Two examples.

Paint

Our builder had previously had a "bad experience" with an eco paint, and so brandished all eco paints with the same tar. We were planning to go with BioPaints for our internal wall paints after a friend having really good experiences with them. We had already decided that while Bauwerk lime based paints sounded fantastic, that they were just too different to convince our builder to use. Our builder still baulked at the idea, as Solver was his usual paint, and we ended up going with the low-VOC Solver Enviroguard paints.

Even then our builder didn't like their coverage and finish compared with their normal range. I, on the other hand, was quite happy with the finish (where the paint was decently applied), and the lack of smell was fantastic.

But using an eco product against a tradespersons advice allows them the upper hand. If the finish isn't great: well, of course it was the product not the application. We painted our doors ourselves, with a very good finish (if I do say so myself!). The next day the builder had placed all the doors upright touching each other (we had separated them all with polystyrene). When they took them to install, quite a few spots of paint pulled off almost all the doors. But was it because of him stacking them together still wet? No, apparently not, apparently it was the paint's fault - it "lacked guts".

Cork floor sealer

We ummed and ahhed about whether to use an eco sealer for the floors. It was going to cost an extra $1000 to do so (for an extra coat and the eco sealers themselves). The cork guy wouldn't guarantee the finish and said that it won't last (having never used the product before as a reference, mind you). But we decided that if we went to the trouble of having low VOC paints, we should go the whole hog and use low VOC floor finishes too.

So, we used the Bio Floor Varnish from Bio Paints. It looks ok to my untrained eye, except for the cork installer's sanding marks in the corners (but of course he could blame the product if he wanted to).

So, how can we use eco products when mainstream tradespeople can so easily blame them for everything that might go wrong?

In the roof we have R1.5 foil bonded with fibreglass batts and in the ceiling R3.5 fibreglass batts with a 50mm gap between them. This takes our roof/ceiling R value to R5.

In the walls we have R1 foil insulation plus R 2.5/3 fibreglass batts (a bit of each), with no air gap as there was not enough space. So R3.5 for the walls.

Find out more about insulation at the Your Home Technical Manual.

View from the north east corner

The Your Home Technical Manual on Glazing says:

"Glazing has a major impact on the energy efficiency of the building envelope. Poorly designed windows, skylights and glazed surfaces can make your home too hot or too cold. If designed correctly, they’ll help maintain year-round comfort, reducing or eliminating the need for artificial heating and cooling.

Windows in a typical insulated home can account for more heat gain or loss than any other element in the building fabric. In summer heat gain through an unshaded window can be 100 times greater than through the same area of insulated wall. One square metre of ordinary glass can let in as much heat as would be produced by a single bar radiator. In winter, heat lost through a window can be ten times more than through the same area of insulated wall."

Unfortunately our budget did not allow us to get the best possible windows - we have single glazing, untinted glass on aluminium frames (the frames are white, which does help with reflecting heat a little). At some stage I would like to get tinting to reduce the UV wear on internal furnishings. We will have to rely on good blinds/curtains/external shades to help regulate our temperature. At this stage I am most worried about letting the cold in on winter nights. We haven't yet decided on window furnishings (it will depend on our budget at the end of the build) so if anyone has good suggestions, feel free to post them here in the comments field.

Our celestory windows should provide a very good temperature balance in our house. In winter they will allow the midday sun to hit our rammed earth wall and store the heat, releasing into the night. Although our ceilings at that point are around 4.5m high, we do have a ceiling fan on one half of that area which we will reverse to circulate warm air that has risen back around the room. In summer they will be shaded and can open to allow heat to move upwards using the stack effect principle.

Celestory windows

Sun hitting earth wall at 8.30am in May

As a side note, all rooms in our house (excluding bathrooms and laundry) have light/windows on at least two sides - following Christopher Alexander's Pattern Language.

Simply building a new house uses a whole lot of resources that would otherwise not have been used. Sure, we could have renovated a house or brought an old house onto the site or even bought a pre-fab house (there are some eco-friendly ones now too). But while those options were investigated, none suited our needs, and we do plan to be in this house for a long time. This is our "forever house".

We also can't afford to go green all the way. The budget for this build is around $250 000, which I think is pretty reasonable for a 4 bed, 2 bath house. I'll do a breakdown of costs in a later post.

