Durability
The chemical process, which causes steel to rust, can only occur if moisture is present to
enable the reaction to take place. Like almost any natural material (e.g. an Iron Age body
in a bog, or a fly in amber), steel will last almost indefinitely, provided it is maintained in
favourable environmental conditions!
Protection of LIGHT GAUGE STEEL
As a first line of defence, Fusion always insists that their system is built with a cavity
between the Fusion frame and the outer skin of the building. This means that any water
that may penetrate the outer skin can drain away in cavity behind it.
Fusion Light Gauge Steel is coated with a galvanised layer of zinc or zinc/aluminium.
Research by the ‘Steel Construction Institute’ has shown that light gauge steel maintained
in a ‘hybrid’ environment can have a design life of in excess of 200 years.
Hybrid Frame Construction
Fusion’s primary protection method is the creation of a dry environment - referred to as
‘hybrid frame’ construction. This involves creating a wall where the combination of
temperature and humidity, within the zone of the Light Gauge Steel frame, is maintained at
a level, which prevents any risk of interstitial condensation.
The insulation that is built into the Fusion frame has been designed in to eliminate the risk
of any build up of moisture due to interstitial condensation. This has been modelled over a
very wide range of possible internal/external temperature and humidity conditions.
Hybrid Frame principles have been used in construction of Light Gauge Steel structures
since the early 1980’s. To date, there have been no durability issues reported on any
structure.
Protection from Moisture
All joints between Fusion panels are carefully sealed – primarily to reduce air and heat
loss, but also as further protection against water penetration.
Walls are Vapour Permeable
The Fusion system is additionally effective in guarding against the risk of condensation,
because the insulation used behaves similar to a breathable rain jacket. Water vapour from
within the home can pass out through the wall, but liquid water on the cavity side cannot
penetrate the insulation. The wall ‘breathes’. In practical terms, this means that the Fusion
system does not rely on a vapour barrier to prevent moisture getting into the wall structure.
It was damage to vapour barriers, which formed the basis of the infamous World in Action
documentary, which damaged the reputation of timber frame in the 1980’s.