Interiors: Drywall Installation

Interior Installation Links:

Drywall and Other Finishes

Drywall is installed over InSoFast panels in the same exact way it is installed over traditional framing. Simply attach drywall to the InSoFast studs using all-purpose coarse drywall screws. Type W Bugle Head Screws attach single layer gypsum panels to InSoFast framing. Screws provide greater holding power than wallboard nails, minimize popping and help prevent damage to the panels. You should nail base and trim boards into the studs using trim nailer or hand nails.

Things to keep in mind:

    1. Allow 24-hours for the PL Premium 3X Stronger Construction Adhesive to fully cure before attaching any finishes.
    2. When installing InSoFast in a corner, be sure to solidly back the panel’s edges that don’t end in studs. See (Corners, Intersecting Walls) for more details.

Other links to get you started:

Drywall Fire Code and Alternatives

Important: InSoFast panels are manufactured using a flame retardant foam and are classified as rigid foam plastic insulation. They fall into the same class as pink, blue and yellow insulation boards which are required by code to be covered by ½” drywall or any other approved 15-minute thermal barrier (IBC 2603.4). If choosing an alternative to drywall it is important to check with your local building code official to make sure it meets your local requirements.

Securing Drywall near Inside Corners

    1. Cut the InSoFast UX panels about ¼" less than actual measurement needed so panels are not tight to the corner. Leaving this gap reduces push-out stress on the panels.
    2. Ensure that the corner is solid-backed by running a bead of adhesive along the panel (foam or stud) within 2" of its edge.
    3. Just before attaching drywall, place a bead of adhesive on the foam near the corner. The drywall is bonded to the foam and the foam has been bonded to the concrete, eliminating the need to a stud in the corner. PL Premium 3X is recommended because it is non-volatile and will not melt through the foam. For information, see Installation > Adhesives.
    4. Alternatively: you can attach drywall by screwing into a metal corner angle (2" x 2", 25ga sheet metal). Adhere the metal angle to the InSoFast panels by running a bead of adhesive approximately 1" from each side of the corner.

Securing Drywall near Outside Corners

    1. Use a metal corner angle (3" x 3", 25ga sheet metal) to wrap outside corners. Generally available in the roofing/flashing section of home improvement stores or drywall supply yards.
    2. Place beads of adhesive on the back side of the metal angle and press it against the corner. If necessary, hold the angle in place with duct tape.
    3. Hang drywall by screwing all-purpose drywall screws into the InSoFast studs and into the sheet metal corner angle. Install a second metal corner angle over the drywall using all-purpose drywall screws.


There are numerous types of finishes that are designed for or can applied to the InSoFast panels. The following is a short list of links to finish materials and application instructions.

Place a bead of adhesive approximately 1" from each side of the corner. Press 2" x 2" - 25 ga. sheet metal angle into adhesive. Attach drywall by screwing into the metal corner angle. Nail into intersecting stud. Attach drywall by screwing into the metal corner angle.

Stem or Partition Walls

Partition walls can be adhesively or mechanically (screwed) to the InSoFast panel's stud.

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InSoFast Plus Method

Need a higher R-value? No Problem! Start with a base of InSoFast continuous insulation panels they are feature-rich and easy to install. Then add rigid foam insulation over top of InSoFast panels.