Can You Use Interior Paint Outside? [3 Points To Remember]

You may be tempted to use a particular form of paint in your home if you’ve fallen in love with it. Maybe you have leftover paint from painting your interior that you’d like to use on an exterior surface? Using the wrong paints on the wrong surfaces can ruin your home.

What happens when people use the wrong paint for the job? When you use interior paints on the incorrect interior board, it can be troublesome. Using some kind of interior paint on an exterior surface for your home or business can be a major headache.

We’re happy to give advice and suggestions on finding the best possible paints to meet your needs, no matter what kind of paints you’re looking for.

What is Paint?

A can of paint contains a concoction of additives that produces a hard, protective finish for wood, metal, concrete, drywall, and other surfaces. The chemicals that make up the coating are suspended in a solvent that evaporates after the paint is applied.

what is paint

Polymers, which form the surface, binders, which keep it from separating and allow it to cling to the painted surface, and pigments for color are all included in these coating chemicals.

Paints also have additives to control drying time, increase weather resistance, prevent mildew, and keep pigments evenly dispersed in the paint solution.

What are different types of paints?

There are three kinds of paints: interior, exterior, and hybrid, depending on where they are used.

The paints labelled “interior” have specific characteristics that make them suitable for use in an interior environment. Others have a low odor, while others are more immune to spatter. Some have additives to make them flow and level smoother, and some have better coverage. The interior-classified items are only intended for use in the home.

interior paint

Exterior paint covers better, is more durable, and adheres to most surfaces like glue. However, there is a snag. Exterior paints contain chemicals that are hazardous to use in an interior environment. They’re completely safe to use outdoors and pose no danger.

These materials are suitable for both indoor and outdoor use, but they lack the heavy-duty mildew resistance and hardness of true exterior paints. In a pinch, use these coatings on small jobs like doors and/or door frames. These coatings are also effective in garages. This type of product exists solely for the purpose of convenience and performs admirably on interior projects. Not so much on the outside.

exterior paint

Water-based paints and oil-based paints are the two types of paint. Since oil-based paint was more durable and inexpensive, it was commonly used on exterior surfaces. It has, however, been established that it is toxic, if not fatal, to the atmosphere and the people in the region where it is used.

Water-based paint is now the most popular choice for both interior and exterior painting projects. There have been several enhancements to the ingredients to boost adhesion and coverage, as well as numerous other benefits.

hybrid paint

The drying time is much faster than that of oil-based paint, which can take up to 48 hours to dry and render the space unusable during that time.

Surfaces painted with water-based paint are easier to clean and dry more quickly than those painted with oil-based paint. If kept out of direct sunlight, they will not yellow or fade with time. These paints are non-flammable and have a pleasant odor.

What are the main components of paint?

Pigments, solvents, additives, and resins are the same four essential components of both interior and exterior paints. To make a good product, each ingredient plays a different role. Knowing what each part does will aid in deciding which paint to use on any given surface.

  • Pigments:

Pigments are finely ground particles that are mixed into paint to give it colour. Pigments are divided into two categories: prime and extender. Colorants are the pigments that give the paint its actual colour. Organic colourants provide vibrant hues.

pigment

Inorganic colourants have earthy tones and are well suited for outdoor use. They haven’t always been as long-lasting as inorganic pigments, but that’s changing thanks to modern chemistry. Strong mineral colours that occur naturally but are modified for use in paints are known as inorganic pigments.

Inorganic pigments have a long shelf life. Both white pigments are made from inorganic materials, the most common of which is titanium dioxide. Organic pigments are more transparent than finely ground inorganic particles that are blended and suspended in the base since they combine, blend, and disperse in the base. More solid material is generated by a higher inorganic particle count, which results in deep, rich colours.

  • Solvents:

Solvents are the liquids that hold the ingredients together so that the colour can be applied to surfaces. Water is the primary liquid in water-based paints. Paint thinner made from a number of solvents, such as acetone, turpentine, naphtha, mineral spirits, and the like, is used to thin oil-based paints.

  • Additives:

Paint has a variety of properties due to the addition of additives. Thickening agents, levelling agents, surfactants, emulsifiers, and biocides are among them. These aid in colour accuracy, application, adhesion, and the prevention of mildew development.

  • Resins:

To make the paint film, resins tie the pigments together. Oil derivatives, such as linseed oil, are used to make oil-based resins. Resins are a crucial component that has a direct impact on the efficiency of paints.

Interior Paint vs Exterior Paint

Interior PaintExterior Paint
Interior paints have rigid binding resins. They are stain resistant and allow for easy cleaning of interior paint.The resins used in exterior paints are smoother, offering properties that aid in the battle against fading, mildew, temperature changes, and moisture.
Interior paints sometimes contain vinyl acrylic resins to improve scrub resistance and washability.Acrylic resins are used 
When used on external surfaces, interior paint suffers from a lack of such environment-specific additives.Exterior Paints also contain additives that help to control drying time, increase weather resistance, and keep pigments uniformly spread in the paint solution.
Since it lacks heavy-duty additives, interior paint does not last long if used to paint the exterior of your home.Exterior paints are designed to withstand harsh weather conditions. Any of the chemicals used in these paints are strong enough to be harmful in enclosed indoor spaces. 

