07/29/2026
Material costs on high-performance roof assemblies add up fast, and the default is to spec everything new. On a large roof, that decision alone can move the budget significantly without changing how the assembly performs.
This roof assembly consists of 4 inches of rigid insulation: a base layer of 2 inch reclaimed polyiso topped with 2 inches of XPS. The reclaimed polyiso runs $24 a sheet against $65 for new XPS, and across an entire roof that difference is substantial. The layered assembly still lands at roughly the same R-value as 4 inches of new XPS, so the client keeps the performance and loses the premium.
When the impact on performance is negligible, finding and leveraging cost savings is our responsibility as the builder.