As a plastering contractor, your craft involves more than just creating visually appealing surfaces. While attractive stucco and plasterwork is your hallmark, there’s an equally critical aspect that often is not within your work scope and remains unseen but is paramount for cladding performance: weatherproofing. In conjunction with proper flashing techniques, water-resistive barriers play a pivotal role in ensuring the longevity and performance of exterior cladding systems. Let’s explore why weatherproofing matters and how it directly impacts your work.

Plaster around a new window installation
New windows surrounded by a weatherproofing layer
An open door surrounded by weatherproofing
Scaffolding around a building project
A weather resistant barrier

The Role of Water-Resistive Barriers

WRBs serve as the unsung heroes of wall assemblies. These protective layers are the primary protection against forces of nature, safeguarding against moisture infiltration and, in many instances, air leakage. Here’s why they are paramount for plastering contractors:

1. Moisture Management: Moisture is a silent adversary that can compromise both aesthetics and structural integrity of a building. WRBs act as the first line of defense, preventing water from entering the building walls and affecting structural components. Whether it’s rain, snow, or humidity, a properly installed barrier keeps moisture out, preserving the stucco/plaster and preventing damage to the structure and interior finishes.

2. Energy Efficiency: Effective weatherproofing contributes to energy savings. WRBs can minimize air leakage and enhance energy efficiency. Consider this: a well-insulated building retains heat during winter and stays cool in summer. Your work thrives when the temperature fluctuations are minimized.

3. Durability and Longevity: Plastering contractors invest time and skill in creating beautiful surfaces. However, without adequate weather protection, all that effort could be in vain. A durable barrier ensures that the cladding stands the test of time, maintaining its elegance and functionality.

4. Air Barrier Functionality: Air infiltration compromises energy efficiency and indoor comfort. WRBs double up as air barriers, sealing gaps and cracks. When you apply plaster, the barrier beneath ensures that conditioned air stays indoors, reducing the load on HVAC systems. Your clients benefit from lower utility bills and a comfortable living environment.

5. Compatibility with Cladding Systems: Exterior cladding materials—whether stucco, siding, or masonry—rely on WRBs and flashing for building performance. As a plastering contractor, understanding the interplay between these components is crucial. WRBs and flashing facilitate proper drainage, preventing moisture accumulation behind cladding and mitigate potential damage to the structure and your work.

6. Collaboration with Other Trades: While you may not directly install WRBs, collaborating with other trades is essential. Coordinating your work with general contractors/builders, framers, waterproofing and roofing contractors ensures seamless integration. Successful long-term building performance is most probable when the entire team works together and recognizes the significance of properly assembled wall components and their role in weatherproofing.

The Art of Flashing

Flashing complements WRBs by redirecting water away from vulnerable areas. Our building codes and related ASTM documents discuss flashing and indicate to some extent where and how it should be installed as well as what kinds of flashing materials are appropriate for use with your work. Properly installed flashing at intersections with dissimilar materials, around windows, doors, and penetrations prevents water intrusion. As a plastering contractor, it is important that you inspect the flashing prior to starting your work. Well-executed flashing ensures that your work remains free from unsightly stains and deterioration.


In the symphony of construction, weatherproofing and flashing play harmonious yet indispensable tunes. As a plastering contractor, embrace the role of WRBs and flashing—they’re your silent partners in creating resilient, beautiful structures. Remember: a well-protected building not only withstands the elements but also showcases your craftsmanship.

So, next time you’re installing your work, protect and appreciate the water-resistive barrier beneath—the unsung hero that ensures your artistry endures.