Roof Insulation Boards

Variations and Benefits of Polyiso Insulation Boards

Roof insulation is a crucial component of a roofing system, contributing greatly to the building’s overall energy efficiency and fire performance. So much so, in fact, that above-deck insulation requirements are written into local building, energy and environmental protection codes.

roof insulation

What is ISO board?

Polyiso, or iso, is a high-performance insulation solution used in a multitude of applications, most notably, in this instance, residential and commercial roofing. Polyiso is short for polyisocyanurate, a rigid insulation board made of closed-cell foam. It is fabricated in 4’ x 4’ or 4’ x 8’ sheets to be used under roofing materials. Because of its cost-effectiveness and high R-value, polyiso is the roofing industry’s most widely-used insulating product for low-slope roofing.

r-value chart of insulation boards

ISO board variations

Polyiso can be manufactured in either flat or tapered panels. Flat panels are typically used to direct water to a gutter or drain on low-slope roofs, while tapered panels create a slant for drainage on flat roofs.

Polyiso cost

Like most building materials, the price point of polyiso boards can vary depending on the size and thickness of the sheets as well as the current market availability of the product. Typically, direct purchase of polyiso from a retailer such as Home Depot or Lowe’s will cost anywhere from $10 - $20 per 4’ x 8’ sheet.

Polyiso offers many benefits to residential and commercial roofing systems:

  • The highest R-value (5.6) per inch compared to other insulation products
  • Third-party certification for superior thermal performance
  • Widely compatible with most roof systems
  • Economical
  • Energy-efficient
  • Extremely lightweight (< 0.25psf per inch) with a significantly lower carbon footprint than other insulation materials
  • Superior performance in fire tests
  • Stability over a wide temperature range (-100°F to +250°F)
  • Low density, low water absorption and low vapor transmission
  • Not affected by oil-based waterproofing products, pesticides or fertilizers when properly installed
  • Cited by the US EPA for its low impact on the environment
  • Recyclable through reuse where permitted; contains recycled content

AKVM is dedicated to using only the most suitable products for your residential or commercial roof. To learn more or to schedule a free inspection, call 941-727-3996 or send us an email.

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