Sample Installation Image

The Foam Sheathing Committee (FSC) serves as a manufacturing-driven organization focused on developing solutions to building code issues and promoting the proper technical use of foam sheathing to the construction industry.

Find more resources about Foam Sheathing on the Continuous Insulation website.

Foam Sheathing Committee (FSC) Members:

Atlas RoofingDowGAFHunter PanelsJohns ManvilleKingspan Insulation LLCOwens CorningRMAX



Foam Plastic Insulating Sheathing (FPIS) Products are offered in three types:

  • Expanded Polystyrene (EPS) - ASTM C578
  • Extruded Polystyrene (XPS) - ASTM C578
  • Polyisocyanurate (Polyiso) - ASTM C1289

FPIS products come in many thicknesses to accommodate almost any end use.

Exterior wall coverings are attached directly through the FPIS into the framing or to furring attached through the FPIS to framing. Shall be installed in accordance with:

  • DRR No. 1303-04
  • Manufacturer’s installation instructions
  • The following general installation guidelines

Step 1

Verify FPIS and Framing

  • FPIS must have min. compressive strength of 15 psi
  • Must comply with ANSI/SBCA FS100 where wind pressure resistance is required

Note: Wind speeds shown in Table 1 are VASD. Where VULT is used, multiply wind speeds by a factor of 1.26

Wood framing may be any softwood species with specific gravity 0.42 or higher.

Steel framing must be:

Step 2

Verify Fasteners

Exterior coverings may be attached by the following methods:

(a) Cladding
(b) Fasteners
(c) Furring
(d) FPIS
(e) Framing
(f) Cavity Insulation
(g) Interior wall finish

  • Fasteners must meet penetration requirements per IRC Table R703.3(1) into:
    • Studs
    • Framing members
  • Where penetration into framing is not required, fasteners must extend ¼" beyond the opposite face of the sheathing per IRC Table R703.3.2

Step 3

Place Insulation Boards

Ensure wall is square and true and align boards with bottom edge of wall.

  • Verify stud spacing, blocking, and bracing requirements with manufacturer
  • Provide framing or blocking for attachment of siding and trim at transitions
  • Seams should not be visible from interior unless allowed by manufacturer

Step 4

Attach Insulation Boards

Space fasteners per manufacturer's instructions around edges of panel, through panels and into interior members

Drive nails flush and snug. Do not overdrive or underdrive nails.
Exception: Leave 1/32" gap (or as required by manufacturer) to allow for lengthwise thermal expansion of vinyl or aluminum siding)

Step 5

Trim Boards at Openings

  • Trim boards at all windows and door openings
  • Cover all framing with FPIS
  • Fit joints tightly

Step 6

WRB and Flashing

  • Ensure that a code compliant water-resistive barrier (WRB) and required flashing is provided
  • If using FPIS as a WRB
    • Seal all joints and openings and penetrations per manufacturer's installation instructions

  • At pipe and other small penetrations, seal gaps with silicone or expanding spray foam sealant
  • Seal joints and opening with joint tape per manufacturer's instructions

Repair damaged areas per manufacturer's instructions.