What is Polyiso Wall Insulation?
Polyiso wall insulation is a building material commonly used in both residential and commercial structures. Whether you’re looking for wall insulation for your home remodel or your new construction project, polyiso wall insulation will provide a tailored solution for your next project.
Of all the building materials available for insulating the building envelope, rigid foam board—in the form of polyiso—is a superior option.
Benefits
Just claiming that something is superior doesn’t make it so. Let’s back up our statement with the facts. Here are just a few of the benefits of using polyiso wall insulation on your next project:
Easy to Install
The nature of polyiso is that it’s a rigid foam insulation board. That means it’s lightweight, it can be cut by hand into custom shapes and sizes, and it holds its own when attached to your studs.
Polyiso boards come from the factory in modular sizes, typically 48” x 96” (4’ x 8’) or 48” x 48” (4’ x 4’). The thickness can be customized from ½” up to 4-1/2” thick per layer.
Polyiso wall insulation can also be installed in multiple layers, if desired. Materials that are easier to install mean decreased labor costs for your project.
Continuous Insulation
As building codes evolve, “continuous insulation” is a term that appears more and more.
Continuous insulation calls for a constant thermal resistance (R-value) across the entire surface area. Today, many building codes require continuous insulation throughout the building envelope. Polyiso wall insulation is an ideal material to use for continuous insulation because it naturally provides a continuous R-value. That’s because polyiso wall insulation boards are butted up against each other to create a continuous, smooth surface on the wall.
Performance
The purpose of building insulation is to provide thermal resistance—so that heat loss is minimized and energy is conserved. Insulation performance is measured in R-value.
The higher the R-value, the better insulated your building is. Polyiso wall insulation carries an R-value of R6 per inch, which outperforms other insulating materials like fiberglass batts when comparing similar material thicknesses. A higher R-value per inch means you’ll be able to get more insulating power out of a thinner material that fits inside your wall cavity.
Versatility
Polyiso wall insulation can be customized to fit your project’s needs and budget. Not only does it come in a wide range of thicknesses and sizes, but it also comes with different types of laminated facers to achieve additional material properties. For a more economical option in concealed applications, you can choose a standard facer, and for projects where you want to turn your insulation into a structural nailboard, you can fasten your exterior finishes to a plywood laminated polyiso product such as ECOMAXci® FR Ply.
FAQs
Where is Polyiso Wall Insulation Used?
Polyiso wall insulation is used on the vertical surfaces of the building envelope—on the walls that separate the inside of your building from the outside. You’ll find polyiso wall insulation used on exterior foundation walls, on the interior side of basement walls, on the exterior side of stud walls, and even inside masonry wall cavities.
What is the R-Value of Polyiso Wall Insulation?
The R-value of polyiso wall insulation varies by manufacturer, but is typically around R5-R6 per inch. Rmax polyiso wall insulation products, including Durasheath® and Thermasheath®, carry an R-value of R6 per inch. That means one inch gives an R-value of 6. For your next project using one of these Rmax polyiso wall insulation products, you can achieve R20 with a single layer of 4” thick boards or two layers of 2” thick boards. Consult the specific product data sheets for exact R values.
Is Polyiso Wall Insulation Waterproof?
The foam core of polyiso wall insulation is naturally water-resistant because of its chemical makeup (thermoset plastic) and closed-cell structure. It’s actually the facer of polyiso that determines whether the boards are fully waterproof. A cellulose (paper) facer is not waterproof, while a foil facer (aluminum) provides enhanced water resistance.
How Do I Attach Polyiso Wall Insulation?
You have three choices of installation methods for polyiso wall insulation, depending on your installation. Most often, polyiso wall insulation is mechanically attached to studs, plywood, or furring with screws that have large, specialized washers to secure the insulation. Another installation method is adhering polyiso wall insulation to a substrate (such as a concrete wall) with specialized construction adhesive. Lastly, in some cases—you can simply install polyiso wall insulation without any fasteners by using a loose-laid application. This method is used alongside metal furring channels that hold the boards in place or when backfilling a foundation wall with soil.
What Are Other Types of Wall Insulation?
Other common wall insulation materials include fiberglass batts or rolls, spray-foam insulation, loose-fill cellulose insulation, and other types of polystyrene foam boards like extruded (EPS) and expanded (XPS).