A Buyer's Guide to Structural Insulated Sheathing

This home is under construction, and showcases ThermalStar SWI underneath the siding.

A successful build starts with a solid base, and finding efficient and effective products is the key to a strong foundation.

Choosing the right structural sheathing is an important factor in any building. But not all products are built the same, and it can be difficult to sort through the differences to find the right product for your project.

Let’s talk about everything there is to know about structural insulated sheathing, and how Atlas 4-in1 SWI products offer a multitude of benefits you may be missing if you only look at traditional sheathing options like OSB.

Top Importance: Code-Compliant Products

The most important factor in choosing structural sheathing is to make sure it is appropriate for your project and meets all the codes for your location. Otherwise, the sheathing does not fulfill its purpose, meaning more money is being spent to fill the gaps later on.

Structural sheathing should have evaluation reports readily available when you are considering your options. OSB and plywood will have these. Fiber sheathing, like Atlas fiberboards, also has individual evaluation reports so you can get a better idea of how it works.

The evaluation reports should provide information on the overall structural performance. For insulated sheathing, additional testing should be performed. For example, Atlas uses DJR Engineering to test their insulated sheathing products for R-value performance to show the buyer exactly how the product will perform. It is important to ensure the R-value is tested and not just claimed.

Water and Air Barrier

A labeled image of wall sheathing, showing the water-resistant barrier and air barrier, graphite enhanced polystyrene continuous insulation and fiberboard structural sheathing.


One primary of choosing insulated sheathing over traditional structural sheathing options is the fact that all the additional components are integrated into a single product. Straight OSB provides the structural element, but insulation and weather barriers must be added separately.

Insulated alternatives, like Atlas ThermalStar SWI, come with integrated film facers that create a water-resistive and air barrier when properly flashed and taped. This makes creating an airtight and energy-efficient home much faster and easier to achieve.

Most evaluation reports test for elements like air barrier abilities, waterproofing and weather resistance.

Included Installation Instructions

If you’re working with structural products, you’re dealing with the structural foundation of your house or building. It is imperative to make sure the products are installed correctly because, if not, the structural sheathing could dramatically affect the structure.

Wind load resistance is particularly important when it comes to structural sheathing, and if improperly installed, strong winds could displace the walls.

Structural sheathing should have detailed installation instructions along with the evaluation reports.

Easy Installation

Especially considering the current labor shortage, it is important that the sheathing product doesn’t require numerous workers or hours to install.

Some sheathing options, like OSB, are heavy and require a team and sometimes extra equipment to install. There are several lighter options available like Atlas ThermalStar SWI — even with dryline, foam, film and glue, it’s still up to 75% lighter than OSB.

These lighter structural sheathing options are much easier to handle and can be installed by a single person rather than a whole team. The ease of use and handling also speeds up the installation time and can lead to significant financial savings on labor.

Another factor to consider is how often the structure will need inspection during installation. For example, OSB must be inspected once installed, then inspected again after the building wrap is complete, sometimes even more. It can take days each time an inspector is called to the site, slowing down progress.

All-inclusive products can be inspected once because all the parts are integrated into a single unit. This saves on installation steps and inspection delays.

Dimensional Stability

A job site with wall sheathing going up on a structure. There is a blue sky in the image.

A lot of structural products, like OSB and fiberboards, are especially susceptible to expansion and contraction which can work nails out. Edges can also get wet, creating a failure point in the structure.

Moisture resistance is particularly important. Some products absorb moisture and begin rotting at the base leading to structural loss. The installer also needs to make sure the fasteners are correctly installed to not create a failure point.

Structural sheathing made with water-resistant materials and weather barriers can help prevent moisture from seeping in and ruining the integrity of the structure.

R-Value Component

Not all sheathing products are manufactured with insulation and R-Value in mind. These options need extra products to provide code-compliant R-value levels, air and weather barriers and continuous insulation.

But structural insulated sheathing is designed to provide the necessary insulation for the building. Look for products that are compliant with building codes and provide long-lasting R-value to help your structure run more efficiently.

Some products, like Atlas ThermalStar SWi, both supply sufficient R-value, and its laminated sheathing provides other benefits like water resistance, an airtight structure and continuous insulation for maximized safety and productivity.

Sheathing Make-Up

You should take into consideration what the sheathing is made of. Engineered wood products like composite wood and plywood contain formaldehyde — a known carcinogen — due to the products used to bind the wood together.

Choose a brand that does not use formaldehyde in any of their resins when manufacturing structural sheathing products.

Is Custom Sizing Available?

Most sheathing comes in standard sizes, and options like OSB include a premium for custom sizing, hurting installation time and requiring more labor to cut the product down on-site.

Look for a company that offers custom sizing without any additional charge. Customizing during the manufacturing process allows for the perfect fit on-site. It also reduces waste by eliminating cut-off pieces and recycling any excess back into the production process.

Benefits of Atlas ThermalStar

Our versatile ThermalStar Wall products provide high-performing continuous rigid insulation to meet all of your wall sheathing needs. Coming with a limited lifetime warranty for physical and thermal performance, our ThermalStar products have multiple thicknesses and compressive strengths to ensure your building’s integrity for years to come.

ThermalStar offers consistent, long term R-value to protect your structure now and in the future, along with minimal long-term moisture retention that can dry quickly to keep you and your structure safe. In addition, our product’s high vapor permeability adds to your building's moisture durability.

We believe in providing your structure with the best products possible while also being kind to the planet. Our ThermalStar line is environmentally friendly, as it has a low global warming potential and zero ozone depletion potential.

Choose Atlas for Your Structural Insulated Sheathing Needs

When it comes to finding the right products for your home or building, rely on Atlas for all of your structural insulated sheathing needs. Our 4-in-1 products will save you time, labor and money, even during the current labor and materials shortages.

Atlas experts are ready to answer any questions you may have and help you determine the perfect product for your next project.

Find a rep today to get started with Atlas today!