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Warm Roof Insulation

A warm roof consists of warm flat roof insulation and is an airtight construction, without any gaps.

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HARDROCK Multi-Fix (DD)

Warm Roof Insulation

A warm roof consists of warm flat roof insulation and is an airtight construction, without any gaps. The waterproofing membrane is placed directly on top of the insulation. 

Insulation is generally applied directly on top of the steel, concrete or wooden deck, with a vapour check layer often installed below the insulation – towards the deck – to make sure that no moisture can penetrate the construction. 

This helps keep out cold air and create a comfortable temperature indoors. 1

ROCKWOOL warm roof insulation is made from stone wool and designed to achieve maximum thermal performance. It’s also non-combustible, with exceptional acoustic properties.

Without proper insulation, properties will lose more heat in the winter – resulting in greater energy use to warm them effectively. During the summer, heat will easily come in, increasing the need for cooling.

Table of contents

  1. Why do we need warm roof insulation
  2. Calculator and savings
  3. Why choose ROCKWOOL solutions
  4. Case Studies
  5. Installations
  6. Sustainability
  7. Downloads and resources
  8. Financial support
  9. FAQ
  10. Other relevant applications
Find inspiration, guides and reports

Warm Roof Insulation Products

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Flat Roof Solutions

HardRock® Multi-Fix (DD) Tapered

Non-combustible tapered insulation for flat roofs. HardRock® Multi-Fix (DD) Tapered is a BBA-approved insulation board, fabricated to a fall to provide drainage across a roof.

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Flat Roof Solutions

HardRock® Multi-Fix Angle Fillet

The area between horizontal and vertical interfaces can sometimes be the most challenging part of a flat roof to insulate and seal. HardRock® Multi-Fix Angle Fillets have been specifically designed to create a smooth transition at 90° abutments, for effective flat roof insulation and waterproofing.

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Flat Roofing Solutions

HardRock® Multi-Fix (DD)

HardRock® Multi-Fix (DD) is a BBA-approved insulation board, that in addition to thermal comfort, provides independently-tested acoustic and fire resistance properties.

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Flat Roof Solutions

Acoustic Membrane

Flexible polymeric acoustic layer - Complimenting the acoustic performance of HardRock®) Multi-Fix, ROCKWOOL Acoustic Membrane is a high performance, sound deadening polymeric layer used to enhance the performance of an acoustic roof build-up. An ideal acoustic solution for buildings requiring an exceptionally high acoustic performance, such as schools, hospitals, cinemas, airports, arenas and leisure developments.

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Flat Roofing Solutions

Acoustic Infill

ROCKWOOL Acoustic Infills are sound-absorbing trough fillers for perforated steel decks. This tissue-faced product acts to absorb incident sound, reducing noise build-up, which lowers the reverberation time and creates a quieter acoustic environment.

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Flat Roofing Solutions

HardRock® UB34

Insulation for upstands and parapet walls - Consisting of a dense ROCKWOOL insulation slab bonded to a rigid 6mm exterior-grade fibre cement board, this combination of two non-combustible products provides an impact and weather-resistant insulation solution for flat roof upstands and parapet walls.

Why do we need warm roof insulation?

Warm roof insulation is important because it keeps out the cold air and conserves the heat inside a building. When installed between and above the rafters, it helps to create a warm layer that prevents any air from outside getting in.

As one of the most effective ways to prevent heat loss, it is the most favourable way to insulate flat- and pitched roofs and make the most of the space, both simplifying the design and helping to lower costs. 2

 

Relevant resources
The ROCKWOOL Red Book
Download
The Fifth Facade CPD
Book now
Flat Roof Zoning Tool
Access Tool
Warm roofs are the umbrella generating spaces to live and work.

Kim Brandt

Global Product Manager, ROCKWOOL Group

Calculator and savings

Buildings with warm flat roofs typically use less energy to heat or cool the indoor space, making it a great investment for industrial, domestic and commercial properties. Bills should generally be lower, and the building’s carbon footprint reduced. 

When planning your project, the insulation thickness can be set to almost any specification. Warm flat roof insulation is highly effective – and often a key part of the energy saving potential for the entire building envelope.  

Globally, the average installed density of stone wool insulation for warm flat roofing is approximately 100 – 170 Kg/m3 depending on the type of system.

