A quiz about old roofs

[Barry_White]

Interesting info and photos Barry , not overly relevant to the question.

So how many roofs , in New Zealand , were screwed down , rather than nailed down , before 1960 ?

And when did cyclone assemblies first get used in New Zealand ?

Note that the opening question refers to "old unpainted corro iron roofs pre 1960's"
And does not specify any particular place on earth.

cheers,
Jock

Can't really tell you much about NZ Jock but I know they where still using nails here in OZ up until Cyclone Tracey in Darwin, (that really changed the paradigm) they were also using old round head wood screws with lead washers (don't know when that started). Self Drilling and Type 17 screws didn't get invented until about the early 70's.

Don't know about cyclone assemblies in NZ either. Is NZ really in the cyclone belt.

Here is a picture of the various regions in OZ.

[Calm]

clap: :I'mright:

What a guess and it was right. - check out my profile page to get address for the award/present/money/cheque/whatever i get.

Cheers

[Barry_White]

As I heard it and it fits with what's been written. The older corro was 9 corrugations wide, that is, ends with 2 upturns or 2 down turns, to get the correct overlap, adjacent sheets were laid 'flipped'. Because the sheets have two different faces, they will experience slightly different environments in the manufacture or handling process if those processes require a particular orientation of the sheet to feed through machinery etc. Manufacturing tolerances mean that one side may get less gal, or some property that makes it rust faster. Modern sheets are 11 1/2 corrugations wide so could be laid either face up, they might therefore rust randomly or not at all for 700-800 years
Is that true Barry? Is Zinc better than the old gal?

CHeers
Michael

Michael

Not sure on the no of corrugations on the old corro but the current one is 10 1/2 corrugations and they make an eight corrugation sheet for tank makers.

Actually the term galvanizing is the process but it is done with pure Zinc. Zincalume is actually a combination of Zinc and Aluminium . When they first brought Zincalume out they said it would last four times as long as gal but they were then saying in areas inland would double that.

Interestingly they will only give you a maximum of 25 year warranty to perforation and that comes with quite a few strings attached to it.

All other comments I would have to agree to.

Calm

BTW you should read the heading for the Quiz Forum and the prize is the glory of answering and participating

[Manuka Jock]

Bazza , we get about one cyclone a year , generally up north .

Can't remember exactly when we started using self drillers mid 70s maybe ,
and type 17s , dunno , but battery drills have spread them around .
With the advent of roofing specialists , we chippies don't do a lot of it these days ,
thankfully , hauling longrun is not my cuppa tea anymore .

[mic-d]

Michael

Not sure on the no of corrugations on the old corro but the current one is 10 1/2 corrugations and they make an eight corrugation sheet for tank makers.

Now I'm not sure either, I counted nine on the old stuff, but if I couldn't count the new one to 10 1/2 then who knows?

Cheers
Michael