Exterior paints have a natural resilience to the elements, a condition that can make you doubt their usage indoors. The additives and binders in exterior-grade paints help them hold up well against harsh conditions. You may be wondering if they can be used inside but do not worry, as this article will help you out.

Even though it’s possible to use exterior paint inside, it’s still not usually recommended. This is because exterior paints contain Volatile Organic Compounds (VOCs), additives, pigments, and binders that make them hazardous for use inside.

This article explains all you need to know about exterior paints and why it would be a bad idea to use them inside.

can I use exterior paint inside

What is Exterior Paint?

Exterior paint is made in such a way that it can withstand blistering sun, sandblasting winds, torrential downpours, and also earth-shattering cold. Exterior paint withstands the elements when applied to buildings.

Most exterior paints have more resin constituents and tend to be softer than interior paints. It is to help them adjust and get used to the temperature and environmental extremes.

Exterior paint can be oil-based or water-based. The base is the solvent that evaporates, while the binders hold the additives and pigments together to make the paint firm. Water-based paints dry faster than oil-based paints, and this is because water evaporates more quickly than oil

Bases

Exterior paints were commonly oil-based; however, recent formulations have made some water-based paints as excellent as oil-based paints and even better.  Linseed, tung, soybean oil, or synthetic alkyds make up the oil base, while water-based paint has water as its base.

Both paint types contain Volatile Organic Compounds (VOCs). However, oil-based paints tend to emit more VOCs than water-based.

Pigments

These are organic or inorganic that give the paint its color. White is inorganic in composition. Plants and animals are the sources of organic pigments, while inorganic is from minerals. Organic pigments give a more transparent color, and inorganic pigments are more solid and the more the pigment count, the richer and more solid the color. The pigments in exterior paints help prevent fading due to sun, UV, and weathering.

Binders

Binders help hold the pigments and additives together to produce the paint film on different surfaces. They are also formulated to tolerate harsher exterior conditions than those used on interior surfaces and walls.

Additives

Pigment, binders, and additives are carried and spread by the water in water-based paints or by mineral spirits in oil-based paints. The water or mineral spirits evaporate, leaving the dry paint film behind. Additives are constituents of the paint that thickens the paint. In addition, they also fill holes, level, are more durable, harden, stick to different surfaces, and resist UV and mildew.

Additives also include texture and reflective additives, including scents to mask paint chemical smells. Exterior paints contain more additives than interior paints, and these additives vary. The additives in exterior paints allow them to withstand harsh environmental conditions.

Can I Use Exterior Paint Indoors?

There is no doubt that exterior paints are often more durable than most interior paints; however, it is not advisable to use them indoors. It is because exterior paints produce toxic fumes even after drying; thus, they will continue to off-gas VOCs until cured.

The drying time for paint is 2 – 3 days, but the curing time takes longer, so exterior paints can continue emitting toxic VOCs for many weeks after using it inside. The VOCs emitted are dangerous to humans and pets and should not be inhaled.

The table below explains VOCs commonly found in exterior paint and their effects on human health.

VOCSEFFECTS
FormaldehydeCauses irritation of the eyes, nose, and throat. Also causes choking and coughing
ChlorideBlurred vision, dehydration, burning, and redness
MethyleneRespiratory tract irritation, and can also harm the heart, skin, liver, and heart
BenzeneCauses drowsiness, dizziness, headaches, respiratory tract irritation, and unconsciousness

However, some exceptional cases permit you to use exterior paint inside, which include:

Painting a Storage Shed or Other Outdoor Building

You can use exterior paint inside if you are painting a storage shed or outer building. It could be a detached garage or pool cabana where no one lives. Such a room is rarely occupied. Thus, you cannot be affected by the toxic fumes from the room, and neither will the toxic fumes affect your pets if you have any.

If you use exterior paint for a shed or other outdoor building, there is a low possibility of you or your family getting affected by the VOCs. Therefore, using exterior paint for such indoor area(s) would be a perfect way to utilize any leftover paint.

