll add this info for others to benefit from your hardship.
      Removing paint from a wall is nearly impossible: it means really ripping out the wall and putting up new rock. Time for that renovation? Since you just painted, I’d guess not.
      My megar understanding of VOCs is that they mostly are gone by now, but the plastics that continue to cure and offgas must have some VOCs.
      Look up what plants are good at absorbing toxins and get some. This is not a suggestion for those of you looking to paint with high VOC paint and not protect your lungs: this is a low-level slow toxin solution only.
      There are hard to find VOC air purifiers that would be the best solution, but it’s pricey.
      I found 2 models that have good reviews and are under a thousand clams. I’d suggest getting a good one, then put on 2nd had market for half the cost, so you get your problem solved and don’t have to mortgage the house.
      This one is under 800 and this one is about five. ouch, but it’s your long live we are talking about here.
      Others I see can go up to 2000, and are probably better investment for a long term use.
      I was interested in this and I might do some more research and write a post on this. Thanks so much and do keep in touch?

  18. On one hand you’re saying don’t use exterior paint indoors because exterior paints contain mildew-cides, fungicides, and UV blockers. But, on the other hand, you say when painting a moist environment (like a bathroom) to add mildew-cide to interior paint. So, unless it’s just the fungicides and UV blockers that are poisonous, I’m not seeing the logic here. Exterior paint comes with this stuff in it; but, if you add the same stuff to interior paint, isn’t it just as “bad?”

    I’ve got 5 gallons of good exterior flat paint that I picked up for a song. I plan to use it to paint my garage (which is apparently OK). But, I also plan to use it to prime my bathroom walls before painting over the flat exterior paint with satin interior paint. In addition to the question above, wouldn’t the interior paint seal in any off-gas from the exterior “primer” coat?

    • Hi. Well, my understanding from talking to paint reps is that the exterior ingredients, even if the same function as interior ingredients…are very different.
      But as long as you don’t breathe the off-gassing, which takes months in most cases, you will be safe when it is fully cured. But why risk your health for a few dollars. You can save the paint for years and it will be the same savings.
      Yes, I guess it would work as a first coat, but not as a drywall primer. Drywall primers have ingredients that even out the paper/tape/mud so you don’t get flashing. YOur paint won’t do that and every coat will flash. Trust me on that! I learned the hard way.
      I would not risk my health. But if you use it inside, read my article about a respirator:the system I use is not expensive and you’ll be safe on so many other projects.

      When done, ventilate for weeks.
      Finally, no, the latex paint you put over the exterior first coat in the bath will not block the toxins from off-gassing. It will just slow down the off-gassing somewhat.
      I’d spend a few dollars and get low or zero VOC paints and be safe!
      Good luck.

  19. I was told at Lowes I could use exterior paint for the inside. So I painted a bathroom vanity with it. Now I am reading about fumes being an issue. I painted this outside the home. Should I be concerned. If yes do I have to remove the paint and start over or can I just repaint with an interior paint? or do I need to prep surface some way before recoating with interior paint. Thanks for any response.

    • Well, the paint is dry and most of the toxins are gone. Open the windows and put a fan in there as much as you can without overworking your heat bill. Don’t remove it. Next time just go over it. If latex, no special prep, if oil, you will have to sand it before painting over it.

  20. We had painters who used exterior paint when painting the cabinets in our kitchen. I was concerned about that but they insisted and said there isn’t a problem. Is the issue based on health gone once the paint dries or is it always gonna be a health issue?

    • Yes the danger is gone, but those painters are wrong and they endangered your health. Self-taught creeps. The off-gassing is quick, but the curing takes a few weeks in summer, months in winter… so keep the house ventilated until it’s cured…I’d say 4-6 mo.


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