Why Shouldn’t You Use Exterior Paint Inside and Vice-Versa
A fresh coat of paint is one of the easiest and most affordable ways to instantly upgrade any home, property, or space. But as straightforward as painting might seem, choosing the wrong type of paint for the job can lead to costly and even unhealthy consequences.
That’s why many homeowners turn to interior painting Dunedin professionals when tackling indoor and outdoor projects. Property owners in Otago count on Three60 Painting to provide high-quality and lasting paint jobs in the face of salty coastal air and unpredictable weather patterns. Our team of painters understand the difference between interior and exterior paint, and we can help you keep your home protected and looking its best for years to come. However, it’s also important for homeowners like you to know why we make it a point to use exterior paint outside of your home and keep interior paint safe from the elements. Here’s a list of reasons why you should insist on doing the same no matter who handles your paint jobs:
Exterior Paint Contains High VOC Levels That Are Like a Cloud of Chemicals You Can’t Escape
One of the biggest reasons to keep exterior paint outside is its high content of volatile organic compounds, or VOCs. These compounds are released as the paint dries and evaporates, and they’re what give fresh paint that sharp, chemical smell. Outdoors, VOCs are far less of a concern because they dissipate into the air quickly, especially on a breezy Otago afternoon. But indoors, those fumes hang around much longer.
Exterior Paint Has Strong Odours and Slow Curing
Alongside high VOCs, exterior paints also tend to have more persistent and unpleasant odours. These aren’t the kind of smells that a scented candle or a few hours of open windows will fix. In fact, the scent can linger for days or even weeks, depending on the airflow and room temperature. And if you live in Dunedin, where wintertime ventilation is limited and heaters are working overtime, the paint might take even longer to cure.
Unlike interior paints that are formulated to dry quickly and evenly in room-temperature conditions, exterior paints are built to cure slowly under sunlight and fresh air. When used indoors, they may remain tacky or soft for an extended period, which can affect both the look and feel of your walls. It also increases the chance of paint smudges, furniture stains, or accidental transfer if you touch the walls before they’ve fully cured.
There Are Health Risks When Exterior Paint Is Used Inside
Beyond the discomfort of a lingering odour or sticky walls, there are legitimate health concerns when using exterior paint inside. High levels of VOCs and chemical additives are linked to a range of side effects, especially with prolonged exposure. People may experience symptoms like nausea, fatigue, or even breathing issues, and that’s without underlying conditions like asthma or allergies in the mix. Children, elderly people, and pets are particularly vulnerable to these effects.
While it might seem like a harmless shortcut, painting your kitchen or lounge with exterior paint could turn your safe haven into an irritant-filled space. If you wouldn’t use outdoor sealant on your dining table, you probably shouldn’t use exterior paint on your walls either.
Interior Paint Has Poor Durability
Applying interior paint to exterior surfaces might seem like a clever way to use up that half-full tin, but this can end up costing you more in the long run. Interior paint simply lacks the elasticity and toughness to expand and contract with shifting outdoor temperatures. As a result, it tends to crack, chip, or flake far sooner than exterior-grade paint.
If you paint your shed or deck furniture with indoor paint, you may find yourself repainting far more frequently or stripping it all off and starting from scratch. And let’s be honest, nobody wants to waste their summer weekends sanding off peeling paint just because they tried to cut corners.
Mould and Mildew May Grow When Interior Paint Is Used Outdoors
Otago’s cool and sometimes damp climate is a paradise for mould and mildew, especially in shaded or moisture-prone areas. Unlike exterior paints, which contain mildewcides and moisture-resistant additives, interior paints aren’t equipped to defend against biological growth. Once exposed to rain, dew, or condensation, they soak up moisture like a sponge, which creates the perfect conditions for black spots and green patches to take hold.
Even if it looks okay initially, untreated timber or weatherboards painted with interior paint will eventually absorb water, soften, and rot. And cleaning up mould from the surface of compromised paint isn’t just a matter of wiping it off; it often requires sanding, resealing, or even replacing the underlying materials.
At the end of the day, using the wrong type of paint for the job can lead to issues over time that are simply not worth it. The differences between interior and exterior paints aren’t just about labels or price tags; they’re about how each formula is designed to handle specific conditions.
So whether you’re brightening up your lounge or weatherproofing your deck in Dunedin’s unpredictable climate, make sure you’re using the right paint for the space. And if you’re unsure or want to ensure a top-quality, long-lasting finish, don’t hesitate to call in the professionals. Hiring experienced painters from Three60 Painting can take the guesswork out of the process, saving you time, stress, and costly do-overs.