Vacant Room

If you have a room you rarely use or are sure not to use for several weeks or months, you can use exterior paint. Meanwhile, it would be best if you opened the window to such rooms to release gases while it cures.

The materials used in the production of the paints will be less harmful if there is excellent ventilation within the exterior. Therefore, if you open the windows of the room, there will be an improvement in the ventilation which will permit the VOCs from these paints to escape.

After using exterior paint, you must stay away from the area until the paint cures or finishes off-gassing. It will help limit your exposure to fumes and guarantee safety despite using such paint.

Dangers of Using Exterior Paint Inside

One of the dangers of using exterior paint inside is exposing you/ your family to volatile organic compounds that paint emits while curing. Also, exterior paints contain additives and binders and produce toxic fumes for many weeks after drying. The fumes it produces can cause diseases to humans and pets; thus, it is dangerous to use inside.

As the name implies, exterior paints are best used only outside as the ample ventilation outdoors will help diffuse the VOCs, thus, rendering them harmless.

If you are left with no choice but and use this paint inside, then you will need to take serious precautions, which may not be effective in a family setup. The harmful paint fumes can last within an enclosed indoor space for as long as six months.

When using this paint indoors, you must take serious precautions, which may not be effective in a family setup. The hazardous paint fumes can last within an enclosed indoor space for up to six months which means someone can be subjected to the dangerous fumes for a long time. Also, if you have an air conditioner in your home, it could spread the paint fumes, therefore, posing more threats.

It would benefit you if you could stay away from areas where the paint fumes can be perceived or, best still, never use exterior paints inside. It is because inhaling the paint fumes could cause dizziness, light-headedness, and other uncomfortable feelings. In addition to this, exterior paints possess strong odors that can trigger allergic reactions in people having allergies.

Differences Between Interior & Exterior Paints

You can know the differences between interior and exterior paints based on the specifications of their respective containers. You might be wondering how this is possible. Kindly check below:

1) Most Interior Paints don’t Have Latex

Interior paints are mostly acrylic latex, although these paints do not often contain latex in their formula. In contrast, exterior paints are acrylic latex, but they have a latex component added to their formula. Exterior paint contains resin, who h makes it weather-resistant and flexible enough to tolerate the extreme temperature changes outside.

However, interior and exterior acrylic latex paint types are water-soluble when damp, but when they get dried, you will notice the difference between them.

2) The Cure Time Of Exterior Paint Is Longer Than That Of Interior Paint

Exterior-grade paint contains many added ingredients, which include binders and other additives that affect cure time, thus, making it longer.

These additives indeed help make the product more resilient and perfect for use within harsh outdoor environments. They also influence the paint’s cure time by extending it. Exterior paint requires several months to cure but will continue releasing toxic fumes throughout that cure time; this is a significant reason why it is not suitable for use inside.

3) Interior Paint Has Less Odor Than Exterior Paint

Interior paint has less odor compared to exterior paint because they have lesser additives and binders, which enables them to stop the emission of any noticeable or offensive smell soon after you apply them on interior walls and other surfaces.

In contrast to interior paint, exterior-grade paint contains more toxic additives, including UV blockers and fungicides. The potent constituents in exterior- grade give the paint a strong odor. The powerful components with a pungent odor can cause allergies to individuals having smell sensitivities after applying it.

4) High Level Of Volatile Organic Compounds In Exterior Paint

Exterior paint emits VOCs until it’s cured, although it may take several weeks or months to cure in warm weather. If it is used indoors, it can take up to six months.

In contrast, indoor paint contains less dangerous chemicals. Also, you need not worry about side effects as the side effects are not noticeable, unlike inhaling exterior paint fumes, which can cause dizziness, headaches, nausea, and light-headedness.

5) Different Chemical Composition

Interior and exterior paint have different chemical compositions and properties. The properties of exterior paint are the reason why it resists sun damage, cracking, chipping, water damage, and discoloration from molds and other fungi.

