UK · Updated 2026 · How-to

How to Store PIR Insulation Outside: Trade Guide

PIR is bulky, expensive and easily ruined by rain. Whether you're a merchant storing overflow or a builder holding stock between projects, these six rules preserve thermal value and resale price.

The six rules

  • Pallet up, never on bare ground
  • Cover with proper insulation tarp (not builder's plastic — traps condensation)
  • Angle for water runoff
  • Ventilate the cover to prevent sweating
  • Rotate stock every 3 months to check corners
  • Never stack more than 8 sheets high without banding

Frequently asked questions

+How long can PIR live outside?

Correctly tarped and ventilated: 12+ months with zero degradation. Wrapped in tight builder's plastic: 3 months before condensation damage.

+Is UV a problem?

Yes — exposed foil oxidises within 6 months and thermal performance drops 2–4%. Keep it covered.

More SurplusBuilder guides