ISO 8145:2026

Thermal insulation — Mineral wool board for overdeck insulation of roofs — Specification

This document specifies the properties and acceptable tolerances for bonded human-made mineral wool thermal insulating board for the overdeck insulation of roofs of buildings. The product is intended for roofs carrying foot traffic by maintenance personnel only. This document specifies the properties to be declared by the manufacturer at the time of delivery, as well as some test methods for the determination of these properties. This document provides limiting values for most of the properties. These limiting values are for specification purposes only. Design values can be derived from these by considering the environmental factors affecting the thermal performance of the product, the influence of the product properties on installation, and the effect of workmanship on the thermal performance. This document applies to board with or without a membrane for the insulation of the upper surface of roofs under roofing systems protected against water. The properties of a facing membrane are not described. When the board is supplied with a facing membrane, it is not intended to be waterproof. The board specified in this document is intended to be fixed to the roof surface.

Isolation thermique — Panneaux rigides en laine minérale pour l'isolation par l'extérieur des toitures-terrasses — Spécifications

General Information

• Status: Published
• Publication Date: 29-Jan-2026
• ICS: 91.100.60 - Thermal and sound insulating materials
• Technical Committee: ISO/TC 163/SC 3 - Thermal insulation products, components and systems
• Drafting Committee: ISO/TC 163/SC 3 - Thermal insulation products, components and systems
• Current Stage: 6060 - International Standard published
• Start Date: 30-Jan-2026
• Due Date: 10-Jan-2026
• Completion Date: 30-Jan-2026

Relations

• Revises: ISO 8145:1994 - Thermal insulation — Mineral wool board for overdeck insulation of roofs — Specification
• Effective Date: 24-Sep-2022

Overview

ISO 8145:2026, Thermal insulation - Mineral wool board for overdeck insulation of roofs - Specification, is an international standard developed by ISO. This standard defines the properties, tolerances, and declared values for bonded, human-made mineral wool thermal insulating boards specifically designed for the overdeck insulation of building roofs. The mineral wool board is intended for roofs accessible to maintenance personnel and is designed to enhance thermal performance, fire safety, and durability. The specification covers both products with or without a facing membrane but does not address waterproofing properties when a membrane is provided.

The standard details the requirements manufacturers must meet at the time of delivery, including declared thermal properties, mechanical strength, and product consistency, ensuring reliable performance in construction projects.

Key Topics

• Product Dimensions and Tolerances

  • Nominal length, width, and thickness must be declared.
  • Controlled tolerances according to international measurement standards.

• Thermal Performance

  • Declared thermal resistance (R-value) and thermal conductivity (λ-value) measured according to ISO methods.
  • Provides procedures for determining these values using statistical quality control.

• Mechanical and Physical Properties

  • Requirements for deformation resistance, interlaminar strength, and breaking load.
  • Control of general product attributes such as absence of coarse material, even fibre distribution, resistance to mould and odours, and non-corrosiveness.

• Fire Behaviour

  • Products must comply with local fire regulations for roof insulation, considering the presence or absence of a membrane facing.

• Sampling and Conformity

  • Outline of sampling and conformity control methodologies to ensure ongoing product quality.

• Marking and Documentation

  • Clear guidelines on what information must be marked on the product packaging, such as manufacturer, product codes, thermal properties, and reference to ISO 8145:2026.
  • Comprehensive requirements for reporting and traceability, including test reports.

Applications

• Flat and Low-Slope Roof Insulation

  • Designed for overdeck installation under roofing systems where waterproofing is provided by other layers.
  • Suitable for commercial, industrial, and residential buildings requiring maintenance access.

• Energy Efficiency in Construction

  • Helps specifiers and builders select insulation to improve building thermal performance and support compliance with energy codes and sustainability goals.

• Roofing Systems with or without Membrane Facing

  • Applicable for installations both with and without a facing membrane-ensuring versatility in roofing design while clarifying that the insulation board itself is not a water barrier.

• Quality Assurance and Specification

  • Allows architects, builders, and procurement specialists to specify mineral wool boards with confidence, knowing that products meeting ISO 8145:2026 achieve a high, consistent level of performance.

Related Standards

ISO 8145:2026 references and aligns with several related international standards, supporting a comprehensive approach to thermal insulation for buildings:

• ISO 7345 – Thermal performance of buildings and building components – Physical quantities and definitions
• ISO 8301 & ISO 8302 – Methods for determining steady-state thermal resistance and related properties
• ISO 9229 – Vocabulary for thermal insulation
• ISO 12491 – Statistical methods for quality control of building materials
• ISO 12576-1 – Conformity control systems for factory-made insulation products
• ISO 29465, ISO 29466, ISO 29467, ISO 29468 – Methods for determining length, width, thickness, squareness, and flatness in insulation products
• ISO 29764, ISO 29765 – Methods for determining deformation and interlaminar strength

Adhering to ISO 8145:2026 enhances the reliability, quality, and compliance of thermal insulation systems for roofing applications. This standard serves as a critical reference for product manufacturers, architects, building engineers, and regulators aiming to ensure optimal performance of roof insulation in a variety of climatic and structural conditions.

