Building Insulation Products Plain EPS Insulation

Flute Fill

Cellofoam EPS Flute Fill serves as a void fill installed within the flute of an existing metal roof as a component of a retrofit system. The product is either loosely laid or mechanically attached to provide a uniform and level substrate. Cellofoam Flute Fill is custom cut with either a square or tapered edge to accurately fit nearly any metal deck or steel roof profile. The core of Flute Fill is a premium, rigid, modified expanded polystyrene (EPS) insulation with closed cells molded in a range of densities to provide a variety of compressive strengths to meet project specifications and requirements. EPS provides a long-term, stable R-value, superior compressive strength, moisture resistance, and energy and cost efficiency. It is 100% recyclable, and is often used as a replacement for Polyiso with up to 40% cost savings. Cellofoam EPS Flute Fill is a premium product, and is produced to meet or exceed ASTM C578, Standard Specification for Rigid, Cellular Polystyrene Thermal Insulation.

Cellofoam Flute Fill on a metal re-roofing application
FR Composite Sheet being installed over Flute Fill
FR Composite installed over Flute Fill in a metal re-roofing application
Flute Fill in a metal re-roofing application


Material Savings

EPS insulation provides the highest R-value per dollar compared to XPS and Polyiso. Cellofoam EPS Flute Fill may provide up to 40% cost savings over Polyiso flute fill.

Code Approvals

Cellofoam EPS is Underwriters Laboratory Listed, UL Classified TGFU.R7260, UL ER7260, for low slope mechanically attached or ballasted roof systems. Part of a Class A assembly over noncombustible decks. Please consult local building codes and membrane manufacturers for system requirements.

Stable R-value

The R-value of EPS is permanent because the only gas in EPS is air. Unlike Polyiso or XPS whose blowing agents outgas and therefore lose R-value, EPS R-values do not degrade over decades of use. Care should be taken in calculating flute roof system R-values where the insulation coverage may not be continuous, using standard industry methodologies such as those described in the ASHRAE Fundamentals Handbook.

Moisture Resistant

Cellofoam EPS is quick drying and does not readily absorb moisture from the air. Its closed-cell structure reduces the absorption and migration of moisture.

Premium Quality

Meets or exceeds ASTM C578 specs, with excellent dimensional stability, water absorption, and compressive strength characteristics.

Environmentally Friendly

Cellofoam EPS contains no formaldehyde or ozone-depleting CFCs or HCFCs. It is 100% recyclable and may contain recycled material.

Manufactured to your Needs

Cellofoam EPS Flute Fill is CNC hot wire cut to fit your flute profile. It is available in either square or tapered edges, lengths of 8, 10, and 12 feet, ASTM C578 nominal densities of 1.0, 1.25, 1.5, and 2.0 lb/ft3, and compressive strengths from 10 to 25 psi.


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We’re dedicated to manufacturing products that meet the highest standards of quality and performance. Need to know if Cellofoam’s products are right for your next project? Reach out to our team.