{
  "brand": "ROCKWOOL",
  "checked_date": "2026-08-29",
  "version": "2026-08-29.1",
  "scope": "Steady-state plane layers, optionally one repeating timber layer. Excludes metal framing, ground-coupled floors, windows, junction psi values, moisture and fire design. No automatic fastener, air-gap or inverted-roof correction. Not a compliance certificate.",
  "reuse": "Original calculations and selection: CC BY 4.0, attribute Inzonex and link this page. Manufacturer property facts remain attributed to their sources; no rights are granted over manufacturer documents, images or trademarks. Not a manufacturer-endorsed calculator.",
  "products": [
    {
      "id": "flexi",
      "name": "ROCKWOOL Flexi",
      "material_class": "Stone wool slab",
      "application": "Roofs, timber and metal stud walls, and suspended floors",
      "source": "flexi",
      "range_source": "flexi-range",
      "thickness_mm": [
        50,
        60,
        70,
        90,
        100,
        120,
        140,
        180
      ],
      "lambda_w_mk": [
        0.038,
        0.038,
        0.038,
        0.038,
        0.038,
        0.038,
        0.035,
        0.035
      ],
      "declared_r": [
        1.3,
        1.55,
        1.8,
        2.35,
        2.6,
        3.15,
        4,
        5.1
      ],
      "note": "Listed UK variants only. Lambda changes from 0.038 to 0.035 at 140 mm; no interpolation across unlisted thicknesses."
    }
  ],
  "sources": {
    "flexi": {
      "title": "ROCKWOOL Flexi technical sheet, November 2025, page 3",
      "url": "https://www.rockwool.com/syssiteassets/rw-uk/downloads/datasheets/flexi.pdf"
    },
    "flexi-range": {
      "title": "ROCKWOOL Flexi UK listed product variants",
      "url": "https://www.rockwool.com/uk/products/flexi/"
    }
  }
}