Can I use the same paint for Interior & Exterior Painting?

You may be wondering, is there anything different between interior and exterior paints? Are they not all paints? And, can I use the same paint for interior and exterior painting?

Well, you're not the only one asking such questions. And this blog post serves to clarify things.

Notably, interior paints should not be used for exterior painting, and neither should exterior paints be used for interior painting. While interior paints are manufactured to enable cleaning and prevent staining, exterior paint is made to withstand the harsh weather conditions outside. Their purpose makes their chemical compositions different.

However, to better understand the differences between interior and exterior paints, let's get to know a thing or two about paints.

Paint chemistry

All paints, including interior and exterior, contain resins, pigments, solvents, and additives. The solvent is the solution in which everything else is immersed, and it's what gives paint its liquid or semi-liquid state. For latex paint, the solvent is water. In oil-based paints, the solvent is mineral spirits. When the paint dries up, the solvent goes into the atmosphere, and the resins, pigment, and additives remain. The pigment is the paint's color, and the resin binds it to the surface. Acrylic and epoxy are some typical examples of resins. On the other hand, additives give the paint additional properties, such as preventing mildew growth and making the dried paint washable.

Both interior and exterior paints can have the same solvents, although oil-based paint. We've seen the similarities. What then are the differences?