Monday, 25 March 2013

A good roof overhead ~ part 1 ~ getting started

~ This article, originally published in January, is part of a series.  I have duplicated it here to make it easier for readers to find their way back and forth to companion articles. ~

25th January 2013:
Our friends across the road are having their roof replaced.   I enjoy construction so have been taking an interest in this big project.  Our house directly overlooks theirs so we have an excellent view of the proceedings from our balcony!

Yesterday the big day arrived when the roofers screwed the first new tiles into place.  Here they are working out placement:


Getting to that point required a great deal of preparation.  Only the day before John was up on the roof re-checking measurements for the placement of solar panels.  These will be snugly fitted in among the other titles:


The old corrugated iron roof had served its turn well for many years but needed to be completely replaced.  It would be a big job: 


Invisible from below, but clearly seen from above, rust was steadily eating into the corrugated iron: 


Living next to the sea is wonderful in many ways, but salt carried by the sea air rusts most metals relentlessly, so rust-resistant materials are important.


Choosing the new roofing material:
It was a big decision to re-roof in tiles but replacement corrugated iron was not considered due to its short life span in the salt laden sea air.  What had worked reasonably well in the past would be less satisfactory in the future as this roofing material is now manufactured thinner than it used to be. 

In the tile department, ordinary terracotta tiles had to be rejected as these are a great deal heavier than roofing iron and the house was not built to support that weight. 

After a lot of research and careful consideration John chose these ones made of a synthetic resin: 


These fit together neatly as you can see here:


They are screwed into place so are nice and secure as well sturdy - they don't mind being walked on (with care!) and are not slippery.

Traditional terracotta tiles are attached to roofing battens by wires.  In the event of a serious earthquake these attachments can fracture and tiles come loose, as happened to many traditionally tiled houses in the Christchurch earthquakes.  Here is one such casualty:


...So on this point the synthetic resin tiles chosen seem to be a more secure product.

Making new battens:
Once John had decided on tiles many new timber battens were required.  John milled these himself.  They are made from Canadian Oregon, which is very stable and straight-grained.


The patterns in the wood-grain are handsome:


They were milled from big old beams from a building which had been damaged in a fire.  Underneath the charring most of the wood  in the beams was fine. 

The arrival of the tiles was another Big Day.  Here they are in their crates outside the gate, which was as close as the carrier could bring them to where they needed to be stored. 


In order to be moved any further they had to be unpacked.  Here you can see a portion of them lined up next the the battens:


And yet more...


After this delivery there was a wait of several weeks until the roofers and scaffolders were available.  

The roofers hadn't installed this sort of tiles before, and indeed John does not know of anyone else in New Zealand who has used them, so when the roofers first arrived they took their time working out exactly how to go about the job.


John climbed up to join in the discussion.  There he is on the right:


In the image below John is rolling up lengths of butynol, a flashing material.  Flashing takes a number of different forms and is a vital factor in a weather-tight house. 


Once the roofers had worked out how to tackle the tiles the flashing materials were quickly put in place and the tiles went on smoothly row by row.  You can see the black flashing paper sticking out at the sides:


The tiling of first section of the roof was quickly completed and the roofers left the site to the scaffolders.  The scaffolding is a vital component of what turned out to be a lengthy and complex job.  I've written more about this in the following article (see below).


This is what the site looked at at the end of Day One:  


Today the roofers got to work on the right hand side of the top level, while the scaffolders completed the rest of their structure around the house.  It was all go:


And then after knock-off time it was very quiet!  A lot was achieved during the day! 


I have covered the advertising sign on the front of the structure with a maple leaf as I reserve the right to convey this sort of thing according to my own choice.

Further technical information:
The supplier of the tiles is Chinese.  You can find their website here:
The number of slates / tiles required:
Roof area is 176 sq meters
Coverage is 11.1 per square meter
1953 needed assuming solar slates were NOT installed.
2400 plus 48 solar slates were purchased to ensure that there will be plenty to hand for any additional work that might be undertaken in the future.

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