Beyond adding aesthetic value to a structure, exterior finishes in construction effectively protect any building from inevitable wear and tear. Without expert exterior finishing, the integrity of a structure will not stand the test of time. Although conventional exterior finishing methodologies and materials have functioned well enough throughout the years, new challenges within the construction industry demand greater innovation.

The infrastructure labor shortage is one such challenge. With approximately 40% of the current U.S. construction workforce retiring over the next decade, it’s vital that industry leaders evaluate their processes in order to increase efficiency and reduce strain on their most skilled laborers. This is especially apparent regarding exterior finishing, where much of the work is highly specialized and requires extensive training to master.

A great variety of new products have been developed to resolve many installation and performance issues that impact exterior finishes—without demanding extra attention from overwhelmed expert laborers. Many of these new products have been engineered to directly combat the issues installers face when using the traditional materials. These products take pressure off of skilled veteran installers and make the process of training novice laborers much more effective and efficient—enabling them to reach a higher level of installation ability faster.

Additionally, product innovation supplements the skill level of novice laborers. Products like Structa Wire and E-Flange™ take technique out of the equation, by factoring the results of that technique (such as greater embedment) into their features. Therefore, every installer has the ability to achieve the same high-end result—regardless of skill level.

In the end, specifying these improved materials and solutions enables you to ensure that exterior finishing projects are correctly installed from the beginning, which keeps operations on track and reduces the risk of callbacks and structural failures.

To offer greater insight, ClarkDietrich created the following article to:

• Discuss the various types of exterior wall finishing materials
• Elaborate on the difficulties associated with exterior finishing
• Highlight opportunities to increase overall efficiency, and optimize results through product innovation and constant improvement to the products and processes that accompany them, to provide higher quality finishes faster and more repeatedly

Essential Exterior Building Materials for Finishing

It’s clear that the quality of exterior finishing materials, and of the overall installation process, directly influence the life span of a building. Admittedly, the materials selection process can often feel overwhelming—with so many components to consider, it’s easy to get lost in the details. Recognizing that the sheer volume of information surrounding exterior finishing components can often feel unmanageable, we compiled the list below to easily connect you to the answers and resources you need to get things done right.

Metal Lath

Metal lath’s lightweight nature offers a simple attachable foundation for plaster application. The lath openings are designed to help plaster key around the metal, achieving a secure bond and seamless surface plane. Using expanded steel, metal laths are positioned flat across the stud plane and are attached with wafer head lath screws, staples, or nails. All quality metal lath products should meet the requirements of ASTM C847.

Metal lath comes in two configurations:

• Self-furring for solid substrates per ASTM C1063
• Paper-backed for plaster or stucco applications

Although there are many lath variations available, the metal lath creates a composite cladding, which enables the cladding system to better withstand wind loads and static forces that create stress cracks within plaster embedment. To learn more about lath embedment best practices, see our white paper.

Corner Beads

Corner beads are placed on each exterior stucco corner, providing reinforcement and strength at critical junctures. This finishing product is usually stapled, clinched, or nailed into place. Galvanized expanded metal is the most common material used to create corner beads, but they also come in:

• Vinyl / PVC
• Welded Wire
• Zinc Alloy

When installed correctly, corner beads provide reinforcement to damage-prone corners and a finished look to the plaster application. As an essential component of any build, corner beads come in a wide variety of styles, each designed to meet different application requirements.

Casing Beads

Casing beads—also called plaster or stucco stops—function to terminate stucco and plaster at their junction with dissimilar materials. This is done along windows, doors, and other fenestrations included throughout a structure. Similar to corner beads, there are a wide variety of casing beads available, making it easy to source beads for any type of wall design. Although, out of all the models, the short flange casing bead is the most common. However, premium products like the E-Flange™ Casing Bead with BackerBead® have been designed to reduce labor times and improve product performance for moisture penetration and stucco embedment.

Starter Strips for Exterior Walls

Not to be confused with roofing starter strips, starter strips for exterior walls are placed at the bottom of each partition in order to secure the first pieces of siding. All starter strips function as perimeter base support for Exterior Insulation and Finish Systems (EIFS). Additionally, more advanced starter strip models are designed to let moisture escape through built-in weep holes and tracks, protecting walls from vapor and liquid water by allowing the wall to drain and dry. Other starter strips require laborers to drill the holes and add tracks themselves—resulting in dramatically increased labor times and reduced consistency in the spacing and functionality of the weeps. These features are especially critical for stucco walls, which easily succumb to moisture problems.

Weep and Sill Screeds

Weep and sill screeds are pieces of metal or vinyl flashing that connect to the bottom of exterior walls. Their main function is to provide a drainage plane which directs moisture away from the wall system. These weep holes can be placed in a variety of locations but are usually found at the back side of the trim at the base of the wall. Weep screeds are important for any structure but are especially critical for stucco exteriors. In fact, Chapter 7 of the International Residential Code (IRC) requires weep screeds to be installed at the bottom of stucco walls.

