ROOFING, CLADDING & INSULATION
October 2019 • BuildingProducts.co.uk 45
However, there is
another factor in fire
safety, fire resistance. This
measures the period that a
particular building element
can resist exposure to a
specified fire load whilst
maintaining its form and
With a melting
temperature of more than
1,000ºC, rock mineral wool
is able to preserve the integrity of the structure. It also minimises
the transfer of heat from the source (the fire) to the other side of the
building element. As a result, it is better suited to applications where
fire resistance is a requirement.
As well as contributing to fire safety, mineral wool is highly
absorbent which makes it ideal for acoustic applications. An acoustic
mineral wool insulation will trap sound energy between the individual
strands and turn it into heat energy. This prevents sound passing into
adjacent rooms or reflecting back as echoes.
While our tests have demonstrated that both glass and rock mineral
wool perform equally well in acoustic applications in real-world
buildings, there are some applications where one would be preferable
over the other.
For internal walls, an acoustic glass mineral wool insulation
roll offers a distinct advantage. Thanks to its superior tear
strength, the roll can be cut to the exact height of the
wall, minimising the chance of gaps where sound could permeate.
However, in applications where greater levels of fire resistance are
required, rock mineral wool can offer an alternative.
To illustrate how multiple performance factors could influence
your choice of insulation material, take for example two common
retrofit applications within the loft of a standard family home.
If you were simply upgrading the loft insulation, you would
typically choose glass mineral wool because of its superior thermal
performance. If, however, you were converting the loft into another
bedroom, thermal insulation would be required at rafter level but
not within the internal floor. Instead, insulation would need to
provide an acoustic solution to reduce noise transfer. It would also
need to ensure fire resistance to allow occupants on the third storey
to escape should a fire occur.
In most cases, the plasterboard ceiling would not be replaced
during a loft conversion, so because you cannot be certain of the
fire-resistant properties of the plasterboard ceiling, rock mineral
wool would be the optimum solution.
Sustainability is becoming an ever-more important
consideration in construction, not just in the performance of the
final build, but in the materials used during construction. Both
glass and rock mineral wool offer good levels of sustainability and
their insulating properties continue to protect the environment
by reducing energy consumption and carbon emissions of the
buildings in which they are used.
In terms of recycling, glass mineral wool generally
contains more recycled materials due to the availability
of used glass.
The sustainability of both glass and rock mineral
wool can be further enhanced by choosing insulation
with no added formaldehyde or phenols so that it
offers high levels of indoor air quality. With this in
mind, look for the Eurofins Gold Certificate for Indoor
Air Comfort, which recognises low VOC building
products, that can contribute towards the points needed
wool behave in
for BREEAM, LEED and the Well Building Standard.
Glass mineral wool is better suited for packaging compression
as it recovers well and retains its thermal performance. This means
that it is more efficient to package, transport and store prior to use,
helping to lower its ecological footprint.
The margins in today’s state-of-the-art buildings are so fine
that anything that compromises the performance of insulation
should be avoided. By understanding the inherent properties
of rock and glass mineral wool insulation, you can utilise their
strengths to your advantage, ensuring the building performs as it