Howdy folks, long time no blog :)
Things have certainly been ticking along nicely in the Atamai Eco Village.
Firstly I got proper internet to our site, not the overpriced 3G joke that I was putting up with previously. Now I've got a microwave dish that points to a radio tower on the hill, and I get "good enough" download/upload speeds at low latency ... great for VoIP (internet telephone) which works well.
|You'd have to squint to see the radio tower, but I assure you it is there, right above the "Radio Tower" words.|
We also got our lower rainwater collection tank installed. I really can't get enough of them cranes and diggers ... check out the pics below:
|Check out the size of that tank! 24,000L in case you were wondering. Oh, and I think it weighs 12 tonnes.|
|A a crane used to lift it into the hole. This tank will be buried once it has been given some fittings and tested at pressure.|
They are equipped with a maze of piping and valves to feed our site as well as the neighbouring site. The end aim would be to have a network of water tanks around that will enable all lots in the village to be water self sufficient, in addition to having central repositories of water to use in emergencies and extremely dry conditions which may be ahead of us.
You're probably thinking, ghastly - look at all that concrete! Yea I know, I know. But it is really the best solution if you don't want to see ugly water tanks everywhere, these tanks are one of the few types that can actually be buried because they are so strong. As such they last longer than plastic tanks, and keep the water cooler being buried - some even say the traces of cement is good for you to drink, the cement make the water a wee bit alkaline.
On the theme of water, I installed our 3 stage + UV filter system as shown here:
Note the filter cartriges are not installed in this picture, but they consist of (right to left) a 5 micron filter, followed by a carbon block filter, and then a 1 micron filter before it enters the UV radiation chamber (the top silver pipe thing). This means our water comes out drinkable the other end - hopefully :) ... the carbon block filter is designed to take out chemical and organic contamination such as pesticides which may find its way to our roof surface. The final 1u filter is to ensure that particulates are small enough that they don't shade the bacteria in the UV chamber.
The filters are large enough that you have to change them only once every year depending on usage and how dirty the water is. We are not currently using the UV lamp and boiling the water instead, eventually the UV system will be put on. It is a 100W UV lamp however, so will have to come up with a clever way of ensuring this is only turned on when it needs to be without short cycling it (the bulb hates that!). This particular UV lamp balast is semi smart in that it has temperature feedback and hence does something to enhance the life of the lamp with that information, I haven't worked out exactly what.
Those pressure sensors are currently reading 35 PSI, which is not bad for a header tank system. This is plenty power enough for us and it feels like "mains" pressure. In time I wish to digitally sample this pressure using a digital water pressure transducer - sampling this accurately will give me a direct indication of how much water is in our header tank, an important bit of information when you are on limited water supply. The mechanical gauges above are really only good for telling you ballpark pressures. Not great to tease our 3m of head out of 30m total, even a digital pressure sensor might not have the resolution to do this accurately enough.
The collection of rainwater from the roof for potable consumption is also rather more complicated than it may first seem. When deciding the type of roofing, the most cost effective roofing type that most people will be familiar with is called Color Steel. This product is a Zinc Aluminium alloy coating on a steel base which has been coated with paint. This roofing type is rated (according to standards) for use to collect potable water. However the standards do not incorporate a scale for longevity into the mix. I have been told that Color Steel's coating performance beyond 10-12 years may be compromised require a recoat. This rang some alarm bells for me as it means (at least to me) that over time the water we use for drinking is being lace with the chemical concoction of sun battered and weathered paint.
So off I go to find an alternative. Some of the options I found are listed below:
- Galavnized (Zn) Iron - this is ok but isn't rated to last very long, will end up rusting. Although the rust itself isn't bad for you (Iron Oxide), the water damage caused by leaks might be.
- Zinc Alume (ZnAl) coted Iron - this is the uncoloured version of Color Steel, it doesn't have the paint that wears off over time. This will last a decent swag longer than Galvanized Iron, but some purist might not like the presense of Aluminium in the coating alloy. This is because of the presense of Al in the brains of people diagnosed with Alzheimers disease. However in my opinion this was because of the cookware used, especially for acidic solutions. Although the increasing levels of urban pollution and dissolved CO2 might take us towards having more frequent rains that are acidified - I don't think that the levels of Aluminium that will appear in our water could reach levels where it becomes a problem. I have absolutely no data to back this up, it is just my gut feeling. Hence this is the roofing system I have chosen for our shed, the main benefit of course is its affordability.
- Zinc Alume with Magnesium (ZAM) - this is a kind of ZnAl that has Magnesium added for the benefit of protecting further the underlying steel, so as to extend the life of the roof for longer compared to just ZnAl. Click on the link to get more information about it. Basically the Magnesium acts in a dynamic way to encourage the protection of a cut edge of the sheet. Standard ZnAl doesn't do well when you cut a coated sheet, hence why it has to be made to order in lengths. However any bits of steel that is exposed by cuts or scratches would start to rust, whereas with ZAM this process is halted after a few weeks when a membrane developes over the steel.
