The difference between interior vs exterior paint is in the formulation. Interior paints need to be durable and scrubbable for easy cleaning within your home. In contrast, exterior paints need weather resistance and protection against UV rays to maintain long-term coverage on the outside of your home. Fortunately, Real Milk Paint bridges the gap when you mix it with Outdoor Additive to create versatile interior and exterior paint.
The Differences Between Interior and Exterior Paints
Most paints contain the same main components: pigment, resin, solvents and additives. For example, oil paint manufacturers typically use mineral spirits as a solvent, while latex paint manufacturers use water. The main difference between interior and exterior paint, however, comes down to the binding resins. The binding resin in exterior paint is softer to better resist fading, peeling and chipping. In contrast, the resin in interior paint is more rigid to reduce smearing and scuffing.
Interior Paint: Composition, Properties and Characteristics
Even though interior paint is more delicate than exterior paint, it holds its own regarding volatile organic compounds (VOCs). Indoor paint typically has much lower VOC concentrations, and some paints, including Real Milk Paint, have no VOCs at all, so you can paint indoors without worrying about needing extra ventilation. Likewise, water-soluble interior paints typically don’t contain fungicides and offer a more comprehensive selection of finishes, from matte and satin to gloss and semi-gloss, than their exterior paint counterparts.
While exterior paint colors are basic, interior paint colors run the gamut from soft and subtle to bold and bright. Organic pigments in indoor paints such as Real Milk Paint and all-natural ingredients, including milk casein and lime, provide versatile colors that are safe for use in homes with kids and pets. Many indoor paints are also stain-resistant for easier cleaning. Keep in mind that while you can use exterior paint indoors, it requires more ventilation and drying time to cure. Even without exposure to sunlight, most interior paint dries quickly.
Exterior Paint: Composition, Properties and Characteristics
Exterior paint is specifically formulated for outdoor environments because it must handle extreme temperatures and be flexible enough to withstand significant temperature changes when warm weather suddenly becomes cold. The binding resins within exterior paints let the coverage expand and contract without peeling and chipping. Additionally, additives help it resist staining, mildew and fading. You can even combine interior paint with Outdoor Additive by The Real Milk Paint Co. to transform it into a durable exterior paint.
Another difference between interior and exterior paint is adherence. Outdoor paint has a formulation that promotes better coverage on rougher surfaces. Unfortunately, snow-, rain- and fade-resistant exterior paints usually contain more VOCs than interior paints, so you don’t want to use exterior paints inside except in highly ventilated areas. On the bright side, oil-based paint manufacturers are phasing out this type of paint due to the higher VOC emissions.
Lastly, outdoor paint comes only in flat, gloss or semi-gloss enamels, so you only have a few options when choosing paint colors for outdoor surfaces.
How Application Differs Between Interior and Exterior Paints
Painting techniques differ depending on whether you’re using interior or exterior paint. Different surfaces also have their own requirements. Many exterior paint jobs require scraping away old paint before the application process can even begin.
Techniques for Using Interior Paints
When you’re painting an indoor surface, the process is relatively straightforward. First, clean the interior walls or fixtures you wish to paint, use painter’s tape to cordon off areas that don’t need coverage, then mix your interior paint colors. If you’re using Real Milk Paint, it comes in a powdered form that you mix at a 1:1 ratio with water. Other water-soluble interior paints may require stirring before use. If you have any holes or cracks to repair, now is the best time. If you plan on using milk paint, we recommend not using color changing fillers.
Now, you’re ready to start painting with your choice of a roller or brush, depending on the size of the area. For instance, a small paintbrush may be fine for the project if you’re painting interior cabinet surfaces. Larger interior painting projects such as sprucing up gallery walls or a whole room makeover may require a long roller for application or even a paint sprayer.
No matter how you cover the main area with interior paint, however, the edges need the detailed touch of a brush, as do any touch-ups you might need to perform. After coating the interior surfaces, let them dry a bit, then add a second coat of color. Most interior paints only require two coats for satisfying finished results.
Techniques for Using Exterior Paints
The first step of using exterior paint is determining whether you need to remove an old paint layer. For instance, if the house is old and may have lead paint, you can put down a drop cloth and scrape it all away or let our Soy Gel Professional Paint Remover do the work for you. Next, clean up the scrapings and wash the exterior surfaces with a cleaning product that removes mildew. If you find any rough spots as you go, sand them down or repair them with Real Wood Filler.
Now, you’re ready to paint. First, apply primer to the outdoor surfaces to ensure the paint colors stay put, or if you’re painting in raw wood, use Real Milk Paint with Outdoor Additive mixed in for paint you don’t need to prime. Next, caulk all the joints for extra weather resistance. Once this dries, tape off areas you don’t want to cover and mix your paint. Roll exterior paint onto larger areas and use a high-quality paintbrush to get into smaller spaces.
Remember that the higher the gloss levels of exterior paint, the more durable it is. That means you need additives when you want to use non-glossy paint for painting the outside of your home. Latex and milk paints are the best choices for home exteriors because they hold up well in most climates, dry quickly and enable easy soap-and-water cleanup.
As the last step, add a top coat to protect your paint job. Latex paints fare well with a polyurethane top coat, while Real Milk Paint seals perfectly with Outdoor Defense Oil for a nontoxic remodel.
Factors to Consider When Choosing Interior and Exterior Paint
The most important factor to consider when choosing interior and exterior paint is where you plan to use the product. Since these products are formulated differently, you want the one with superior staying power for your project. For instance, choose paints with more pigment if you want a highly vibrant gallery wall. Likewise, if you want a solution for exterior painting that doesn’t contain VOCs and other chemicals with the potential to harm, you can select a top-notch milk paint such as Real Milk Paint that bonds well on outside surfaces when you mix in Outdoor Additive and seal it with Outdoor Defense Oil.
Start Your Next Painting Project With Real Milk Paint
When you need versatility and dependability in a nontoxic paint that’s safe for food-contact surfaces, look to The Real Milk Paint Co. Our VOC-free paints work equally well as interior or exterior paint by mixing in Outdoor Additive, so you can match up your interior paint with exterior paint products that last. Check out our vast collection of all-natural milk paints to find options that uplift the look of your home and DIY projects.