As is the case with most exterior finishing materials, many variations of weep screeds exist to serve different functions. For example, foundation weep screeds protect walls from wetness on frame construction at the foundation line. In a different vein, mid-wall weep screeds are placed in the middle of a partition to accommodate thermal expansion and contraction of separate substrates within the wall's fabrication.

Alongside weep and sill screeds, drip flashing should be added to door openings, window openings, and foundation lines for additional moisture protection.

Control Joints

Control joints function to alleviate stress from the wall and reduce the risk of expansive cracking in walls and ceilings. To achieve this effect, control joints are placed where stress concentrations are most likely to occur and allow for additional longitudinal movement. Although some disparage the use of control joints because of their somewhat choppy appearance, control joints are absolutely essential to prevent damage caused by the natural thermal expansion and contraction of a structure.

Additionally, control joint intersections ensure seamless connections and strong bonds between all components. To provide a proper fit at all connections, all ClarkDietrich intersections are custom-fabricated to meet unique project requirements.

Expansion Joints

Expansion joints are made to control structural movement and reduce the risk of damage to both internal and external finishes. The structure of expansion joints anticipates shrinkage in a building and allows room for additional movement. Expansion joints may be placed on the butt ends of adjacent panels, and on the inside or outside corners of a structure. When installing expansion joints, careful movement calculations are required so stability and weathertightness of the structure remains intact.

Reveals

Reveals are designed to fabricate an architectural break in a wall, to provide a stronger bond between each juncture to reduce the risk of separation. Their perforated flanges allow base coat mixtures to seamlessly flow through and bond the substrate. To reduce moisture damage, some reveals are produced with a combined drip screed to assist with moving water away from the wall system. Although reveals do offer structural support, it is important to note that they should never be used instead of control or expansion joints.

Rainscreens

Rainscreens can be used to improve drainage, ventilation, and thermal control of a wall system. A rainscreen’s drainage plane is engineered to draw moisture out of the system to prevent continuous and unmitigated moisture penetration. If a rainscreen is not used, moisture is able to seep into the external surface of a wall and become lodged within the cladding system. This will invariably cause mold and rust to spread, which can severely compromise the system.

Although this list covers the basics of exterior finishing materials, it’s not completely comprehensive. For additional information regarding miscellaneous materials, installation instructions, CAD details, regulations, and more, see our exterior finishing page.

What Are the Types of Exterior Walls?

Some of the most popular types of exterior wall materials used in modern construction include:

1. Stone Veneer
2. Vinyl/PVC
3. Fiber Cement
4. Composite
5. Brick
6. Wood
7. Stucco

In this section, we will review the pros and cons of each material at length.

1.  Natural Exterior Stone Veneer Siding

Stone veneer is not usually applied to all areas of a building and is mainly used as a feature façade. Natural stone veneer siding is crafted from thinly sliced, quarried stone, and shaped to meet design specifications. Aside from its natural beauty, the main appeal of stone veneer is its durability. Stone veneer is considered to be the most durable siding option and will outlast any other material when properly installed.

Unfortunately, durability and style come at a high price, making natural stone veneer one of the most expensive exterior siding materials available. Aside from its cost, stone veneer’s weight often demands additional fixtures and structural substrates. As a result of this, labor and installation costs are often higher.

2.  Vinyl Siding

As one of the most affordable and versatile exterior siding options, vinyl is an ideal material for quick projects and smaller budgets. From an aesthetic perspective, vinyl siding comes in many varieties, making it excellent for all sorts of architectural designs. The more significant downside to vinyl siding is that large holes and cracks cannot be mended. Instead, the siding needs to be replaced entirely.

3.  Fiber Cement Siding

Much like stone veneer, fiber cement offers great durability and requires very little maintenance. Unlike stone veneer, the aesthetics of fiber cement are fairly versatile. It can be used to mimic stucco, stone, shingles, and many other finish styles. The price of fiber cement is considerably higher than all other siding options, aside from natural stone. Its weight also presents several structural challenges during construction, and often demands that expert laborers be employed.

4.  Composite Siding

Similar to vinyl siding, composite options—also called engineered wood siding—are fairly affordable. Made from wood fibers and resin, composite siding can be manufactured to mimic natural wood aesthetics. Composite siding is mostly durable and can withstand water, as well as various pests.

However, the resin coat of composite siding may crack over time, making it more vulnerable to water damage if maintenance is not completed in time. Additionally, variations of this siding option are fairly new to the market, leading many to believe that their true value is yet to be determined.

5.  Brick Siding

Aside from its obvious aesthetic appeal, brick siding is impressively weather-resistant, low-maintenance, energy-efficient, and environmentally friendly. However, brick siding costs significantly more than vinyl, composite, and even wood siding. Moisture also remains an issue and can easily damage the framing of a brick building.

6.  Wood Siding

In addition to being fairly long-lasting and strong, wood’s ability to be stained and painted offers seemingly endless aesthetic possibilities. Its biodegradable and renewable nature, similar to stone veneer and brick siding options, are also appealing.

On the other hand, wood siding is vulnerable to pests, prone to rot, and easily succumbs to fire. Continuous maintenance and re-staining are also required to maintain durability and quality.

