What is elastomeric exterior paint and is it a good choice for older masonry or stucco walls on New Brunswick homes?

Elastomeric paint is a thick, rubber-like exterior coating that stretches and contracts with building movement, making it an excellent choice for older masonry and stucco walls in New Brunswick's harsh freeze-thaw climate. This specialized paint can bridge hairline cracks and provides superior waterproofing compared to standard exterior paints.

What Makes Elastomeric Paint Different

Elastomeric coatings are much thicker than regular paint — typically applied at 10-20 mils thick compared to 2-4 mils for standard exterior paint. They contain high levels of acrylic resins that create a flexible, rubber-like membrane once cured. This flexibility allows the coating to stretch up to 300-500% without cracking, which is crucial for masonry and stucco that experiences significant thermal expansion and contraction during New Brunswick's temperature swings from -30°C winters to +30°C summers.

The thick application also provides excellent waterproofing. While regular paint allows some moisture penetration, properly applied elastomeric paint creates a nearly impermeable barrier that prevents water from entering the substrate. This is particularly valuable for older masonry homes in Saint John, Fredericton, and Moncton where the original mortar joints may be deteriorating and allowing moisture entry.

Why It Works Well for NB's Older Homes

New Brunswick has thousands of older brick, stone, and stucco homes built between 1900-1960, particularly in the historic areas of Saint John's uptown, Fredericton's downtown core, and older Moncton neighbourhoods. These buildings commonly develop hairline cracks in stucco or mortar joints due to settling, freeze-thaw cycles, and normal aging. Traditional paint simply bridges over these cracks temporarily — when the building moves, the paint cracks and water enters.

Elastomeric paint moves with the building. When a hairline crack opens during winter contraction, the elastomeric coating stretches across the gap. When the building expands in summer heat, the coating compresses back. This flexibility prevents the coating from failing and maintains the waterproof seal year-round.

The Maritime climate's high humidity and frequent rain make waterproofing especially critical. Older masonry that allows water penetration can suffer rapid deterioration during freeze-thaw cycles — water enters, freezes, expands, and spalls off pieces of brick or stone. Elastomeric paint's superior moisture barrier helps prevent this damage.

Application Considerations for NB

Elastomeric paint requires careful surface preparation and proper application timing. The substrate must be completely clean and dry — any loose mortar, efflorescence (white salt deposits), or peeling paint must be removed. Power washing followed by at least 48 hours of dry weather is typically necessary before application.

Temperature and humidity requirements are stricter than regular paint. Most elastomeric coatings need temperatures between 10-30°C and relative humidity below 70% during application and initial cure. In New Brunswick's humid summers, this often means starting early morning and stopping by mid-afternoon. The thick application also means longer drying times — plan for 4-6 hours between coats in ideal conditions, longer in high humidity.

Cost and Longevity

Elastomeric paint costs significantly more than standard exterior paint — expect $70-120 per gallon compared to $55-80 for premium acrylic latex. However, the coverage rate is different due to the thick application. One gallon typically covers 100-150 square feet (compared to 350-400 sq ft for regular paint), so material costs per square foot are roughly 3-4 times higher.

The payoff comes in longevity and performance. A quality elastomeric coating should last 10-15 years on masonry in New Brunswick's climate, compared to 5-8 years for standard exterior paint. The superior waterproofing also protects the underlying masonry from expensive freeze-thaw damage.

When to Hire a Professional

While DIY application is possible on single-storey buildings, elastomeric paint's thick consistency and specific application requirements make professional application advisable for most projects. The paint must be applied evenly at the correct thickness — too thin and you lose the flexibility benefits, too thick and it may not cure properly. Professional painters have spray equipment designed for heavy-bodied coatings and experience achieving the proper mil thickness.

For older masonry homes with significant height or complex architectural details, professional application is strongly recommended. The investment in proper application pays dividends in coating performance and building protection.

Need help finding a professional painter experienced with elastomeric coatings? New Brunswick Painting can match you with contractors familiar with masonry restoration and specialty coatings for your heritage home project.