Standards Content (Sample)

International
Standard
ISO 8145
Second edition
Thermal insulation — Mineral wool
2026-01
board for overdeck insulation of
roofs — Specification
Isolation thermique — Panneaux rigides en laine minérale pour
l'isolation par l'extérieur des toitures-terrasses — Spécifications
Reference number
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Sampling and conformity control . 2
5 Required Properties . 2
5.1 Dimensions .2
5.2 Fire behaviour .3
5.3 Thermal transmission properties .3
5.4 Deformation resistance .3
5.5 Interlaminar strength .3
5.6 Breaking load .3
5.7 General properties .4
6 Marking . . 4
7 Test report . 4
Annex A (normative) Determination of breaking load . 6
Annex B (normative) Determination of the declared values of thermal resistance and thermal
conductivity . 8
Bibliography .11

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 163, Thermal performance and energy use in
the built environment, Subcommittee SC 3, Thermal insulation products, components and systems.
This second edition cancels and replaces the first edition (ISO 8145:1994), which has been technically
revised.
The main changes are as follows:
— included reference to dimensional testing;
— revised testing procedure for thermal conductivity and thermal resistance.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
International Standard ISO 8145:2026(en)
Thermal insulation — Mineral wool board for overdeck
insulation of roofs — Specification
1 Scope
This document specifies the properties and acceptable tolerances for bonded human-made mineral wool
thermal insulating board for the overdeck insulation of roofs of buildings. The product is intended for roofs
carrying foot traffic by maintenance personnel only.
This document specifies the properties to be declared by the manufacturer at the time of delivery, as well as
some test methods for the determination of these properties.
This document provides limiting values for most of the properties. These limiting values are for specification
purposes only. Design values can be derived from these by considering the environmental factors affecting
the thermal performance of the product, the influence of the product properties on installation, and the
effect of workmanship on the thermal performance.
This document applies to board with or without a membrane for the insulation of the upper surface of roofs
under roofing systems protected against water. The properties of a facing membrane are not described.
When the board is supplied with a facing membrane, it is not intended to be waterproof.
The board specified in this document is intended to be fixed to the roof surface.
2 Normative references
The following documents are referred to in the text in such a way that some or all their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 7345, Thermal performance of buildings and building components — Physical quantities and definitions
ISO 8301, Thermal insulation — Determination of steady-state thermal resistance and related properties —
Heat flow meter apparatus
ISO 8302, Thermal insulation — Determination of steady-state thermal resistance and related properties —
Guarded hot plate apparatus
ISO 9229, Thermal insulation — Vocabulary
ISO 12491, Statistical methods for quality control of building materials and components
ISO 12576-1, Thermal insulation — Insulating materials and products for buildings — Conformity control
systems — Part 1: Factory-made products
ISO 29465, Thermal insulating products for building applications — Determination of length and width
ISO 29466, Thermal insulating products for building applications — Determination of thickness
ISO 29467, Thermal insulating products for building applications — Determination of squareness
ISO 29468, Thermal insulating products for building applications — Determination of flatness
ISO 29764, Thermal insulating products for building applications — Determination of deformation under
specified compressive load and temperature conditions

ISO 29765, Thermal insulating products for building applications — Determination of tensile strength
perpendicular to faces
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 9229 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
mineral wool
fibrous thermal insulation material manufactured from molten rock, slag, or glass
3.2
board
rigid or semi-rigid thermal insulation product of rectangular shape and cross-section in which the thickness
is uniform and substantially smaller than the other dimensions
4 Sampling and conformity control
Conformity control shall be in accordance with ISO 12576-1. Manufacturer shall declare which option they
have chosen.
5 Required Properties
5.1 Dimensions
The manufacturer shall declare the nominal length, width, and thickness of the board.
These dimensions shall be measured in accordance with ISO 29465 (length & width), ISO 29466 (thickness),
ISO 29467 (squareness), and ISO 29468 (flatness) and shall be subject to the tolerances detailed in Table 1.
Table 1 — Dimensional tolerances
Permissible deviations of measured Test meth-
Dimension
values from nominal dimensions od
±5 mm or ±1 %, whichever is the greater
Length, l on average of measured values for each ISO 29465
single specimen
±5 mm on average of measured values for
Width, b ISO 29465
each single specimen.
±3 mm on average of measured values for
Thickness, d ISO 29466
all specimens tested.
For each 1 000 mm of the longest face
dimension, the maximum deviation shall
be not more than 3 mm.
Squareness ISO 29467
The edge plane of the thickness dimension
of the board shall be not more than 3 mm
...