Specifying the right Air and Water Resistive Barrier system for construction projects has never been more important.  

The past few years have been tough on the construction industry, with inflation, uncertainties, high material prices, and labor shortages all taking their toll.

2024 has also shown just how significant the topic of sustainability is. Architects, contractors, and building owners are increasingly under pressure to meet sustainability goals and rising environmental standards as the industry looks to deliver energy-efficient buildings with lower environmental impacts.

Using the right products is crucial for effectively futureproofing a building's lifespan and achieving certain sustainability accreditations. This is especially true for AWBs (Air and Water-Resistant Barriers).

In this blog, we’re taking a closer look at AWB systems, exploring the differences between the types available and the benefits they can bring from a practicality and sustainability perspective.
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What is a Weather Resistant Barrier?

A weather-resistant barrier, also known as an AWB (Air and Water-Resistive Barrier), is part of an exterior system that protects building materials from water ingress while enabling the building to ‘breathe’.

They form a membrane around the building envelope, ensuring that any water penetrating the exterior finish does not pass through. Water damage can lead to the growth of mildew, rot, and rust, which, over time, can seriously impact the performance and lifespan of a building.

Choosing the right AWB system is, therefore, an essential part of the construction process—it can be the difference between a successful building and one that deteriorates prematurely.

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Types of AWBs – An Overview

There are several types of AWBs on the market – and choosing the right one can be challenging!

They each have their own characteristics and application methods, so it’s useful to consider multiple factors, including the project's environment, the surface they are being applied to, and the ease of application, before making a final decision.

The three main types of AWB are:

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Sheet Type AWBs are designed to control air and water leaks. They are “peel and stick” membranes, making them self-adhesive and can be applied straight to the substrate to construct a physical barrier.

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As the name suggests, Fluid Applied AWBs are coatings painted, rolled, or sprayed onto the substrate to protect a building’s envelope and enhance its overall performance.

Fluid Applied Vapor Permeable Air Barrier

There’s also the additional option of a Fluid Applied Vapor Permeable Air Barrier, like Elemax™ Air & Water Resistive Barrier Coating, which prohibits the passage of liquid water while allowing moisture vapor to pass through.

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The Benefits of Fluid Applied AWBs

Silicone based Fluid Applied AWBs like Elemax 2600 AWB coating can be excellent candidates for projects with tight budgets or deadlines.

This is because they are both fast-drying and easy to apply using brushes, sprayers, and power rollers. This enables a seamless, aesthetic finish that ensures a reliable, tight seal around joints and penetrations.

They also have the bonus of being fully adhered directly to a substrate, which is great for contractors looking to reduce time, effort, and labor costs. Some formulas don’t even require a primer and just need one coat, reducing the need to invest in additional products at a time when materials are scarce and expensive.

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AWBs – A Sustainable Solution?

The right AWB system can also help construction projects to meet their sustainability objectives.

As they form a membrane around the building envelope, AWB systems can improve insulation and assist in controlling internal temperatures. In addition to enhancing a building's internal comfort, AWBs can reduce the energy used by air conditioning, effectively reducing energy bills and the carbon footprint of a building.

This is great when trying to achieve sustainability goals such as LEED and Net Zero Emissions, as it can decrease a construction's environmental impact on its immediate and surrounding environment.

For example, a product such as Elemax™ 2600 Air & Water-Resistive Barrier Coating controls airflow and moisture throughout the building envelope and can help reduce energy use by up to 35%. It’s also solvent-free and has a low VOC (volatile organic compounds) content.

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Using AWBs to Create Aesthetic Designs

Looking to create aesthetic building designs that still perform in the real world?

As we move into the new year, the demand for contemporary, modern designs is expected to remain popular - and open-joint cladding is an effective way to enhance a building's visual appearance.

While this design is aesthetically pleasing, open joint cladding systems expose the exterior wall to water, wind, and UV rays - which can make the building vulnerable to the growth of mold, mildew, and rot within the wall cavity. As well as reducing the lifespan of a building, it can also cause several problems for architects, contractors, building owners, and tenants.

Elemax AWB coating, however, can provide a solution to this by acting as a protective shield for buildings. In addition to keeping materials dry, it can also increase the overall durability of a construction and minimize maintenance costs.

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Why Choose Silicone?

Using a silicone AWB can be particularly effective for extending the lifespan and performance of a building.

This is due to silicone's robust and durable qualities. These characteristics were demonstrated in a 30-year test we ran in 1983 to evaluate the long-term durability of a variety of sealant types and ascertain which performs best.  

After 30 years, silicone ranked higher than alternative chemistries for most of the criteria it was evaluated on, showing that they were frequently stronger, more flexible, and more resistant to extreme weather. This makes silicone AWBs a great choice for projects requiring long-term protection or buildings set against challenging environments.

Given the current sustainability trends and expectations, silicone products can be very valuable. They perform over long periods of time, helping to extend a building's lifespan and reduce the need for total renovation work.

Read more here.

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Alkoxy vs Oxime – Silicone AWB Coatings

‍ When choosing silicone sealants and coatings, the chemistry really matters!

There are two main types of silicone formulations used in silicone AWB coatings: Alkoxy-based silicone and Oxime-based silicone.
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The names refer to the curing technologies used, and there are some significant differences between them. At Momentive, we use Alkoxy silicone because we believe it offers clear performance, safety, application, and lifespan benefits. We have deliberately excluded Oxime-based chemistry from our AWB coatings portfolio because of our commitment to environmental responsibility and its poor performance attributes.

In terms of performance, Momentive’s Alkoxy chemistry enables Elemax AWB coatings to offer primerless adhesion to a variety of materials, unlike Oxime-based solutions that require primers. Primerless adhesion not only helps save time and resources but also reduces the chance of product failure due to compatibility issues.

Alkoxy chemistry also offers key performance benefits for AWB systems, including significantly better elasticity than Oxime-based silicones. This flexibility helps Momentive silicone coatings and sealants resist building movement, keeping them watertight over the long term. Oxime silicones simply don’t “stretch” as well, increasing the risks of gaps that cause leaks.

There are also some serious safety concerns around Oxime-based silicones. This is because they release a substance called MEK / MEKO (Methyl Ethyl Ketoxime) as they cure, which is a suspected carcinogen known to carry health risks. MEKO is acknowledged as a chemical of concern in certain regions around the world, with restrictions, regulations and guidelines regarding its use already in place in Europe and Canada. Other regions look likely to follow. Alkoxy silicones release methanol, which does not have the same issues.

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Elemax AWB coating – An Effective Solution

High-quality buildings require high-quality solutions – and silicone-based AWB coatings are great candidates for ambitious, aesthetic projects that need to perform in demanding or difficult environments.

Make 2025 your best year of building with Elemax Air and Water Resistive Barrier coatings. 100% alkoxy silicone-based and solvent-free, this fluid-applied, vapor-permeable AWB coating creates a seamless membrane that helps protect against water ingress and control the flow of air through a building.

It allows a building to breathe while protecting it from the elements – stopping water droplets from getting in while allowing water vapor to escape.

Whatever the weather, whatever the project, Elemax AWB coatings will help weatherproof buildings and improve their lifespan. To find out more, please click here.