We are in!

Oh gosh, where did 2013 go?

So much has happened this year it is hard to fathom the amount we have managed to achieve, and yet more what we still need to achieve. We broke ground at about April 2013 to build our house. The build progressed for better and for worse with many testing and memorable moments. Just a week before Christmas 2013 we moved in. The house isn't quite finished, but it is liveable, comfortable and a "tad" more spacious than our 25m2 apartment which we have lived in for the past year.

I know what you're thinking, 25m2 sounds like pure torture, especially with two young children. But instead we have come through with a great sense of achievement. The small space taught us a lot about space optimization and efficiency. We used loft beds to increase the space in the room and plywood sheets to partition the room into a kitchen, dining, bedroom and lounge, with the wardrobe under the main queen loft bed. We had a hose coming into the unit as our kitchen tap, and a bucket as our drain which was used extensively to irrigate the garden. We had a plug in electric induction hob, a microwave and a convection oven to cook our meals - we had numerous dinners with interesting seating arrangements with our many guests, it was actually quite an enjoyable experience. We learnt how to operate in each others personal spaces and felt more connected.  When we came to the end of that adventure our new house seemed larger than life. But alas, we can now concentrate on building the rest of our lives.

In the mean time, I'll fill you in on what's been happening.

House Build


When I left you last I mentioned that there were dark clouds looming over our 2nd hand joinery, and indeed that was our costliest issue on the build. We were trying our best to salvage building materials from post quake Christchurch, but our attempts were met with resistance from our local council. Despite passing our initial house plans detailing this joinery, they weren't happy for us putting them into the build without first getting them certified.

Note that these doors and windows were double glazed aluminium joinery and in pretty good shape when we got them - they came out of a relatively modern house. However it was impossible to find a professional joiner who would recertify the joinery because they are basically accepting liability for the next 15 years on something they didn't produce. Even the original manufacturer in Christchurch were reluctant! I can understand the council not wanting to take on the liability either, but this left us between a rock and a hard place.

We finally decided to swallow the bitter pill of dumping our 2nd hand joinery in favour of new ones. We made this worth our while by changing the window and door design configurations that constrained us previously. This eased the bitter taste.

Our excellent joiner Wayne at Fisher Aluminium reconditioned two of the doors up to a standard he was happy to certify. He also convinced us to get French doors to our main north area instead of the bottom sliding Bifold doors. This was mainly because French doors have simpler hinge mechanisms and no problematic rollers to deal with in the future.
The French doors have been installed, as well as the clerestory sliding windows above.


We spent quite some time wondering what kind of linings we were going to have on the inside of our house. The main options for walls and ceilings in most typical builds is to use plaster board (or Gib board). Although it is cheaper to purchase as a raw material and easier to install, plaster board requires extensive finishing work such as stopping, sealing and painting.

The alternative considered and subsequently decided on was plywood. We used grooved ply on the ceilings (gives it a more tongue and grooved look), and knotty grade ply for the walls.We considered this combination for several reasons:
- we already needed to have plywood on many of the walls that would house future Adobe mud bricks.
- Plywood is stronger in bracing strength than plaster board (made as a paper gypsum sandwich)
- as cash flow was starting to get quite tight, it allowed us the flexibility to move into the house without first having to expand on the cost of finishing it now.
- it was a cheaper overall solution.

Here are a few pictures of the linings ...

Floor finish

The polished concrete floor turned out to be quite dazzling, despite its relatively cost effective price of around $50/m2 including the colouring.
The advantages:
- good thermal coupling between the house and the floor which facilitates passive solar gain
- excellent thermal conductivity for when the floor is heated using the hydronic underfloor pipes
- very easy to clean using low tech tools ... ie. a soft bristled broom and a dust pan
- looks great

The disadvantages:
- you might have to wear slippers or socks when the floor is cold (although really nice with barefoot on a really hot day!)
- the floor is very slippery when wet, especially when wearing said slippers
- we have noticed the floor has chipped in several places, we aren't entirely sure why.
- very shiny (not entirely to Katie's liking)

Our floor was not ground down to expose the aggregate, that would have cost around $85/m2 and we may have lost a lot of that nice earthy colour we added. Overall we are happy with the results.

Below you can see the kitchen before it was populated. 

Rayburn Cooker

As you can see above, we managed to move our Rayburn solid wood cooker into position on its brick plinth. This was done with the help of Rob and his engine lifter. That oven is at least 400kgs!

This oven was purchased 2nd hand from Queenstown and is about 20 years old. The previous owner took really good care of it and it looks immaculate. Like most wood cookers however, learning to cook on this thing requires a bit of a skill. This is quite unlike the fancy temperature controlled settings on a modern oven. We purchased this primarily because we wanted a solid wood heater for our underfloor heating system (this one has a 15kw wetback), as well as means for cooking using locally available fuel which is relatively abundant around our area. We aren't yet giving up on our modern gadgets as we are likely going to be cooking on the electric and/or Biogas hob during times when the oven is not required, such as in summer when there is usually surplus solar energy or Biogas generation. We currently use our little bench top convection electric oven,  will continue with that until the Rayburn is ready to fire up.

Adobe Mudbrick Laying

We designed our house with several walls capable of being lined with Adobe Mudbricks. We have the option to do this later, however the kitchen wall needed to be done before the Rayburn cooker was installed. Katie and I undertook to the creation of this wall, with a brickie showing the ropes on the first day. Here are the steps we took.

First of all we acquired the bricks and the earth mortar from Verena Maeder at Solid Earth in Nelson. She makes the bricks on site using locally garnered materials. The bricks are placed on the brick table which has a bath tub in it, used to wet the bricks before they get laid.

