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Installation Guide

Looking for specific installation information? Try these links:
Installation Procedures for THERMAX™ Wall System (144KB PDF)
Product Storage – THERMAX™ (ci)
Product Storage – STYROFOAM™ Brand SPF
STYROFOAM™ Brand SPF (CM Series) Application Guidelines
Troubleshooting – STYROFOAM™ Brand SPF (CM Series)
SPF ICC-ES Report (116KB PDF)



Sequencing Overview
Installation Recommendations
Fastening Pattern for THERMAX™ (ci) Exterior Insulation

Sequencing Overview
Installation of the THERMAX™ Wall System can begin once the structural steel and exterior wall steel studs have been installed and braced.

By using the all-steel bracing design, a drywall or masonry contractor can begin immediately installing boards of THERMAX™ (ci) Exterior Insulation on the exterior of the building envelope. (Insulation can be left exposed for 180 days.)

As the contractor applies succeeding boards, WEATHERMATE™ Straight Flashing is adhered to adjoining board joints and at pre-determined thru-wall penetrations. Windows and other openings are flashed following the removal of excess THERMAX™ (ci) Exterior Insulation in these areas of the envelope.

With the building closed in, the structure has an insulated and weatherized envelope, which will allow for work to progress quickly on the interior of the structure. By completing this step, a building can begin to be conditioned, which can speed up the work of other trades beyond the exterior walls.

Once sections of insulation boards and flashing are in place, a contractor can follow this work and adhere a strip of flashing to the face of the insulation (where the tie will be inserted). Veneer ties used to anchor the final exterior of the building can then be mounted.

When the necessary ties are in place, masonry work or installation of other veneers can begin on these areas of the building. After the ties are secured to the steel studs on the interior, it is important to ensure that, if necessary, a floor line fire-stop is installed in the stud cavity.

Spray foam can now be applied in the stud cavity, covering the fire-stop (if installed) back to the floor edge to complete the air barrier, to further seal and insulate the envelope. Spray foam should be applied after the chosen veneer ties are in place. This allows free access for proper attachment of the tie. However, once the ties are in place, bricks can be laid on the exterior while a spray foam contractor foams a similar portion of the wall on the interior side.

This system of products provides scheduling overlaps that can save significant time on a project, minimizing negative impacts and providing an opportunity for multiple contractors to engage in finishing the exterior wall throughout the project.

Installation Recommendations

  1. With printed side facing to the exterior, install THERMAX™ (ci) Exterior Insulation horizontally with the shiplap edge up (for boards that contact the steel studs).
  2. Use maximum board lengths to minimize number of joints. Locate edge joints parallel to and on framing flange. Center end joints over supports and stagger in each course.
  3. Anchor to exterior face of exterior metal stud wall framing with appropriate fastener. Abut insulation boards tightly together around openings and penetrations.
  4. Fasten boards of THERMAX™ (ci) Exterior Insulation to each support with fasteners spaced 12" o.c. at perimeter and 16" o.c. in the field. See recommended fastening patternClick here for approved fasteners and veneer ties.
    Set back perimeter fasteners 3/8" from board edges and ends. One approved fastener/washer can be placed to bridge a maximum of two board edges. Drive fasteners to bear tight and flush with surface of insulated sheathing. Do not countersink.
  5. For optimum performance and to create a water-resistive barrier, seal all end and edge joints, and thru-wall penetrations, such as window and door openings, with WEATHERMATE™ Flashing.
  6. It is critical that flashing be attached in shingle fashion on the face of THERMAX™ (ci) Exterior Insulation and that all thru-wall penetrations are properly flashed to achieve a continuous drainage plane. A minimum overlap the width of the flashing is recommended. For example, if using 4" wide WEATHERMATE™ Flashing, overlap by at least 4".
  7. THERMAX™ (ci) Exterior Insulation boards should be properly repaired if damaged during installation. Repairs may include applying a strip of flashing over a small hole or filling a large hole with a piece of the insulation board and then sealing with flashing.
  8. Veneer ties can now be secured to the steel stud walls by applying a section of WEATHERMATE™ Flashing to the surface of the THERMAX™ (ci) Exterior Insulation prior to penetrating it.
  9. If necessary due to stud placement, the floor line fire-stop should already be installed. Finally, STYROFOAM™ Brand SPF (CM Series) can be applied to the interior of the stud cavity by a qualified SPF applicator.

Fastening Pattern for THERMAX™ (ci) Exterior Insulation

Fastening Pattern for THERMAX™ (ci) Exterior Insulation

Dow recommends a fastening pattern of 12" o.c. around the perimeter and 16" o.c. in the field. Perimeter fasteners can be detailed to bridge the gap of abutting board joints due to the 1.75" diameter of the washer used to fasten the board to the studs. This detail can be used to bridge a maximum of two board joints, thus two fasteners should be used at the intersection of three or four boards.

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