Is Polyiso the Best Insulation for Roofs and Walls?
Compare polyiso, fiberglass, mineral wool and spray foam - R-values, cost, fire and cold-climate performance to help choose the best roof and wall insulation.
Is Polyiso the Best Insulation for Roofs and Walls? Polyiso insulation is a top choice for many roofing and wall projects due to its high thermal resistance (R-value of 5.6–6.5 per inch) and versatility. It’s lightweight, easy to install, and often doubles as an air and moisture barrier when properly sealed. However, its performance can decline in extremely cold climates, and it requires a fire-rated covering for interior use. Here's a quick breakdown: - Pros: High R-value, thin layers meet code requirements, energy-efficient, recyclable, and eco-conscious manufacturing. - Cons: R-value decreases in cold weather, not suitable for below-grade use, and requires additional fire protection indoors. Compared to alternatives like fiberglass, mineral wool, and spray foam, polyiso excels in thermal efficiency and space-saving applications. However, each material has strengths depending on your climate, budget, and project needs. Quick Comparison | Material | R-Value per Inch | Cost | Key Stren...