Limitations of interior paint used outside

  • Using an interior paint on an exterior surface, such as vinyl soft sheen paints, may cause a variety of issues. You’ll note right away that the paint itself may not be able to cling to the surface. 
  • Interior paints are often too thin for exterior surfaces, such as masonry. Many of these paints would take several coats to achieve even a thin coating.
  • In addition, this paint can often look patchy and unprofessional. It can also take a long time for these paints to dry. They would not be able to dry in humid or very cold conditions in certain situations. 
  • Paints for the interior do not use the same chemicals as paints for the exterior. They will not be immune to the impact of the weather, for example. Rain, frost, and other types of inclement weather can cause flaking, running, and cracking paint, among other problems.
  • Overexposure to the sun can trigger a variety of serious health issues in certain people.

Limitations of exterior paint used inside

  • External paints are designed to withstand the impact of the elements, but they are not intended for use inside. When used internally, they are easily labelled and scuffed. 
  • The fact that this paint can withstand the effects of the weather does not imply that it can withstand everyday use or footfall. 
  • They’re even more susceptible to cleaning’s impacts. You won’t be able to use household cleaning liquids if you spill food, for example. 
  • External paints do not look as good as internal paints, in addition to functional considerations. 
  • They’re less likely to cover the roof, wall, or floor entirely evenly. 
  • Some exterior paints emit potentially harmful fumes that dissipate when exposed to the elements. When used inside a house, however, these gases may become trapped, resulting in unpleasant odours.

Is it Possible to use Interior Paint Exterior?

There are a variety of reasons why you would want to use interior paint outdoors. Some of the reasons are as follows:

  1.  It’s less costly, you want to use up leftover paint, or you like the colour.
  2. Interior paints are brittle, lack the resin needed to adhere to external surfaces, and are more prone to cracking and flaking.
  3. If you insist on using interior paint outside, seal it with one or two coats of clear-coat sealer designed for outdoor use. It may prolong the time it adheres depending on the amount of exposure to the elements, but it won’t necessarily prevent it from fading, and the sealer may yellow.
  4. Using an interior paint with a sealer increases the amount of work required and reduces the cost of more costly exterior paints. Furthermore, using interior paint outside voids the warranty.
  5. Since the inside surface of a front door is shielded from the elements, it’s fine to paint it with interior grade paint. The floor, particularly if it’s a metal door, will need to be properly prepared. If the door is covered with a storm or glass door, you should use the same paint on the exterior; otherwise, it will fade, crack, and chip.
  6. Some people are unsure if interior paint can be used as an exterior primer. You may use it as a primer for a variety of reasons, including cost-cutting. To boost adhesion, it will need to be lightly scuffed with sandpaper and then painted with a better exterior paint of the same foundation.

What happens if you use interior paint outside by accident?

Accidents happen, whether you grabbed the wrong can of paint or didn’t realise there was a difference until it was too late. It’s not the end of the world if you use interior paint outside. The following will happen if you use interior paint to the exterior.

  1. It simply means that you’ll have to repaint the surface in two to five years rather than ten to fifteen.
  2. Interior paints are designed to protect the covered surfaces of a house, not to withstand the ravages of nature. It will fade faster and lacks the additives that protect against temperature extremes, UV rays, and mildew. You can either paint it over now with exterior paint or wait a year or two.
  3. You may as well finish the job if you’re almost finished. If it’s only just started, you can use exterior paint to cover it. Some people recommend sealing the interior paint with an expensive sealer and chalking it up as a lesson learned. Alternatively, instead of spending more money on a sealer, purchase a better exterior paint in the same colour and base and add another coat.

Can You Use Interior Paint Outside?

While an interior paint can theoretically be applied over exterior paint, it simply does not make sense. 

  • The absorption capacity will be low, most exterior paint is applied to exterior surfaces where interior paint fails, and the results will flake or peel after a few months. That’s a lot of time and cleanup work to get involved with later on, with little in the way of results. 
  • If the exterior paint is on furniture or an inside wall, however, a fresh coat of interior paint would suffice. However, to give the interior paint a proper “bed” to tie to and soak into, a primer layer must always be applied first.
  • Hybrid interior/exterior paints are now available from most paint manufacturers. These can be a smart way to get the most out of exterior paint’s longevity while avoiding health risks. They are usually more costly than paints intended for use inside or outside. 

You should think about it if you want the most long-lasting choice. It’s not the best choice if you’re looking for the most bang for your buck.

Read our articles on art and crafts.

Conclusion

Interior paint is specifically designed for indoor use and is ideally suited for that purpose. The paint can be used outside, but it won’t hold up to weather extremes and you’ll have to repaint earlier than expected. This article will help you understand interior paint, why it’s called interior, and what happens if it’s used outside.

Leave a Comment