You should recoup the installation cost within five years, with research suggesting it can save you up to £285 per year on energy bills. (Source: https://energysavingtrust.org.uk/home-insulation/cavity-wall)

Use our ROCKWOOL U-Value calculator to determine the potential thermal performance of your roof insulation. 

 

Learn about energy efficiency
roof insulation, flat roof, bitumen seal, adhesive-friendly surface, dach+holz 2020, bitrock, bitumenabdichtung, klebefreundliche oberfläche, dachdämmung, flachdach, presse, germany, presse, press

Why choose ROCKWOOL solutions?

Our insulation uses powerful stone wool to help keep the warmth inside your building – and block the outside noise out.

When applied above the roof deck, warm roof insulation provides an added layer of protection that retains heat, helping to create a comfortable environment inside. 

Effective for the lifetime of a building 3, our stone wool insulation is quick and easy to install whether you’re working on blocks of flats, schools or other buildings with a flat roof. 

 

ROCKWOOL products give you the ultimate peace of mind:

  • Effective insulation engineered to last the lifetime of a building 4
  • Fire resilient and can withstand temperatures in excess of 1000°C 5
  • Acoustic solutions that reduce noise from weather and urban life 

Effectiveness

As 66 percent of energy consumption in buildings is used for heating, cooling and ventilation6, our insulation helps to reduce this by maintaining an optimum indoor temperature.

 

Robust and durable

ROCKWOOL product structures have no movement when exposed to heat, cold and moisture.

 

Acoustic protection

Sound reduction is also a key feature of our insulation. It can help to absorb and block out noise from urban life and harsh weather conditions.

Find ROCKWOOL products

Case studies

The new Apollo Tyres factory in Hungary was constructed to produce millions of truck and car tyres each year – with high amounts of combustible material on-site.

 

The challenge

The company wanted to boost fire safety for its employees. Reducing energy costs and the building’s carbon footprint was also a major concern.

 

The solution

Architects suggested installing 190,000m² of fire class A1 ROCKWOOL insulation into the factory roof to increase its overall fire performance. The insulation also helped to reduce the carbon footprint and improve interior climate conditions inside the factory for the workers7.

 

Find more case studies
Reference case, Taulov Dry Port, Hardrock, building site, FRI, roof, construction

Installation

Key tips:

  • Before starting, accurately measure the roof space
  • Clear the roof surface of any loose debris
  • Lay the boards tightly with staggered joints8

 

Installation guides for professionals

Sustainability and energy efficiency

At ROCKWOOL, we harness the properties of volcanic rock to create products that are highly sustainable as well as high performing.

Combining the benefits of this naturally abundant material with circular economy practices, our insulation saves around 100 times more carbon in its lifespan than is used in its production and ROCKWOOL insulation can become ‘net carbon positive’ in less than 200 days.

Thanks to the non-combustible nature of stone wool, ROCKWOOL insulation boasts excellent fire protection and does not rely on flame retardants that can produce toxic emissions. Our warm roof insulation also improves health and well-being by limiting noise transfer from external sources.

Environmental Product Declarations (EPDs) are available for all of the stone wool insulation products manufactured in the UK. To request an EPD for warm roof insulation, contact technical.solutions@rockwool.com.

Learn more about sustainability at ROCKWOOL

Downloads and resources

To be updated
PDF
11.2 MB

The ROCKWOOL Red Book

Download
To be updated
PDF
476.7 KB

Tapered Roofing Guide

Download

Download our guides

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Product Documentation

ROCKWOOL Thermal Regulation Guides

More stringent thermal regulations are now in place across the UK, bringing significant changes for new and existing buildings. Download our straightforward guides today

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Product Documentation

The ROCKWOOL Red Book

To help save specifiers’ time and make it easier to identify the correct insulation solutions for facades, walls, floors and roofs, ROCKWOOL has launched the new ROCKWOOL Red Book – a fully interactive guide which provides digital access to technical data, product certification and a wide range of specification support materials.

Financial support

Check the Energy Savings Trust website to see whether there are any financial support schemes available for warm roof insulation.

Energy Efficiency, Key, Keyboard, Button

FAQs

Do you need to ventilate a warm flat roof?
How do you insulate a warm flat roof?
What is a cold flat roof?

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