Are you wondering if you can use paint meant for exterior surfaces indoors or even the other way round? There may be several reasons why you’d want to use paint meant for exterior surfaces indoors.
For example, you may have some leftover exterior paint and your kitchen or bathroom looks like it could use some new paint. The thought of saving a little cash and getting the project done is quite a tempting one. But should you do it?
Technically, you can use paint meant for exterior surfaces to paint the interior surfaces and vice versa. However, there are a number of reasons why we don’t recommend you do as we will discuss later in this article. But for you to appreciate that, let’s begin by discussing the types of paints used for exteriors and interiors.
Types of paints
Interior and exterior paints are formulated differently and therefore have different properties that make them adhere to the intended surfaces.
- Interior paint
The most common type of paint used to paint interiors is acrylic latex. However, it doesn’t contain latex. This paint is water-soluble when wet, has very little to no order, and emits very minimal amounts of volatile organic compounds. In addition, most interior paint is formulated to be washable. It is also scratch-resistant. These properties make the use of interior paint more comfortable especially in living spaces.
- Exterior paint
The most common type of exterior paint is also acrylic latex. It has some of the properties of interior paint like being water-soluble when wet. The major difference with exterior paint is that it has added resin which makes it weather resistant. For this reason, exterior paint easily works on a number of surfaces such as stucco, fiber cement, bricks, and wood siding.
Can You Use Exterior Paint Indoors?
As we have already observed, exterior paint is formulated to withstand various weather conditions including intense heat, Sunlight, rain and even freezing temperatures. The resins added to the exterior paint make it expand or contract instead of cracking depending on the weather conditions.
Additionally, exterior paint contains extra additives that deter fading, mildew, and staining even after being exposed to mineral-rich water. These properties make exterior paint durable in addition to the fact that it also comes in a variety of colors.
It is therefore understandable that any homeowner may be tempted to have these properties on indoor surfaces. However, our advice is don’t. While exterior paint will easily dry indoors and last much longer, here are our top reasons why you should never use exterior paint indoors:
- The additives used in the formulation of exterior paint to make it extra resilient to weather conditions are not intended for indoor use. Using the intense levels of resins of exterior paint indoors will affect air quality and thus pose serious health issues to members of the household. This will cost more than the savings one could have gotten by using the paint indoors.
- The acrylic latex paint that has been formulated for outdoor use contains high amounts of volatile organic compounds (VOCs) than the amounts you’d expect in acrylic paint formulated for indoor use. This, therefore, means that to use it indoors will be exposing yourself and others to smelly and hazardous respiratory conditions. This is more especially for people with breathing difficulties, allergies, and chemical sensitivities. Moreover, exterior acrylic latex paint will continue to emit VOCs even after drying and thus continually exposing people to ill health.
- The additives used in exterior paint to prevent mildew will likely cause strong odors and even adverse allergic reactions when used indoors. This will make indoors not only unsafe but also much less comfortable to be in.
- Enamel or oil-based paints produce toxic fumes. In most jurisdictions, it is illegal to use them indoors and even outdoors. In addition, they contain high amounts of VOCs that vaporize and are a leading cause of the accelerated depletion of the ozone layer. Their adverse contribution to climate has seen them being banned by most regulatory bodies across the globe.
- Although exterior paint is quite durable outdoors, it doesn’t perform quite as well indoors. The conditions inside make it more prone to scratches and scuffing.
Can You Use Interior Paint Outdoors?
Technically you can be able to use interior paint outdoors. Interior paint doesn’t pose any health issues when used indoors and outdoors. However, using interior paint outdoors is not a good investment and thus we don’t recommend the same as well. Here is why:
- What makes exterior paint withstand extreme weather conditions outdoors are the added resins, fungicides, and other additives. Unfortunately, these are not to be found in interior paint. As a result, interior paint won’t stand up long against weather elements and thus makes no sense why you’d want to use it outdoors.
- Interior paint does not have the formulation that allows it to expand and contract depending on the weather conditions. As thus, when exposed to extreme heat or freezing temperatures outside, Interior paint will likely crack.
- Interior paint has not been formulated to be exposed to direct sunlight. As such once applied, it will fade out quite faster when exposed to direct sunlight.
While you may be tempted to use exterior paint indoors and vice versa, this will not be a wise decision to carry out. Paint manufacturers labor painstakingly to formulate paints that will work on particular surfaces while also considering other implications such as durability, and the health of the users. Contra use of the paint will therefore pose serious health challenges to the user or be a poor investment. None of this is attractive. We, therefore, recommend that you only use exterior paint outdoors and interior paint indoors. Continue checking our site for more tips and insights on painting and paints.