Another reason for the "semi" part of the title is that it's really hard convincing builders and other tradespeople that eco friendly options are good. We sometimes manage to convince them, but other times they get their own way.

We have two 5400 gallon poly tanks (24 500 L each) for washing and household use water, and we are purchasing a 3000L stainless steel tank for drinking and cooking water. The poly tanks were about $2100 each from the Toowoomba Ag show last spring, and the stainless steel tank will be around $1600 from Stainless Rainwater Tanks in Brisbane. Some people think we're mad spending so much on a tank, but there's been a lot in the media recently about phthalates in plastics and possible health problems, and so we figure a few hundred dollars isn't much to possibly safeguard our family's health. In any case the tank will still be worth quite a bit in scrap metal at the end of it's very long life (and a 25 year warranty is pretty long life).

Our house faces north, meaning most of our living areas have northern windows. The eaves are large enough to shade our northern windows all day during the hot summer months, and will let the sun and warmth in in the cooler winter months.

Our floor plan is shown below (some changes to internal walls and windows were made after this plan was drawn up):

Over the central living area we have high celestory windows that will allow the winter sun into the house. The high ceilings in this area (4.5m at the highest point) allowed us to have a small loft above the pantry (which I think now is one of the coolest areas of our house - thanks to Jayn our draftsperson for the suggestion!).

VIEW FROM THE NORTH-EAST CORNER

On the south wall of this central living area, between it and bedrooms 2 & 3 we have a 30cm rammed earth wall. This earth wall, along with our concrete slab, gives our house a great thermal mass, which should stabilise the temperature in our house all year round.

THE RAMMED EARTH WALL BEFORE ANY OTHER BUILDING HAD STARTED

The rammed earth wall is a beautiful feature of our house and is stunning. And we don't have to paint it!

I hope our windows don't let these design aspects down - but more on windows in another post.

I did a lot of research into our hot water options. You're not allowed to get electric hot water systems anymore, so that cut that option. The remaining options were: gas, heat pump, and solar.

Gas was appealing due to the instant and always available hot water. But we would have bottled gas, and several people warned us that gas prices were going up pretty heftily soon. One friend has gas hot water and say they go through a bottle ($120 or so) every 3 months for a 2 adult 2 kid family, but they are super careful with how much they use and adjust the temperature all the time. One salesperson said his family also go through a bottle every 3 months for a family of 2 adults and 3 teenagers and many visitors every weekend. Not sure how both families could be using the same amount of gas. Gas is the cheapest system though, a recommended system would be around $800 for our family of 2 adults 2 kids.

Heat pumps seem to be the default replacement for electric systems. They work like a reverse refrigerator - drawing heat from the ambient temperature. They are supposed to work at up to a few degrees below zero. But I didn't see any real proof of how they work in our climate here on the Granite Belt. One salesperson said they wouldn't work properly here because of our altitude, but I couldn't find anything that backed up that claim. The big negative about they is that they apparently sound a lot like an air conditioning unit - not that quiet. And when they can't get enough temperature gain, they just use electric boost.

Solar hot water was very appealing. But even more confusing there are many different types of solar hot water, and of course when you talk to the salespeople their system is always the best on the market and they dis all the other types of systems. My research led me to believe that the evacuated tube systems would be better in our climate than the flat plate collectors. The evacuated tube systems work even in Canadian winter conditions, so I believe they should suit our conditions here.

Solar hot water can be boosted with either gas or electric, but gas would be several hundred dollars more expensive and noone seems that keen on them. Many people with evacuated tube systems just turn off their electric boost until they need it (apparently after 2 or 3 days of very cloudy conditions), otherwise the boost might come on every morning before sunrise. But do your research, as the water needs to be hot enough to kill some bugs that can breed in not so hot water.

So, we decided on evacuated tube hot water, and we're going with AMAC in Tenterfield, as noone supplies evacuated tubes locally [update May 2010: it appears MWF and Aqua Rural are now selling Apricus systems locally].

We are building a new house, and we're trying to be as green as we can afford to be. But we're also limited by how much time we have for research and how hard it is to find reliable and up to date information about green alternatives.

When asking around for greener alternatives mostly we are met with "oh, that's way too expensive". But often, when you dig deeper we find that that's not true - maybe it was in the past but it's no longer the case in many instances.

So, here we are. House building started in December 2009, and should be finished sometime in May-ish 2010.

Join us in our journey, or give us some suggestions to help us make decisions.