As for interior paint, it is formulated for easy cleaning without damaging the paint layer, which makes it easy to clean with soap and water. In addition, its formula is designed to resist stains and keep indoor spaces spotless.

Usage of various exterior paints inside

Latex Paint

Things you should keep in mind to use exterior latex paint inside.

First, exterior latex paint is designed to withstand weather and temperature extremes, so it may be more durable than interior paint.

However, it also may contain volatile organic compounds (VOCs) that can off-gas into the air.

So it’s important to ventilate the area well while the paint is drying.

It can also be more difficult to clean up if it gets on your walls or floors.

Secondly, exterior latex paint typically has a more intense color than interior paint, so it can be more difficult to match to your interior decor.

Finally, exterior latex paint can have a strong odor, so be sure to open windows and doors to ventilate the area while you’re painting

Trim Paint

Yes, you can use exterior trim paint inside your home. This type of paint is designed to withstand the elements, so it will be durable enough to stand up to daily use inside your home. Plus, exterior trim paint usually has a higher gloss level than interior paint, so it can give your rooms a bright, fresh look.

But at the same time, they include more chemicals and other harmful pigments that could be a huge issue for some people. So, it is best to avoid using exterior trim paint inside.

Weathershield Paint Indoors

Weathershield is a commercial-grade epoxy paint that has been used on both outside and inside projects, although it was not designed for interior use. It has an “elastomeric” additive, which makes it flexible and impervious to cracking, peeling, and flaking.

On the other hand, this paint will not fade and has been shown to last up to 25 years without signs of deterioration, although you should always reapply paint every two to three years to maintain a good exterior.

Valspar Exterior Paint

No, you should never paint a room with paint meant for exteriors. Technically, it is possible to use exterior paint on the walls, but it is not advisable.

This is because exterior paints are designed to withstand harsh exterior environments like sunlight and rain. These paints contain heavy-duty chemicals in them, which may damage the interior of your house.

However, Valspar has paints that are meant for both interior and exterior. and if you buy those, you could use them inside your home with careful consideration. Even then, make sure to not use it in the bedroom or unventilated rooms.

To use it inside you will also have to make sure your home is prepared for it. This means that your wall surfaces and ceiling have to be cleaned and primed.

This is probably the hardest part because if your walls are dirty or have other stains you will need to remove them. After cleaning your walls and ceiling, you will need to paint primer on the walls and ceiling. Make sure that you are using a quality primer.

Glidden Exterior Paint

Yes, you can use Glidden exterior paint inside. However, it will not last long. It is designed to be used outdoors and that is where it will perform best.

It also depends on the type of Glidden Exterior Paint you use. The key to using exterior paint indoors is to use oil-based paint. Oil-based paints stick better to the wall and are less likely to peel than their latex counterparts. Oil-based paints are also more resistant to the effects of moisture, which can be a big problem inside a house.

However it may be tempting to use this type of paint inside your home, it is not recommended. The chemicals and ingredients in Glidden exterior paint are not meant to be used indoors and could be harmful to your health.

Sherwin-Williams Exterior Paint Inside

Yes, Sherwin-Williams exterior paints can be used in interior paint applications.  Sherwin-Williams has a line of paint called “Exterior Plus” that is specifically formulated to be used as an interior paint as well.

Sherwin-Williams also says that if a homeowner were to use regular exterior paint and were to use a stain-resistant primer, it could be used inside as well.  However, it is always a good idea to check with the paint manufacturer and see if it is ok first.

Sherwin-Williams exterior paints are designed to withstand the elements, so they can definitely stand up to the everyday wear and tear of indoor use.

However, because it is designed for outdoor use, it may not provide the best coverage or color selection for your indoor project. If you’re looking for a paint specifically designed for indoor use, Sherwin-Williams has a great selection of interior paints to choose from.

Exterior Paint Inside My Bathroom

It’s not a good idea to use exterior paint inside your bathroom. While it may be durable and easy to clean, it’s not designed for the humidity and condensation that are present in most bathrooms.

