# Forum Home Renovation Roofing  Cost benefit of colorbond 0.42 v 0.48

## DIYwannabe

Hi there, 
           I am in the process of getting my colorbond roof replaced and I recently got a quote back that had separate costings for 0.42 thickness or 0.48 with the cost difference between the two being $2500 for the entire roof. I am wondering what the cost benefit is between the two.  I am in Canberra where cyclones are (hopefully) a non-event thankfully. Any other considerations? 
Cheers 
DIYwannabe

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## r3nov8or

Assuming corrugated / ORB profile, the Design tab on this page indicates the spans that the different thicknesses can go to.  Lysaght®: LYSAGHT CUSTOM ORB® 
The 0.48 means you could use less roof battens, for example.  They also have different wind pressure capabilities. Not sure if there is any other benefit in going the extra thickness. I like roof battens at a max of 900mm anyway, to make them more easily serviceable/trafficable

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## Moondog55

IF you were in a bushfire area you may actually need the thicker roof panel for penetration resistance, better check with your local council just in case
What ever happened to real roofing iron/??/ the old stuff was at least 1.1mm thick

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## r3nov8or

> What ever happened to real roofing iron/??/ the old stuff was at least 1.1mm thick

   I think it all rusted back to 0.42    :Smilie:

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## Bloss

> I think it all rusted back to 0.42

  LOL - actually when I was a young lad (the 'olden days') 'iron' or 'tin' roofing thickness was via gauge - so commonly for corrugated (gal) iron 26 gauge (.47mm) or HD at 24g (.70mm). 24g was a bugger to cut & work with let alone 1.1mm which would be around 18g I think. 
In any case in the ACT I'd not bother - but make sure the roof sub-structure is at correct distances and even on thicker steel stay on batten/ screw lines when walking so as not to crinkle or dent.

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## Moondog55

Hi Bloss.
I was thinking of the "Heritage work " done in Ballaraatt a wee while ago, the gal sheets were very heavy and only a yard and a bit long; they were even manufactured with a turn-up at the top and dimples to stop capillarity and I'm positive they were even thicker than 18 gauge this stuff was "Hot-dipped" even; after the event some  Hm lets just call them "left-overs" made their way to Marysville which is where  I saw them in the middle 80s

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## fishnmick

No Point at all to use .48, unless it's in an area like an exposed verandah and any dents will look unsightly from underneath.

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## Moondog55

I would absolutely disagree. I have seen timbers go through thin roofing iron when driven by bushfire winds.
When we build in the country I would go so far as to line the whole roof with weldmesh to prevent that if I could not get heavy steel roofing, even 0.48 is borderline, I quite honestly was thinking of using spandek as roofing

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## r3nov8or

That's fair enough MD, but if the firestorm can punch a whole in your roof you probably have more to worry about that just the hole in your roof...

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## Moondog55

The old one hour fire rating 
Just needs to keep us alive until the fire front passes
That said I do believe that the continued trend to lightweighting building materials has its limits, you may be better of living in a tent in some circumstances

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## barney118

ALso consider colours as 0.48 is not available in full colour range.

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## Bloss

OP is in ACT - if in the urban area the fire stuff is not relevant despite the 2003 bushfires. If he is on the urban fringe designated as in a fire risk then the local authorities will enforce the correct specs anyway. As to rust - a colorbond or gal roof in Canberra will last 100 years and more - it is a dry low humidity climate.

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