- Zinc Titanium (ZnTi) - this roofing type has 98% pure Zinc which is alloyed with Titanium to give it strength and longevity. These roofing systems are touted to last 100+ years, and certainly a contender apart from price. A quote for our 100m2 footprint house with a simple gable roof was topping $50K which is beyond our budget. Also, although Zinc is not really harmful to humans (is in fact beneficial) - some reports account for the rise in Zinc levels in our rivers to high Zinc concentration. It is unclear however that Zinc leeching from roofing is the primary source of the Zinc contamination, as other industrial processes also release this chemical into the environment.
- Copper (Cu) - this roofing material is expensive! Also Cu+ ions has a negative effect on marine life.
- Aluminium (Al) - this roofing material is also expensive, has an even higher concentration of Al in it compared to ZnAl.
- Stainless Steel - this roofing type is interesting and relatively new. We have all found our lives littered with most things stainless steel. It is hard wearing and chemically inert. You can't however use 304 or 316 stainless steel (which is what most pots, pans, spoons etc are made from) on a roof because it is too hard to roll form and requires specialised tooling, and can sometimes spring back. A special breed of Stainless Steel called 445M2 has been created without Nickle in the mix, which is capable of being processed using the same tools for other steel products like ZnAl or Color Steel. However care needs to be taken to ensure no trace of other metals exists on the roll formers when the SS is being processed, to avoid any chance of galvanic corrosion. 445M2 also resists corrosion far better than 304/316 SS, so will last longer. This roof is typically used where salt spray from the sea is very likely to occur, with good results observed for installed roofs thus far. I am still getting pricing for this type of roofing which is proving to be the most promising for our roof, and will update you with the results when I know.
The reason why most people love Color Steel is because it comes in a range of aesthetically pleasing colours. It also mitigates the issue of glare which comes from just about all the other metallic roofing types. However ZnTi does oxidize to a duller texture (some come "pre-wheathered") and the 445M2 comes with a surface pattern in it which helps dull it down a bit. For us, we choose to have the shinier surface and higher price tag in exchange for chemical inertness as well as longevity, with acceptable (and in some circles, desirable) aesthetics.
We did also briefly considered clay tiles - these not only look beautiful they are also chemically inert (if not artificially coloured with harmful chemicals). I found a cheap lot of terracota tiles in Christchurch and was going to ship them up to Motueka. Although the tiles were themselves cheap, desinging an earthquake ready house is very challenging when you have a roofing system that weighs ~50kgs/m2, and this made the entire house cost much more to build with the extra bracing required to hold this roof. We were previously from Christchurch, a city which has recently celebrated its 11,000th earthquake since the Dec 2010 Darfield earthquake. Although it was a difficult decision to make at the time, I think it was the right one not to use the clay tiles.
There is one other novel glass tile which I considered briefly, until it said it was about as heavy as a clay tile. Check it out here. The reason why it is novel is because it combine heat collection as well under it using heat collectors!
There are other roofing types which look great but aren't suitable for drinking from due to natural/artificial chemicals - these include asphalt, shingles/shakes and thacthed.
Since I last blogged, we had Christmas! It was most interesting to find ourselves carolling one night in a ramshackle stable equiped with a brass band, choir and ... (wait for it) ... live sheep. It was packed with about 100 people, and was a fun night indeed. The kids especially loved petting the sheep, who weren't too shy about adding their baaaaas to the singing.
|The owner of the stable also put up quite a show of hand made quilts that she had done over the past years, there were quite exquisite and higly detailed.|
I also had the pleasure of joining in with the Renewables Group during the Christmas parade here in Motueka. The group had painted a giant swiss ball into a representation of the globe, which was cradled in a sheet. We each of us wore t-shirts with messages of recycling, renewing and reusing our stuff and sang as we walked down the main street in Motueka where hundreds of people were in attendance.
|If done just right, the earth is weighless is space and turns at a rate of 240s per degree :)|
|I've never seen so many people in Motueka!! The line of people stretch both sides of the street for maybe 300m?|
Progress with the shed
We decided to add a verandah to our shed so that we would have a good transition from outside, to semi outside, to inside. This will feature on our house as well. Its an architectural concept which seems to have been lost over time but we are absolutely enamoured with it. We have also decided that this veranda will not block light in, so we needed some clear roofing. We could have done it with glass skylights, but in this case for cost reasons we decided to use tinted polycarbonate sheets. The water from this roof will eventually be used for watering plants (or that is at least the plan), so we are a bit more relaxed about potable water applications from this roof in the near term.
As with the main shed, the verandah is constructed as a post and beam structure attached to the shed. The process involves digging holes for the post, securing them in with concrete, then build the rafters and purlins. Theb roof goes one and lastly the deck floor.
|This time we used the village dingo :) ... that is a stand behind machine that can do useful things.|
|You know you're getting a good result when the builders are smiling :) I think in this case Kenny was smirking to Ray about a comment of being vertically challenged ;)|
|You can see the verandah taking shape here with the rafters attached to the posts.|
|My job was to add the macrocarpa decking as seen here. You can see how well that deck gets utilised already, even before it was fully finished. The decking was then oiled with the same stuff we used on our weatherboards, giving it warm glow.|
To end this blog, I thought I might share some pictures of our recent working bee and summer solstice party. It is certainly a joyous thing to be near people who are just as committed (or just as crazy) at trying to live a sustainable lifestyle. They are no longer just our neighbours now, they are fast becoming extended family :)
Until next time, ciao!
Next blog ... the solar panels go up, how exciting!