A guide to firestopping materials

Verus Group • 27 February 2023

A guide to firestopping materials

Firestopping materials are essential components of fire protection systems in buildings. These materials are designed to prevent the spread of fire and smoke through the building's walls, floors, and ceilings. There are several different types of firestopping materials available, each with their own unique characteristics and applications. Here is a guide to some of the most commonly used firestopping materials:


  • Intumescent Sealants / Mastic

Intumescent sealants or mastics are typically used to seal gaps around pipes, cables, and other penetrations in fire-rated walls and floors. These sealants contain chemicals that expand when exposed to heat, creating a barrier that helps to prevent the spread of fire and smoke.

They come with different compositions for different uses, such as graphite or high expansion, or intumescent acrylic.


  • Firestop Mortar

Firestop mortar is a cement-based material that is used to fill large openings in fire-rated walls and floors. This material is typically used in areas where pipes, ducts, and other large penetrations need to be sealed.


  • Firestop Putty:

Firestop putty is a pliable material that can be moulded to fit around pipes, cables, and other small penetrations in fire-rated walls and floors. This material is typically used in areas where there is limited space to install other types of firestopping materials.


  • Firestop Pillows:

Firestop pillows are cushions that come in a variety of sizes, and are filled with fire-resistant materials. These pillows are typically friction-fitted around around pipes, cables, and other penetrations in fire-rated walls and floors where frequent access to the services they surround may be required, e.g. for maintenance purposes.


  • Firestop Collars:

Firestop collars are used to seal around plastic pipes and cables that penetrate through fire-rated walls and floors. They are mechanically fixed to the surrounding solid substrate, e.g. brick or block work. The 'padding' within the metal outer will expand when exposed to heat, creating a barrier that helps to prevent the spread of fire and smoke. It is extremely important that all fixings are used correctly to ensure performance in accordance with the manufacturer's test data.


  • Ablative Coated Batt or Boards:

Ablative coated batt is made from high density mineral wool or other fire-resistant materials with a high performance exterior coating. They come in large slabs, typically approximately 1200x600mm with varying thickness, and can be cut to size to fill large openings in fire-rated walls and floors. These boards are typically used in areas where pipes, ducts, and other large penetrations need to be sealed and are often used in conjunction with an intumescent mastic for the seals, and a paint-like fire rated coating for any exposed batt edges.


When selecting firestopping materials, it is important to consider the specific requirements of the building and the applicable building codes and regulations. In addition, it is important to ensure that the materials are installed by trained and qualified personnel in accordance with manufacturer instructions and industry best practices. Your selection will depend upon the test evidence that is available for a manufacturer's products, and will most likely result in a range of materials from the same manufacturer being used for each case.


Here are some links to the Protecta and Rockwool websites where you can find more information on their fire stopping products:

Protecta:


Rockwool:


These websites provide detailed information on the various fire stopping products offered by Protecta and Rockwool, including product specifications, installation instructions, and performance data. Additionally, they may offer resources such as brochures, technical documents, and case studies to help you make informed decisions about which products are best suited for your specific application.



14 January 2026
Fire door inspections explained for property managers, covering legal duties, inspection processes, common issues, and how Verus Group supports compliance.
23 December 2025
Discover how passive fire protection and fire‑stopping in London and across the UK ensure safety, compliance, and effective fire‑risk management.
by Verus Group 5 June 2025
Verus Group is proud to partner with Thames Hospice, a leading charity providing expert palliative and end-of-life care to those facing terminal illness across East Berkshire and South Buckinghamshire.
by Verus Group 10 March 2025
If you delved into the various facets of fire safety, you've probably encountered the concepts of 'active' and 'passive' fire protection. But what do these terms actually mean?
by Verus Group 4 January 2024
Discover why fire stopping in schools is vital for safety. Verus Group highlights best practices and solutions for protecting students and staff.
by Verus Group 14 December 2023
Learn what fire compartmentation is and why it’s essential for building safety. Verus Group explains how it helps control fire spread and saves lives.
by Verus Group 17 October 2023
Discover the Golden Thread in fire safety and building management, ensuring accurate information, accountability and compliance across a building’s lifecycle.
by Verus Group 9 October 2023
Learn 10 crucial fire door checks that could save lives. Verus Group explains how to inspect, maintain, and ensure the effectiveness of fire doors.
by Verus Group 24 August 2023
Understand the risks of pink foam misuse in fire stopping. Verus Group clarifies its limitations and offers safer, compliant fire protection solutions.
by Verus Group 17 April 2023
Understand the key differences between Rockwool and mineral fibre. Verus Group compares materials to help you choose the right fire protection solution.