Both exterior and interior paints are critical in maintaining the good look of a house. The exterior paint will tell the visitor what to expect once they get inside the house.
On the other hand, the interior allows the visitor to relax and enjoy the stay in the house. So the two types of paints are different, and so you may not substitute one for another.
The difference between the interior and exterior paints lies in the resin used to manufacture the paint. This is a component that binds the paint’s pigment to the materials or substrate. The pigments in the exterior paint are strong and resistant to temperature variations and moisture.
So if you do not understand the paint pigments, you may be wondering whether you can use the interior paint on the outside and vice versa. Of course, you can, but the results you get will tell you that it is not the best thing to do.
The exterior paint is designed to resist and withstand mildew, UV, wind, and snow. Also, it should be able to withstand extreme temperatures and mildew.
Read on to understand the difference between interior and exterior paint.
The interior paint has fewer binding resins and pigments. So it may not be the correct paint to use on exterior surfaces. As such, it may not be a good idea to use the living room leftover paint to repaint an exterior door or wall.
Most interior paints cannot withstand harsh environmental conditions like mildew, UV, wind, and snow, and they may also not withstand extreme temperature and snow. If used on such surfaces, it flakes, fades, and crack.
The interior paints are formulated for indoor use only, and they are meant to adhere to indoor surfaces and absorb and reflect light depending on the prevailing weather conditions. The paints are not designed to withstand the contraction and expansion of the freeze-thaw.
Also, they cannot withstand extreme weather conditions.
Typically, most paints feature four parts, the binders, the pigments, additives, and liquid. But it is the pigments and the additives that make the exterior paint different from the interior paints.
The interior paints have lower volatile organic compounds to reduce exposure to the risk associated with off-gassing. VOC helps to stop liquids from vaporizing, and they allow the paint to harden as soon as you finish the job.
On the other hand, interior paints can be water-based or oil-based. Oil and water offer different adhesives and properties. Therefore, you may choose one depending on the goal you want to achieve.
Interior paints do not need to deal with changing or harsh weather environmental conditions. So they have low temperature and water resistance ability.
Besides, these paints fade fast when struck by the sunlight. But this is not the case for exterior paints, which are made to withstand all weather conditions.
Interior paint may not withstand extreme temperature and UV. Also, when used, they give a more porous finish. Thus, the paint will either fade or crack. Also, it may change to chalk or powder. Also, they crack and flake more quickly.
As such, it may not be of use when used as outdoor paint. Also, the finish may be too porous, which makes the paint fade fast.
Of course, there are temptations to try to use the interior paint outside because it is cheap. Some people may want to use it because they like the color.
But using the paint on the outside does not add value to your home.
The paint is not freeze-thaw; it will fade, crack and break down faster. Also, the paint is porous and lacks the resin needed to bind it to the exterior surfaces.
What’s more, is that the paint is likely to flake and crack. Further, it hardens and protects it from elements that may weaken and reduce the time it adheres on surfaces.
But you can use the interior paint on interior walls, slabs, and concrete. All you need to do is carry out some prep work like cleaning the surfaces, filling the cracks, and using sealers.
Also, using interior paint on exterior surfaces may require that you give it an additional coat to reduce exposure to sunlight and other adverse weather effects.
Interior paints may be water-based or oil-based. These paints have different adhesive properties that range from semi-gloss to flat to a high gloss.
You can choose to paint over water-based and oil-based after applying the stain block sealer or primer. Also, you can decide to apply oil-based paints over the oil-based paints after they dry. But to do this, you will need to scuff the glossy surface with some piece of sandpaper.
Water-based paints have binders and pigments that make them blend with water. The water behaves like a carrier and will evaporate to leave the color on the surface.
Such latex-painted surfaces hold the color better, and cleaning them is easier. Water paints contain fewer VOCs, and so they are friendly compared to oil paints.
Also, when the paints are dry, the surface becomes flexible and durable. Such paint can be applied on ceilings, walls, and other surfaces.
Also, cleaning the brushes is easy, and it is easy to remove the spills using soap and water.
On the other hand, oil-based paints are loaded with natural oils such as soybean, Tung, and linseed. They also contain synthetic alkyds, pigments, and some solvents thinner.
When you spread the oil on the surface, the thinner will evaporate to leave behind pigments and resin that forms a long-lasting hard coat.
The trouble with oil-based paints is that they contain more VOCs. Therefore, they are not environmentally friendly. Also, the surfaces are hard to clean, so that the paint will work well on the baseboard, trim, and doors.
Note that the oils will take a longer time to dry, but when they do, it creates a hard film that is tough and durable. Also, cleaning up brushes and spills is difficult and may require that you use stronger solvents like turpentine, mineral spirits, and thinners.
Both water and oil-based paints contain ingredients that work in the same way. For instance, the oil and water spread the color pigments and bind them on surfaces before they evaporate.
They also contain different additives depending on the use to which they are put.
The paints contain fillers such as barite, lime, and talc that help to make the paint thick. They also contain bonding additives that help to make the paint stick on the surfaces on which they are applied.
Besides, paints contain enamel to make them less porous, harder when dry, and durable.
Conditioners- they help improve the flow of the paints and reduce drag. Also, they improve the ability to level the paint on surfaces and reduce brush drag.
Texture additives- these are things like fine sand which make painted surfaces less slippery.
Glitters – are important ingredients that help to enhance the reflective properties of surfaces.
Scents- they are added to give the paint some good smell
Pigments- they are the important ingredients that provide the paint with its color. Such pigments may be inorganic or organic and determine how durable the color will be.
It also determines how often the color needs to be repainted.