What Is Elastomeric Paint and Should You Use It Outside?

Cracks in stucco. Water intrusion through concrete walls. Paint that flakes and fails after just a few seasons. If these issues sound familiar, elastomeric exterior house paint might seem like the answer. But is it really the right solution for your home?

This blog cuts through the marketing and explains what elastomeric paint is, where it excels, where it fails, and why professional application matters.

What Is Elastomeric Paint?

Elastomeric paint is a high-build, rubber-like coating engineered to stretch and return to its original form. It’s formulated from 100% acrylic or acrylic-modified polymers, making it ideal for masonry, stucco, and other porous or crack-prone exterior surfaces.

Unlike traditional latex paint, which dries at a thickness of 1.5–2.5 mils per coat, elastomeric paint typically dries at 10–20 mils for a single application and up to 40 mils with two coats.

Key Characteristics:

Where It Performs Best

Elastomeric paint is not a general-use coating. It’s a specialty product designed for specific exterior surfaces:

Recommended Substrates:

• Stucco (traditional and synthetic)

• Concrete (poured or tilt-up)

• Concrete masonry units (CMU/block)

• Brick (after proper prep)

• Fiber cement (only with manufacturer approval)

Avoid Using On:

• Wood siding or trim

• Previously painted surfaces with moisture problems

• Surfaces where high vapor permeability is required

Elastomeric vs. Traditional Paint: A Side-by-Side Comparison

Leading Elastomeric Paint Brands and Products

Here are some industry-standard products that professionals rely on:

Tip: Always check the product’s Technical Data Sheet (TDS) for substrate compatibility, required primers, and curing conditions.

Proper Application Process: Step-by-Step

Elastomeric paint must be applied correctly to perform as advertised. Most manufacturers recommend two coats at a minimum dry film thickness of 20–40 mils.

Step 1: Surface Inspection

• Test moisture content using a digital moisture meter (<12% is ideal).

• Check for structural cracks or efflorescence.

• Clean mildew, chalking, or dirt thoroughly.

Step 2: Surface Preparation

• Pressure wash to remove all debris and contaminants.

• Patch and seal cracks with elastomeric caulk rated for expansion.

• Allow surfaces to dry 48–72 hours before priming.

Step 3: Priming (If Required)

• Use a masonry primer or bonding primer based on surface.

• Example: Sherwin-Williams Loxon Conditioner for chalky surfaces.

Step 4: Application

• Airless sprayer with a 0.021–0.027 tip is standard.

• Roller with 1–1.25″ nap is acceptable for textured walls.

• Apply two uniform coats, each at 10–20 mils wet film thickness.

• Avoid over-brushing or thinning the product.

Step 5: Dry and Cure

• Allow 24–48 hours between coats.

• Full cure time: 7–14 days depending on temperature and humidity.

Coverage and Cost Considerations

Coverage:

• A gallon of elastomeric paint covers 75–125 sq. ft., about half that of standard paint.

Cost Estimate:

Common Mistakes to Avoid

Applying elastomeric paint improperly can cause premature failure. These are some of the most common and costly mistakes homeowners and inexperienced painters make:

Top Mistakes:

• Applying over a damp surface — traps moisture and causes blistering

• Skipping primer — reduces adhesion, especially on chalky or porous walls

• Insufficient film thickness — too thin and the paint won’t flex or waterproof

• Wrong tools — low-quality rollers or thin brushes won’t spread the paint evenly

• Applying in cold or wet conditions — elastomerics need heat and dry air to cure

Tips for Success

• Use a wet mil gauge to check film thickness during application.

• Work in manageable sections—the product dries quickly and can create seams if overlapped poorly.

• Inspect for trapped moisture before sealing the surface. If in doubt, wait longer.

• Always follow the manufacturer’s TDS and application instructions.

Is Elastomeric Paint Breathable?

Elastomeric paint’s low permeability is both a strength and a liability.

Pros:

• Prevents water penetration from the outside (rain, snow)

• Ideal for flood-prone or humid regions

Cons:

• Traps water vapor inside walls if they’re not fully dry before application

• Not ideal for older homes without vapor barriers or for use over wood siding

Some brands now offer “breathable” elastomeric coatings, like Benjamin Moore Ultra Spec Masonry Elasto, which allow limited moisture vapor to escape.

Always look for the Perm Rating on the TDS:

• <1: vapor barrier (not breathable)

• 1–10: semi-permeable (partially breathable)

• >10: permeable

When to Use vs. When to Avoid

Use Elastomeric Paint If:

• Your exterior walls are made of stucco, CMU, concrete, or brick

• You’re repairing minor cracks or sealing porous masonry

• You want a long-term waterproof membrane (10–15 years)

• You live in a humid, wet, or high-UV climate

Avoid If:

• Your walls are wood, metal, or have poor ventilation

• Moisture is present inside or behind your exterior surface

• You’re repainting over old layers without full removal

• You’re not using a professional with experience in elastomeric systems

Why Professional Application Is Critical

Elastomeric paint is not forgiving. Missteps in preparation or application can void warranties and lead to bubbling, peeling, or mold growth.

Why Hire a Pro:

• Moisture testing tools like infrared cameras or meters

• Access to commercial-grade primers, sprayers, and coatings

• Experience applying uniform mil thickness for long-term performance

• Manufacturer-trained teams who understand each product’s behavior

Professional painters often back their work with 5–10 year warranties when using elastomeric systems. DIY jobs carry all the risk.

Think Long-Term, Not Short-Term

Elastomeric exterior house paint isn’t cheap—but when applied correctly, it can protect your home for 10–15 years or more. It seals hairline cracks, prevents water damage, and withstands the harshest weather. However, it must be used in the right context and installed with precision.

If you’re dealing with failing stucco, porous block, or a leaky concrete façade, elastomeric might be your best solution—but it’s not a DIY project. A skilled professional will assess your surfaces, recommend the right primer and product, and apply it to specification.

Ready to Seal and Protect Your Home?

Contact us today for a free exterior painting estimate. We’ll help you determine if elastomeric paint is right for your home—and ensure it’s applied to last.