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 mildewcide 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.

Related:
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
How Long is Paint Good For? Until Hell Freezes Over

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!

Children are especially vulnerable to toxins in paint

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

  1. 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?

    Reply
    • 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.
      B

      Reply
  2. 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.

    Reply
    • 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.

      Reply
  3. 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?

    Reply
    • 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.
      b

      Reply
  4. 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.

    Reply
    • 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?
      Brad

      Reply
  5. 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

    Reply
    • 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.

      Reply
  6. 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?

    Reply
    • 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.
      b

      Reply
  7. 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.

    Reply

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