Top 4 Installation Techniques & Recommendations for Styrofoam™ XPS Insulation You Need to Know

Article | January 8, 2018
4 Installation Techniques for Styrofoam™ XPS Insulation

Top 4 installation techniques & recommendations for STYROFOAM™ XPS insulation you need to know

Have you ever seen a home or building built the same way twice? Given the specific needs of each project, installation and compatibility questions are among our top of our building science experts.

So we pressed our most experienced experts to the burning questions asked about installing STYROFOAM™ XPS Insulation, our award-winning building envelope solution.

1. What are the recommended adhesives for STYROFOAM™ XPS insulation?


This is the single-most popular question. Here’s the answer: Adhesives from Dow offer dependable, long-term service for a wide variety of applications and are compatible with most construction materials. Most commonly used adhesives with STYROFOAM™ XPS Insulation are ENERBOND™ Professional Foam Adhesive and GREAT STUFF PRO™ Wall Floor Adhesive

For a list of complete adhesives for all applications from Dow, browse through our adhesives solutions.

There may be other adhesive manufacturers compatible with XPS insulation. Check the adhesive container or with the manufacturer to determine if a particular adhesive is compatible with polystyrene-based insulations.

2. What are the recommended fasteners for STYROFOAM™?

There unfortunately isn’t one simple answer for this. The choice of fastener for STYROFOAM™ Extruded Polystyrene Foam Insulation is completely dependent on the application. There are many fastener manufacturers located throughout North America. You can consult your local construction supplier for advice on which fasteners should be used for a particular application.

A partial list of fastener manufacturers is shown here:

3. How is STYROFOAM™ used with sheathing seam sealing?


Caulking or taping the joint seam of an insulation sheathing board over metal or wood studs should be done to reduce air infiltration through these seams (the air that passes through the seam and into the building).

STYROFOAM™ Extruded Polystyrene Foam Insulation sheathings such as STYROFOAM™ CAVITYMATE™ or STYROFOAM™ Ultra SL Insulation provide a coat of continuous insulation over the stud members (when properly installed) and are treated with durable joint treatments such as GREAT STUFF PRO™ Gaps & Cracks or LIQUIDARMOR™ Flashing and Sealant as an integrated air and water barrier system.

For more information on controlling air infiltration, visit our website.

4. When z-furring is used to secure the insulation sheathing, is it still considered to be continuous?

The short answer: no. Insulation placed between z-furring does not meet the definition of continuous insulation. This is because the z-furring represents a line of continuous metal penetrating the insulation and short circuiting heat around the insulation. This dramatically reduces the effective R-Value of the insulation.

A continuous insulation layer can only be achieved when the amount of metal that penetrates the insulation can be made very small, such as when only fasteners penetrate the insulation.

When you compare the two illustrations, you can see that fasteners contain only a small fraction of the metal cross section as does the z-furring. Insulation held in place with fasteners is considered continuous, z-furring is not.

Download our typical detail set for further information.