Wetting is required to make the bricks bind better to the earth mortar when it is laid, so that cracks don't appear. The bricks go into the bathtub sequentially and a pipeline is created where dry bricks go in one end and wet bricks come out the other - this gives the bricks some time to sit in the water to soak up before getting used.

Once the bricks are wetted, they are removed and ready for laying.

A bed of mortar is placed on the previous course and built up so that the top of the bricks align up with the string line giving the straight horizontal lines.

While checking against the string line the bricks are also vertically aligned to ensure a flat-ish looking wall. Adobe mudbricks are quite forgiving in this regard and any imperfections come out looking like crafted art pieces - at least that is our official line ;)   An expert brickie might not agree!

A liberal spread of earth plaster is placed between the edges of the bricks to join each brick to its neighbour.

After every two courses the bricks are tied back to the studs in the timber framed wall using brick ties. A geo mesh grid is added to further allow the brick to bind cohesively to the brick ties. This gives the bricks a good coupling to the timber frame wall required for a seismic event. The timber framed wall is braced with brackets at the tops and bottoms of the wall studs, as well as having 9mm plywood across the wall. Here's hoping this will be good for that magnitude 8-9 Alpine Fault event we will likely see pretty much tomorrow in geological time frames!


Being pretty short of cash at this stage, we were quite prepared for a modest kitchen. Some weeks back, our builder turned up with an old 70's kitchen which he had pulled out from a renovation job. He was about to take it to the dump but rightly decided to give it to us instead ... thanks Kenny!!  "It's sweet-as ... bro!"

We used the cupboards as the base units with some flooring strand board sheets to make up the bench tops. We had some old vinly sheets lying around which we cut up and placed on the top of the counter and voila ... instant kitchen. We also acquired a 2nd hand sink and bench which we are using as our main sink. We are quite happy with this result.

The fridge looking box on the right is actually another freezer which I have converted to become a fridge. My previous attempt was for a chest freezer but many of my critics said they would find it difficult to get used to that - so I converted an upright freezer this time with another controller. With both of these freezers running I'm currently averaging about 350WHrs/day (128kwhr/year) at steady state, which I think is pretty awesome! This is with using the chest freezer at -10 degC with the drawer at about 5 degC, and the upright is operating at about 7 degC. 

Fire sprinklers

After much consideration, we decided that the home sprinkler system cost of NZD$8000 was entirely justified and was prioritised for installation.

A domestic home sprinkler system isn't as expensive as a commercial installation because the building code relaxes requirements and allows plastic pipes (instead of metal) and is generally a less stringent system. However, the system is still effective enough to significantly reduce the probability that the house will go up in flames, and will greatly reduce the cost of damage should a fire break out. Another great advantage of sprinkler systems is that they consume much less water than waiting for the fire engine. This matters greatly when you are on a rural property without reticulated town water supply. If you are in times of drought where the likelihood of fires are highest, we can be sure that a sprinkler will put the fire out with the least amount of water. The local council requires 40,000 litres of water on stand by for a typical rural house for the purpose of fire fighting, a sprinkler system reduces this requirement down to 8000 litres. However seeing that we share our fire tanks with our other Atamai neighbours, that wasn't much of a saving for us.

The implications for resilient design around risk mitigation and water conservation has become of great interest to the village developer. They are looking at means to making this more widely adopted by others intending on building here at Atamai. 

The fun part of the installation is the testing of the system. Here is Kerry from Hays Plumbing setting off a test sprinkler head with a butane torch.

Each head has a specified radius spray of 2.5m, so any span greater will require an extra head. The heat sensitive part of the head is made out of copper and is soldered with low temperature solder which mechanically holds the water in the pipe. When heat is applied the solder melts and the head pushes out to enable the fire eating spray.

Our sprinkler heads are concealed with a painted copper cover which also has mechanically soldered connections. When heat is applied here, the cover drops off and the sprinkler head pushes through.

The sprinkler is the white cover on the left

Solar Water Heating and Central Heating

We have chosen to go with a  two tank system for our central heating and domestic water heating systems. The domestic hot water system is heated using a solar collector and a 180L mains pressure tank. This tank size matches the evacuated tube system I found 2nd hand some months ago. It is also capable of heating the water electrically with two separate elements. There is one located at the bottom of the tank which can be used when a dump load is required for the PV system. The other is located 1/5 down from the top so that a small amount of water can be quickly heated if there is absolutely no hot water in the tank and a shower is required. I'll probably end up making a timer relay or one-shot relay system to work this later on.

Just this week, we got hot water flowing out of our taps for the first time in 1.5 years. It is very satisfying to get your hot water from the sun, and we are constantly trying to work out how we can best utilise the free energy to lower our power bills further. For instance, we can use a pre-warmed water to boil hot water on the jug - this wouldn't make sense if the cylinder was heated with electricity, but with solar as a pre-heater it does.

There is a small circulation pump that has to run for the energy from the sun to be transferred to the tank, however this consumes much less power (50W, running non-continuously) in comparison to a heater element. The controller is set to turn on the circulation pump only where there is a temperature differential of 12 degC.

The solar tank will also have a circulation loop to the central heating tank (not installed yet). A solar transfer controller can be programmed to draw heat from the tank heated by the Rayburn stove in winter when heat is lacking in the solar tank, but in summer the solar tank can be cooled by transferring the heat back to the central heating tank - this requires the programming logic to be reversed and threshold readjusted. Even after heating the solar tank for 1 day, the pipes coming out of the bottom of the solar tank are too hot to touch! and were reading in the region of 65 degC!

That's it for this blog. I just had my solar PV system hooked up yesterday and we will go live to grid injection soon enough. I have plenty to do with my battery system before that becomes a live backup as well - that blog will be next, I'm really looking forward to it ;)

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