7.  Stucco Wall Siding

Stucco is extremely durable and requires little maintenance. If proper installation and maintenance routines are followed, then stucco can last several decades. One of the common practices used in creating a stucco finish is to use epoxy, which prevents breakage and cracking.

Although more affordable than stone, brick, and wood, stucco installation costs can be fairly high. This is because stucco requires multiple coats and expert supervision throughout installation. Lastly, stucco moisture problems are very worrisome in non-arid climates. One such issue is dry rot behind stucco, which eventually causes the material to crumble away, compromising the entire structural stability of a building. However, labor-saving products like Structa Wire or E-Flange™ can be used to prevent  these issues in all types of exterior siding.

What Is the Best Material for Exterior Walls?

Selecting the best exterior wall material depends on a number of factors including:

• The installation process and labor costs
• Design and aesthetic preferences
• Environmental conditions
• Longevity and durability
• Code-compliance
• Sustainability
• Versatility
• Warranty

Regardless of the material used to construct your walls, damage will occur if proper precautions are not taken, and if products are not installed according to best practices.

Mitigating the Installation and Performance Issues of Exterior Finishes

As was mentioned in the previous section, cracking and moisture intrusion remain the most pressing issues for builders. One factor that contributes to increased cracking in cement plaster is minimal embedment of the lath in the scratch coat of plaster. This leads to a lack of connectivity which can cause these materials to move independently of each other as thermal expansion and contraction occur. The end result is stress cracks throughout the cladding.

In regard to moisture intrusion, heavy wind loads, and rain often force water to flow behind a building’s siding. The increased air pressure pushes water through joints, nail holes, and other openings. Even if wind speeds remain minimal, moisture will inevitably migrate through gaps and reach the back of panels via capillary action.

As has been the case for quite some time, moisture and water damage throughout building exteriors consistently lead to expensive and drawn-out lawsuits. In fact, water damage from leaks accounts for 70% of construction lawsuits. In most of these cases, water intrusion can be traced back to poorly designed or faultily installed weather barriers and joints. These installation issues ultimately result in moisture repeatedly infiltrating a building’s cavities.

Because of the opaque nature of exterior wall cladding materials, it’s easy to miss red flags that could lead to cracks and moisture intrusion. Additionally, things become even more complex when skilled labor is hard to come by and deadlines are fast approaching. So, what’s to be done?

Specifying new and improved products ensures that exterior finishing installations are set up for success from the very beginning of the process. Let’s review an example.

Eliminating the Risk of Stucco Failures and Remediation Costs

Although moisture and crack protection are important for all structures, it’s absolutely vital for stucco walls. ClarkDietrich’s Easy Embedment System™ (EES) was designed to address the two main contributors of stucco failure:

1. Lack of embedment
2. Failure to caulk the trims at the time of installation
3. Inconsistent furring depth across the base metal
4. Irregular fastener spacing
5. Improper incorporation of control joints
6. Absence of drainage and drying functions

ClarkDietrich’s EES provides a reliable foundation for lath embedment resulting in durable, long-lasting stucco cladding. Additionally, this system was engineered to simplify the stucco application process and provides inexperienced contractors with the tools they need to efficiently and accurately complete expert-level installations. In short, EES enables the greatest level of embedment possible, and eliminates the challenge of sourcing a crew of hard-to-find experts.

So, what does EES look like in action? ClarkDietrich recently had the privilege to assist with the 2022 Orlando Airport expansion. Our EES system was chosen for this important project because of its efficiency and ability to create finishes that will stand the test of time. To effectively meet the challenges of such an extensive project (164,000-square-feet of exterior stucco application), our EES system provided:

• Quality and Ease-of-Use | To offer greater efficiency, the Structa Wire component of the EES system is simply rolled over door and window openings, and the wires are easily cut away. Additionally, Structa Wire effectively enhances the performance and durability of stucco cladding while providing a safe method for installation.
• Laths that Run Vertically | Mega Lath, individually specified in a vertical application for this project, was crucial to the speed and success of the installation at the Orlando Airport. E-Flange™ Casing Beads were also incorporated to complete the system and enhance embedment.
• BackerBead® | In combination with E-Flange, BackerBead features a preset blue backer rod that is connected to a vinyl casing bead and set to height and depth specifications. This allowed the installers to caulk around openings with precision and provided a consistent depth on the wall, eliminating the need to align and attach the rod in the field, providing a repeatable caulk tray for each opening on the project. Ultimately, the inclusion of BackerBead and E-Flange saved time and resources.

Aside from the EES system itself, ClarkDietrich provided on-site technical support throughout the duration of this project to help ensure proper installation and answer additional questions.

Because of the efficiency, durability, and reliability of the EES system, the Orlando Airport project was completed quickly and without error—resulting in a lasting finish that will maintain structural integrity for years to come.

In conclusion, exploring new products and processes helps construction leaders navigate the shortage of skilled labor, while reducing callbacks and failures. Feel free to explore our white papers and other resources if you’re interested in learning more about creating efficiencies throughout exterior finishing processes.