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In an uninsulated home, the majority of heat is lost through the roof.

ROCKWOOL flat roof insulation provides excellent thermal, acoustic and fire-resistant solutions for both commercial and domestic projects.1 We offer a wide and versatile range of premium-quality stone wool roof products which help to improve comfort and reduce carbon emissions.2



Why do we need flat roof insulation?

As heat rises, most energy loss is usually through the roofing area. Flat roof insulation is an essential tool that can enhance the energy efficiency of a building and reduce fuel costs.

Creating more effective flat roof barriers also offers your building further protection from the unpredictable outdoor climate, including overheating in warmer climates and rain and snow in cooler regions.

From high rise apartment blocks, to residential designs, industrial units, large commercial facilities and schools or hospitals, flat roofs are an integral part of modern building design.

Constructions such as terraces, rooftop gardens, blue roofing with water retention and roof spaces which are used for solar purposes are becoming ever more popular. This growing trend for functional roof spaces brings even more demand for effective insulation, helping to enrich the space available on top of your building.

Flat roofs are the umbrella generating spaces to live and work.

Kim Brandt

ROCKWOOL Group Product Manager

Calculator and savings

Roof insulation is very cost competitive when saving energy consumption overall – and provides a key, valuable investment for the future.

In addition to this, flat roof insulation often has a relatively fast payback time in terms of money, energy and carbon footprint.1

There is no ‘one size fits all’ answer to how much flat roof insulation you’ll require. Since there is usually no limitation to the installation height on a roof, and ‘the sky is the limit’ so to speak, insulation thickness can be adjusted to almost any possible customer specification and local regulatory energy demand.

The average installed density of stone wool loft insulation globally is around 90 – 160 Kg/m3.

You can use the tools and calculators on our local pages to work out the potential cost savings you could make.

renovation, office, office building, gladbeck, gebäude 2, Renovation ROCKWOOL office building Gladbeck, flatroof, installation, Hardrock, Germany
ROCKWOOL solutions for flat roofs are durable and proven by more than 40 years of use. ROCKWOOL flat roof insulation is also non-combustible and will protect you, your building and inventory if a fire occurs.

Kim Brandt

Kim Brandt, Global Product Manager, ROCKWOOL

Case studies

The project

Wilmcote House in Portsmouth, UK, is a high rise, high density housing estate built by local authorities in the 1960s.

The aim of the project was to create an improved environment to benefit the health and wellbeing of residents, providing comfortable, safe and thermally efficient homes for many years to come.

The problem

Residents were not using their electric heating, as it was too expensive.

This was leading to issues with mould, damp and condensation, causing poor living conditions.

The solution

A huge retrofit of Wilmcote House was carried out, using a combination of several products and systems.

This included a ROCKPANEL cladding façade system, and a combination of ROCKWOOL external wall and flat roof insulation, together with a selection of our fire protection products.

Read more about Wilmcote House



Wilmcote House project completed
Before, the residents tended to stay in one room with the heating on and not really use the whole flat. Now, because it is warm, they are using the whole flat – and some have already reported improvements in terms of health.

Loreana Padron

Associate Director, Head of Sustainability at ECD Architects

Sustainability and energy efficiency

At ROCKWOOL, all our products are designed to be both energy efficient and high quality.

We embed our aims and values in everything we do and the products we produce, helping to create functional and sustainable insulation to improve modern living and the environment.

North America green building design and construction using green roofs to save energy, absorb rainfall, and help cool the air during the summer when the humidity and temperature in urban areas is much higher than nearby countrysides. Sustainable infrastructure and buildings.

Financial support

Grants or subsidies may be available in your market. Check local pages and government sites for more details.

Energy Efficiency, Key, Keyboard, Button


How thick should flat roof insulation be?
Do you need to ventilate a warm flat roof?
What is a cold flat roof?