Insulfoam Commercial Below Grade Insulation

With an extensive offering of below grade and under-slab insulating products, Insulfoam and R-Tech® brand expanded polystyrene (EPS) insulation products are engineered to stand the test of time.

Product Description

Insulfoam® Commercial Below‑Grade & Under‑Slab EPS Insulation provides factory-cut expanded polystyrene panels designed for foundation walls, slab-on-grade applications, plaza decks, radiant-heated floors, block-outs, landscape void fill, drainage board, cold storage, stadium seating, and more. Engineered for long-term installation, these panels not only insulate but also protect waterproofing and dampproofing systems during backfilling. Installed EPS maintains its published R-value over time and is backed by a 100% 20-year R-value warranty.

Key Benefits

  • Thermal Efficiency: Prevents up to 25% of heat loss in structures by insulating below-grade and under slabs.
  • Long-Term R-Value Stability: EPS remains stable over decades without thermal drift, unlike XPS.
  • Moisture Resistance: EPS dries quickly and absorbs less long-term moisture compared to XPS.
  • Protective Function: Shields waterproofing/dampproofing from damage during backfill activities.
  • Structural Strength: Offers compressive durability suitable for heavy-duty commercial applications.
  • Warranty-Backed: 20-year full R-value warranty supports long-term performance.

Best For

  • Foundation wall insulation
  • Under-slab insulation
  • Plaza decks & block-outs
  • Radiant-heated concrete floors
  • Drainage board & cold storage applications
  • Stadium seating insulation

Product Properties

Property Specification
Material Closed-cell EPS (Expanded Polystyrene)
R-Value Stability 100% R-value retention over 20 years (no thermal drift)
Moisture Behavior Low long-term absorption and quick drying—EPS retains less moisture than XPS.
Compressive Strength Multiple grades available; suitable for structural use under slabs
Panel Sizes Custom-cut: up to 40″ thickness; standard configurations include tongue‑and‑groove, drainage board, laminated, flute‑fill, and R‑Tech fanfold
Warranty 20-year 100% thermal performance coverage