Understanding Rust and Resistance

When oxygen and water reacts with metal
it forms a compound called an oxide.

With iron it forms hydrated iron oxide, or rust.  Rusting cannot occur without both water and oxygen. Water helps iron react with oxygen by breaking up the oxygen molecule.  

During the initial stages of rusting, iron decomposes into other chemicals, because of a reaction with oxygen. These chemicals lose their water to make even more iron compounds. 

The sum of all these chemical reactions makes the rust flake, so it falls off the iron and exposes new iron, which can then continue the deterioration process.  

This weakens the structure of the metal and if allowed to proceed unchecked, can cause the metal to fail.

Salt (chloride) and by extension, salt water, accelerates corrosion and the rusting process.  

Our Caribbean islands are subjected to continuous ‘salt blast’ or salt impregnated winds.

It’s therefore critical that we do all in our power to reduce or block this corrosion and its sources from inflicting deterioration on roof sheeting and exposed steel.

In the case of roofing, ECMIL recommends and supplies coated Colorbond® Steel which provides considerable protection and efficacy from the elements, which create an ideal environment for rust.

This is achieved through enhanced corrosion resistance, a pretreatment layer to improve the adhesion of further coatings,
a corrosion inhibitive primer baked onto the surface and a top coat, baked on, to provide resistance to chipping, flaking and blistering.

We also supply a remarkably reliable partner and industry standard in Zincalume® steel, a premium metallic-coated steel product that consists of 55% aluminium, 43.5% zinc and 1.5% silicon, by volume. However the entire coating is about 80% aluminium. 

The coating gives it a lifetime of almost four times that of galvanised steel and is lightweight, with edge protection, is non combustible and is entirely resistant to termite attacks, making it ideal as a roofing material.  Zincalume® is also a tried and tested high performance steel recommended for the collection of drinking water. 

It is to be noted that design plays a major role in rust resistance by utilising reasonable roof pitch, any building can shed water more quickly than its less inclined counterparts.  
The less water exposure
the slower the deterioration.

From foundation to columns, beams and walls, consistency of mix in concrete and block work protects the supporting steel from ‘rot’ over time.  If the basis of a structure exposes gaps, cracks or poor casting, moisture, oxygen and salt blast will find there way into the substructure of any construction, in turn, often destabilising an entire building.

It is therefore imperative that :

  • a seal is made with an adequate depth of concrete to supporting steel.
  • Concrete is of such moisture resistance that penetration is not
    a high risk.
  • Rebar and welded mesh ends are adequately protected, especially in columns, beams and slabs.
  • Construction designs ensure that water is removed from the outer ‘skin’ of the building as quickly and conclusively as possible, thereby reducing the puddling or soaking.
  • Surface resistance is regularly checked and updated to reduce deterioration.
  • Avoid mixing qualities of steel. 
    There are many offers of cheap steel products and not all steel is reliable.  
    Only buy from reputable resources, who, on request, can justify the quality of their products.

At ECMIL, knowing and understanding our materials has always been the key to our regional success is supply and support to
an active and ever evolving construction industry.

Call your sales representative today

and begin the process of securing your investment, protecting
your property, storing rainwater, strengthening walls and supports, insulating your roof, reducing radiated heat, tightening your fixings and rerouting flood and rainwater to a safe place,
away from your building.


Don’t let the ravages of rust, sun, wind and rain
degrade your hard work.


Contact us and find out why
we are the Steel of The Region.

NB. This article is for general information purposes only and is meant as an incentive to the reader, who should then research and seek advice from their architectural and construction professionals to confirm that the ideas expressed are possible within the building codes of their territory or within the limitations of their home's architecture. ECMIL only recommends their own products and third party products which they supply, as part of their company's roofing solutions to customers.