Choosing the Right Paint: Interior vs Exterior

• Interior Paint: Designed for indoor use, it resists stains, is easy to clean, and has low VOC levels for better air quality. It's perfect for living spaces, kitchens, and bathrooms.
• Exterior Paint: Built to handle weather, it includes UV blockers, flexible resins, and moisture resistance. Ideal for outdoor walls, fences, and furniture.

Key Differences:

• Durability: Interior paint resists scuffs; exterior paint withstands weather.
• Resins: Harder resins indoors; flexible resins outdoors.
• VOC Levels: Lower for interiors, higher for exteriors.
• Finishes: More variety indoors; limited but tougher outdoors.

Quick Comparison:

Use this guide to choose the right paint for your project and avoid costly mistakes.

Main Differences: Interior vs Exterior Paint

Paint Materials and Strength

While interior and exterior paints share similar base ingredients, their formulas are designed to meet different performance demands.

Exterior paints are built to endure outdoor challenges with:

• Higher pigment levels for better UV protection and long-lasting color.
• Flexible resins that allow the paint to expand and contract with temperature changes, preventing cracks.
• Additives that resist moisture and other weather-related stressors.

Interior paints, on the other hand, focus on durability and aesthetics indoors:

• Hard resins that resist scratches and scuffs.
• Extenders that improve coverage and help control the sheen.
• Additives that make the paint easier to clean and more resistant to scrubbing and abrasion.

"For exterior paint the resin is flexible, so the paint can flex with heat expansion and contraction of materials outdoors without cracking. Interior paint doesn't need that flexibility, so it uses harder resins that make it tougher against marks and easy to clean." – COAT Paints

These differences not only affect how the paint performs but also influence safety and appearance.

Safety and VOC Levels

Indoor air quality can often have 2–5 times higher VOC (volatile organic compound) levels than outdoor air . This makes VOC content a critical factor when choosing paint, especially for interior use.

The British Coatings Federation categorizes VOC levels as follows:

• Trace: Less than 0.1%
• Minimal: 0.1–0.29%
• Low: 0.30–7.99%
• Medium: 8–24.99%
• High: 25–50%
• Very High: More than 50%

While safety standards are crucial, the choice of finish also plays a key role in both appearance and functionality.

Paint Finishes and Look

The finish you choose not only impacts the visual appeal but also determines how well the paint performs in its environment. Paint brands like Benjamin Moore provide a variety of finishes tailored for interior and exterior use.

Interior finishes typically include:

• Flat/Ultra Flat: 0–4% sheen (measured at 85°)
• Matte: 3–10% sheen (85°)
• Eggshell: 10–25% sheen (85°)
• Satin/Pearl: 20–35% sheen (60°)
• Semi-Gloss/Gloss: 40–65% sheen (60°)
• High Gloss: Over 85% sheen (60°)

Exterior finishes, designed for outdoor durability, are more limited:

• Flat: 0–3% sheen (85°)
• Low Lustre: 9–15% sheen (85°)
• Satin: 20–30% sheen (60°)
• High Gloss: Over 85% sheen (60°)

Each type of finish is chosen based on the desired look and the wear-and-tear the surface will face.

Interior Paint Uses

Where to Use Interior Paint

Interior paint is specifically made for indoor surfaces. For spaces like hallways and living rooms that see a lot of activity, a durable matte emulsion works best. Kitchens and bathrooms, on the other hand, need moisture-resistant paints to guard against mold and maintain their look over time.

Recommended Usage:

These suggestions align paint types with the unique needs of each space, ensuring the best performance for every area.

Interior Paint Benefits

Interior paints are crafted to meet the challenges of indoor spaces. Their specialized resin structure offers strong resistance to wear and tear while keeping VOC levels low for better air quality. Here’s why they stand out:

• Durability: Paints like Dulux Trade Diamond Matt can handle scuffs and stains with ease .
• Great Coverage: Professional-grade options often need just two coats for full coverage .
• Healthier Indoor Air: Low VOC formulations make them safer for indoor use .
• Ease of Use: Many modern paints are designed for simple application, perfect for DIY enthusiasts .

"The technical performance of this paint wow's me every time. There are so many products that address issues – it's amazing. Walls, cabinets, special primers, you name it, Benjamin Moore has it. This has saved me countless times from pure disaster." - House of Brinson

Common Interior Paint Types

Choosing the right type of interior paint ensures both functionality and safety. For fresh plaster, it’s recommended to start with a mist coat (a diluted version of the paint) before applying two full coats .

