Best Insulation for Shed: Materials and R-Values Choosing the best insulation for a shed determines how comfortable, dry, and energy-efficient the space will be. Whether converting a storage box into a weekend workshop, protecting garden tools, or finishing a small garden room, the right insulation and R-values cut heat loss, control condensation, and reduce running costs. This article explains R-values, compares common materials, gives climate-based R recommendations, and walks through a weekend DIY install plan so readers can pick the best approach for their shed. Use the Shed Insulation Calculator(/tools/shed-insulation-calculator) to turn shed dimensions, climate zone(/glossary/climate-zone), and intended use into wall, roof, and floor material quantities before pricing materials. TL;DR: - Choose insulation by use: unheated storage → R-7 to R-13 walls; heated workshop or living space → walls R-13–R-21 and roof R-30–R-49. - For high performance in limited cavity depth, use polyiso o...