Commercial | Residential | Multifamily | Wall

Helping rooftops resist the elements

A durable Styrofoam™ Brand extruded polystyrene (XPS) foam insulation designed for low-slope commercial roofs. Cover all the bases with a product that eliminates the need for a thermal barrier as it resists moisture and freeze-thaw impacts. 


Styrofoam™ Brand Deckmate™ Plus

Extruded polystyrene foam insulation board with shiplap edges.


Features & benefits

Lightweight and durable
  • Easy to handle
  • Reduces waste
  • Resists damage
  • Closed-cell structure
  • Excellent freeze-thaw resistance
  • Excellent insulating characteristics
  • High moisture resistance
  • Direct-to-deck application
  • Easy, fast, flexible use on site
  • Eliminates need for thermal barrier to keep costs down
  • Boosts energy performance
  • Cost-effective

    Physical Properties

      Method Unit Value
    Thermal Resistance per inch (25 mm) @ 75°F (24°C) mean temp.<sup>1</sup> C518 ft2 •h•°F/Btu (m2 •°C/W), R-value (RSI)(1) 5.0, 0.87
    Compressive Strength<sup>2</sup> D1621 psi (kPa), min. 25, 20 (140)
    Flexural Strength<sup></sup> C203 psi (kPa), min. 50, 43.5 (300)
    Water Absorption<sup></sup> C272, D2842 % by volume, max. 0.3, 0.7
    Water Vapor Permeance<sup>3</sup> E96 perm @ 1” thick perm @ 2” thick 1.5 (90)
    Dimensional Stability, max<sup>5</sup> D2126, CAN/ULC S701 % linear change, max. 2
    Coefficient of Linear Thermal Expansion<sup></sup> - x105in/in °F (x102mm/m °C) 3.5 x 10-5 (6.3 x 10-2)
    Maximum Use Temperature<sup></sup> - Fdays
    Flame Spread<sup>4</sup> E84 Fdays 1.5
    Smoke Developed<sup>4</sup> E84 Fdays 165

    1 R means resistance to heat flow. The higher the R-value, the greater the insulating power.

    2Vertical compressive strength is measured at 10 percent deformation or at yield, whichever occurs first.

    3Based on 1” (25 mm) thickness.

    4These numerical flame spread and smoke developed ratings are not intended to reflect hazards presented by this or any other material under actual fire conditions.

    5Tested at 158°F/97% RH/7 days.


    Available Sizes

    R-Value Thickness (in.) Board Size (ft.) Edge Treatment
    5 1 4 x 8 Butt edge
    10 2 4 x 8 Butt edge
    15 3 4 x 8 Butt edge
    10 2 4 x 8 Butt edge