What You Need To Know About Asbestos Super Six

We got some great feedback from our Last Article Asbestos: Still A Hidden Killer 

So we’ll quickly take you through two areas and the things you need to know about asbestos in roofing and fences.

I read a recent real estate article on a decision by the Real Estate Authority of a Palmerston North woman who was ordered to repay expenses and attend a training course, after misrepresenting the possible presence of asbestos in a property she was selling.

Although the decision had nothing to do with not picking up the defect, it seemed like it was more of a communication issue. Either way, not knowing the exact details was the basis for the decision.

We’ve tried to explain this as best we can, so that you can get a really good idea on how you can approach the topic with confidence.


What Is Super Six?

If you’ve ever heard the term super six – It’s actually Hardies Super Six – which is made up of cement sheets combined with asbestos fibres. It was manufactured and sold by James Hardie and used for roofing and fencing.

Asbestos cement was ideal for corrugated roofing because it was easily moulded. It also happened to be cheap, easy to install, durable and conveniently fire resistant … and came with ridge and hip cappings:


Super Six Roofs

They’re pretty easy to identify, they don’t vary too much and look like the picture on the right.


Super 6 Corrugated asbestos sheets were commonly used up until the 1970s as a roofing material in both domestic and commercial buildings. To my knowledge there is no other corrugated cement sheet that doesn’t contain asbestos.

The unsealed sheets will shed fibre over time with age and weather. The fibres are generally washed out in rain water and accumulate in the gutter and other run off areas.

A few years ago they did research in Wellington on asbestos in rainwater collected from super 6 roofing and showed significant amounts contained in the runoff from rain water.

Here is where you should take note:

If the water run off goes directly into the ground instead of the stormwater drains; over time, it will result in significant contamination build up one the ground where it lands or the gutter … and will become airborne if disturbed by wind or cleaning/maintenance or removal work.

Also the moss and lichen ( see image) on asbestos sheets (roofing, cladding, guttering, exterior pipes) actually grow into the surface and weaken the cement sheet structure. And any of that moss or lichen that comes away from the asbestos material, may contain asbestos fibres in their root systems and should be treated as contaminated material. 
If the roofing cracks become brittle with age, rain water will leak into the building and if it contains asbestos, as it dries – again it has the potential to become airborne inside of the ceiling voids and roof trusses.


How to Tell The Difference Between Super Six and HardiFence

The fences to look out for are the ones that look just like the corrugated roofs, they’ve been in use for over 40 years and are from the same Super Six family. The product later became known as Hardifence, which is based on a far safer cellulose system.

Both of the products look dangerously the same and are quite difficult to determine the difference, if you don’t know what you’re looking for.

Which is exactly what this article if for.

Although this type of fencing is not common anymore, it’s still a good idea to know as much as you can about it.

James Hardie stopped producing the material over 1985 and replaced the Hardifence.
features of modern hardifence


The newest Hardifence version is easy to recognise, as it has 5 ridges and most definitely does not have asbestos in it.

The Super 6 asbestos fences have 7 ridges – but just be aware that the older versions of Hardifence without asbestos used to have 7 ridges also.


Early profile hardifence has the same profile as super six(asbestos) with 7 ridges

The early units of Hardifence were prone to break and cracked quite often from the bottom. They were also prone to break around the diamond washer and nut.

Early style hardifence is prone to breakage around the fixing

They soon improved this problem by creating deeper corrugations and got rid of the washer, nut and bolt and put a lot of emphasis into the metal capping to keep the sheets from separating.

Metal capping on hardifence and asbestos capping on super six


If it has fibre cement capping, then it is most likely going to be asbestos.

But if it has a metal capping then it’s most likely going to be Hardifence, which doesn’t contain asbestos.


Asbestos cartoon