What is Interior Paint and Can it Be Used Outside?

Typical paint which is used for the interior of a building tends to be one of four main finish types, which are:

  • Emulsion – used for walls and ceilings, comes in matt, silk, or mid-sheen finishes.
  • Gloss – used on woodwork or metal detailing, a smooth and shiny finish.
  • Eggshell – used on woodwork or walls, a mid-sheen finish which is also smooth.
  • Satin – used on woodwork typically, this paint finish is semi-shiny and not too dissimilar to the eggshell but softer and less brittle.

Within these categories, you’ll find that there are further sub-divisions, which give reference to how the paint is created; this can be a handy reference, especially when seeking out less stinky paints:

Water-based; as the name suggests, this paint type is water mixed with pigments and binders, with the lowest V.O.C content. Brushes and rollers are easily cleaned with water. Widely used and dry quickly.

Oil-based; thicker, and trickier to work with, the oil base gives off a stronger odor that hangs around for a while whilst it off-gases. You’ll need brush cleaner or white spirit to clean equipment with; once the common choice for woodwork paints, they can take a couple of days to harden fully.

Alkyd-based; this range of paints does not rely on water or oil bases; instead, it is just a blend of chemicals. The modern version of traditional oil-based paints, this synthetic surface coating is still a bit on the pongy side and has V.O.C. to contend with.

Shellac-based; commonly used as a primer, stain block, or base, it’s a resinous, waxy paint that is notoriously tricky to apply nicely, and brushes are also hard to clean. High on V.O.C’s, this will dry quickly, but the smell remains.

Armed with this knowledge, it should make more sense when selecting a paint for your project.

Now, this isn’t to say that these paints don’t get used elsewhere; we all know someone that likes to throw the rule book out and do as they please, despite being advised not to, you may even be one yourself?!

However, when it comes to painting and decorating, there is usually a reason that the guidelines are there, to begin with.

What is Interior Paint Used For?

Interior paint is used for making your interior spaces look nice, being able to change the feel of a room almost instantly as decorating is a very transformational trade.

Being able to do so is essential when you’ve recently moved in, and the decor isn’t to your tastes, or has become tired over the years and is in need of a freshen-up.

In a relatively short space of time, you can make a room or house much more appealing to spend time in.

Painting is usually relatively cost-effective, especially in comparison to wallpapering or the installation of more specialized surface coatings such as Venetian Plaster. 

Interior paint can be used to coat all manner of surfaces from walls and ceilings, to woodwork and metal components, through to tiles, cupboards, and worktops.

The key is finding the right paint for the application at hand.

Can I Use Interior Paint Outside?

This is the golden question! 

As we touched on at the beginning, yes, you can; however, it’s not generally advisable, and for the sake of doing things correctly, then get back down to the paint shop and buy the suitable paints.

Certain instances, such as painting areas that are undercover, either fully or partially, have some protection against the elements, or if the paint jobs are only required to look good for a number of hours or days, then you use consider interior paint over exterior one.

Alas, there is not a concise one size fits all approach here, as there are quite a few variables to consider.

Questions that can be useful and aid you in making a judgment call include:

  • Will the area be completely exposed or undercover and outside?
  • What material is being painted?
  • What is the condition of the surface currently which is planned to be painted?
  • Do you know what type of paint was last used there?
  • Is the paint required to last a short time as a quick freshen-up, or do you plan for it to last a long time, a number of years?

Also, whereabouts in the world or country are the planned works?

Exterior environments around the globe present their own set of challenges for us.

Once you’re clear on the above points, we can look at each type of interior paint individually.

Interior paints have been explicitly designed to be used inside, below are the key points:

  • Low V.O.C.’s (Volatile Organic Compounds).
  • Formulated for interior use.
  • Don’t contain unique U.V. pigments, binders, or additives to help weatherproof.
  • Not tested to withstand being exposed to the elements.

When looking to paint over a previously decorated area, you’ll need to consider what paint was used before and prepare accordingly; certain types of paint won’t adhere to the surface underneath very well.

An example is painting vinyl matt emulsion over a previously oil-based gloss finish.

Or water-based satin over the top of the shellac base coat.

As these paints aren’t designed to do so, you may need to use a special primer to get the paint to grip or select an alternative coating.

Sanding down, taping up, and ensuring surfaces are in good condition and ready to paint are also a couple of tips; if you need further insight to correct surface preparation, check out YouTube or a preferred platform where you’ll find plenty of tutorials.


It has been said that ‘preparation is the key to decoration’.

No matter how good you paint or the technique used to apply it, if the surface underneath is not in great shape or hasn’t been prepared, the finish will not be good.

You’ll also be setting yourself up for future problems; paint can crack, peel, flake, or deteriorate at a quicker rate.

This is a general rule and will apply to the interior or exterior painting.

Interesting Related Article: “Tips for budget-friendly home renovation