Sunday, 12 August 2012

Corrugated Iron



Corrugated iron is sheet iron that has been folded to created bends that increase the strength and rigidity of the metal. The sheets are put through a hydraulic press that moulds the sheets into the required shape.

Corrugated iron has been a very important material in the development of New Zealand building. It was first introduced into New Zealand over 150 years ago. Corrugated iron is usually galvanised (both sided treated with zinc) which helps to prevent it rusting, which is good for New Zealand as we are surrounded by sea. It was first used in New Zealand during the gold rush period as buildings were needed to house people but they wanted easy and cheap materials to construct the shelters. Corrugated iron was perfect for this as it is lightweight which makes easy to work with and is weatherproof. Since then Corrugated iron has often been used in rural settings as it wasn’t too heavy to carry out to the farms (they didn’t have helicopters back then) and it could easily be re-used on other buildings.

From the early 20th century it has mainly been used as a roofing material. Though Corrugated iron is staring to interest designers as well; it not only does it come in a range of colours but is also staring to be used as an interior feature, such as sculpture or a digitally printed surface.

New Zealand Sculpture Gumboot 2000 By Jeff Thomson


A bathroom with corrugated iron wall panels for texture and aesthetics.

In construction terms corrugated iron has many uses, such as roofing, wall panelling, base for laying concrete and water tanks.

It can be very noisy depending on the weather conditions, when there is heavy rain, hail or snow this can be very loud on the metal surface. Also, if it is not securely fixed to the structure it will flap in the wind as separate sheets are light weight. Domestically blanket insulation is often used under corrugated iron to help with sound control, as well as temperature and reducing condensation. When designing the building you have to take into account that metal is a very heavy material on mass and depending on the size and thickness of the corrugated iron, the buildings structure has to be strong enough to support the roof.

A kit home designed by a small company, Ral Homes.


Corrugated iron is usually galvanised, which means it is treated with zinc to stop the metal from rusting, it is an anti-corrosion seal. It is the best kind of roofing to use in places with extreme weather conditions; it holds up against intense sun, heavy rain and even hail storms. It is often used in hurricane prone areas as it isn’t damaged by the strong winds. It is one of the most fire resistant of all roofing materials on the market.

Corrugated iron has a life expectancy of 50 years, as long as it is treated correctly and properly installed. It should be cleaned regularly, depending on the environmental factors the amount of cleaning may need to be increased. If you live by the sea corrosion will be an influential factor, make sure you have galvanised iron, therefore the zinc will be corroded and not the iron. To decrease the rate of corrosion there are sealants that you can apply to the roof to increase its durability.

An old water tank from rural New Zealand


It is attached using screws and when being laid out on the roof the valley of the corrugations should always be vertical, therefore the rain will be able to run down into the gutters. When over lapping the sheets, the standard over lapping is 1.5 corrugations, that way it will stop water from entering and create a weatherproof seal. You must also be careful not to stretch or damage the material as this will influence the weather resistant properties. You can find more installation tips at- http://stratco.com.au/products/roofing_walling/types/corrugated/cgi.asp

At a building site corrugated iron is should stay dry and be kept off the ground. If it does get wet, dry if off and leave it out in the open to air, make sure it is dry when being used.

Corrugated iron is sold per lineal metre and the prices change depending on the width of each corrugation, and the lengths that you want it in. Depending on the amount you require, corrugated iron can be delivered in sheets or in rolls of up to 10metres.

I got a quote from www.roof.co.nz and for their 0.40 Corrugated iron Galvanised 762 it was $14.85 per lineal metre + GST.

Some Suppliers in New Zealand are:

By Alice Perry


No comments:

Post a Comment