Over time, the paint will start to peel and flake, and it will be difficult to touch up. If you’re set on using a particular color or brand of exterior paint, ask your local paint store if they have an interior version that would be more suitable for your bathroom.

Exterior Paint Inside A Garage

One of the biggest mistakes you can make when painting a room is painting a room with paint that shouldn’t have been painted. Those rooms include attics, bathrooms, kitchens, and garages.

Please, do not paint a garage with exterior paint.

The paint on the walls will not last very long at all, and the fumes in a garage will make you sick. Some exterior paint can be used on interior walls as well, but that doesn’t mean you should do it.

But it’s your home and your choice, so if you decide to do it, make sure you use the right paint and do the job the right way.

Can I Mix Exterior Paint With Interior Paint?

It is not ideal for mixing exterior paint with interior paint as both paints are not formulated the same even if they have the same base. Exterior and interior paints do not have the same binders, pigments, and additive compositions.

Exterior paint can withstand sun, rain, humidity, snow, and wind, including other outdoor extremes. It possesses adhesion and elasticity requirements that an individual cannot find in interior paints. The chemicals and other ingredients used in exterior paints do not make it fit for mixing with interior paints.

If you must mix exterior paints with interior paints, then it would be best to dilute the exterior paint, which should not be able to withstand the extremes of the outdoors. There are more chemicals and VOCs in exterior blends that make it unfit for usage indoors.

In addition, exterior paint possesses different levelers than interior paint, binders for surfaces asides from drywall, including additives made for harsher conditions. Thus, while it is easy to pour interior and exterior paints into one can/bucket, know that such an action won’t give you your desired results.

Painting surfaces with a blend of leftover interior and exterior paint often produces a film having diverse texture, drying time, durability, and adhesion qualities. The finished results may flake, crack, bubble, or peel. In addition, if the hues are initially the same, that may also change. Thus, it would help if you don’t mix both.

Can I Use Exterior Paint On The Inside Of My Front Door

This is actually a very common question and not something we never thought of before, but it is indeed a definite possibility. The key to doing this is to make sure to pick up paint that is made to go with both interior, as well as exterior walls.

There are several brands on the market that have this feature, as well as a specific interior-exterior paint that you can find at your local retailer.

We recommend that you do some research and pick up a few samples of paint from the brands that you are interested in, and then do some test patches on your door, to make sure the paint will not peel or chip away when exposed to moisture. If it looks good, then you can go ahead and use the same brand and color to paint your entire door.

Verdict

It is possible to use exterior paint indoors, though not advisable. Also, exterior paint releases dangerous fumes even after it dries and also, may require weeks to months to cure fully. The exterior paint’s finish is flexible and softer, which doesn’t make it suitable for interior walls or surfaces. You shouldn’t use exterior paint inside except if it’s a room, which you rarely enter, and also, it would be best if you opened the windows of the room.

FAQs

1) Can I Use Exterior Paint Inside My Garage?

Never use exterior paint in your garage, including other interior rooms. If you need paint for your garage, you can get acrylic latex paint as this paint type is durable, dries quickly, and is easy to clean. Interior latex paint is the best paint type for garage walls and ceilings.

Although oil-based paint is an option, the qualities of interior latex paint make it a better option, and some of the qualities are:

  1. It dries faster
  2. It can be thinned with water since it is water-based
  3. It has less odor and vapors than oil-based paints.

2) Can I Use Exterior Primer Inside?

Exterior wall primers are unsuitable for interior walls and vice versa. This is because drywalls are porous surfaces that absorb so much paint and can make the overall application blotchy and uneven. A wall primer helps to level the gaps in the drywall and also smooth out the rough surface.

3) Is It Possible To Paint Interior Paint Over Exterior Paint, And Can I Paint Over Old Paint Without Sanding?

It is possible to paint interior paint over exterior paint, and this is done technically. However, you need first to use a primer as it will aid its binding. As long as you use a primer, binding won’t be complex, and it will be easy for you to paint an interior paint over an exterior one.

If the old/existing paint is of the same type you want to use, then,