Here are some popular types of interior paint:

• Durable Matte Emulsion
  Perfect for high-traffic areas, offering resistance to water and wear.
• Acrylic-Based Paints
  Best for kitchens and bathrooms due to their resilience in humid conditions and ability to withstand cleaning.
• Specialty Paints (like Crown Clean Extreme)
  These are designed with features like antibacterial properties, anti-mold protection, and easy application, making them ideal for health-conscious and moisture-prone spaces .

Exterior Paint Uses

Where to Use Exterior Paint

Exterior paint is designed to shield outdoor surfaces from tough conditions like weather changes, moisture, and UV rays. Whether you're painting wood siding, masonry, metal, vinyl, or stucco, it's important to pick a product tailored for the material. For instance, Sherwin-Williams' Emerald® Rain Refresh™, introduced in March 2023, includes self-cleaning features to help surfaces stay clean and protected. To get the best results, aim for temperatures between 50°F and 85°F, with relative humidity levels of 40% to 70% during application . Painting during cooler times of the day can also aid in proper drying and adhesion . These specialized products make outdoor painting more effective.

Exterior Paint Advantages

Modern exterior paints bring several practical perks:

• Weather resistance: They protect surfaces from moisture, UV rays, and temperature changes .
• Cost savings: With an average exterior painting cost of $3,091, it can save you from repair bills that range from $2,622 to $20,492 caused by weather-related damage .
• Long-lasting: Over 70% of outdoor projects rely on acrylic latex paint due to its durability .

Main Exterior Paint Types

Choosing the right paint depends on your local climate:

A standout example is Sherwin-Williams' Emerald® Rain Refresh™ Exterior Acrylic Latex Paint, which helps surfaces stay cleaner by shedding dirt when it rains.

Experts suggest repainting every 5–7 years in hot climates and choosing paints based on the surface type and local weather conditions .

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What is the difference between interior and exterior paint?

Paint Selection Guide

Choosing paint requires balancing the condition of the surface, local weather challenges, and your budget.

Surface Type and Preparation

Before painting, assess and prepare the surface to ensure the best results. Different materials require different prep work:

• Wood: Sand the surface and prime any bare spots.
• Masonry: Clean thoroughly, repair cracks, and allow it to dry completely.
• Metal: Remove rust and apply a suitable primer.
• Previously painted surfaces: Clean and lightly sand to improve paint adhesion.

"A well-prepped surface is the foundation for a long-lasting and beautiful paint job"

Once the surface is ready, choose a paint that matches the specific environmental conditions.

Weather Considerations

The local climate plays a big role in how well paint performs over time. For areas with extreme temperature changes or coastal environments, look for paints designed to handle low temperatures or resist salt damage. For interiors, focus on formulas that address moisture issues or cater to your desired aesthetic .

Balancing Cost and Durability

After considering surface and climate factors, weigh the cost against the paint's longevity. Paint prices and performance vary widely.

For example:

• Armstead Contract Matt: Costs around £1.80 per liter and is a budget-friendly option.
• Benjamin Moore's Advance Waterborne Interior Alkyd: Priced at about £91.50 per gallon (3.79 L), it offers exceptional durability .

Economy paints save money upfront but may need more frequent touch-ups, while mid-range and premium options provide longer-lasting results.

"For the difference in price I'd say the quality is on par or better!"

"It's not the cheapest, but you get what you pay for and is definitely worth it in the long-run. I've used it throughout my own house because it has that look of a quality finish"

Paint Comparison Chart

The chart below highlights the main differences between interior and exterior paints, focusing on their features and best uses:

"Exterior paint has different additives to make it more hardy and resist cracking, fading and mould from harsher conditions outdoors." - Robert Abrahams, Author, COAT Paints

This table outlines the core contrasts between the two types of paint, helping you choose the right one for your project.

Conclusion: Paint Selection Tips

Choosing the right paint for your project doesn’t have to be complicated. For indoor spaces, look for paints with low VOC levels to ensure a safer environment. On the other hand, exterior surfaces demand paints with UV protection and mildew resistance, especially in areas like coastal regions where repainting might be needed every two years .

Higher-quality paints, priced between £25–£40 per liter, often provide better coverage and last longer . For interiors, opt for paints with harder resins to withstand wear and tear, while exteriors benefit from more flexible resins .

If you’re seeking guidance or quality products, Poppys.shop in Ton Pentre offers expert advice, a wide selection of paints, and convenient click-and-collect services. They also provide UK-wide shipping starting at just £2.97.

Keep in mind, using exterior paint indoors can be harmful due to its higher VOC content. If this happens, it’s essential to remove the paint and replace it with a suitable interior option . Making the right choice not only enhances the performance of your project but also protects your investment.

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