Mar 8, 2015: Form Follows Function

As we continue to glide comfortably towards a hugely successful completion of one full year of living in and monitoring the performance of the Greeny Flat we are working on plans for a little celebration to mark the occasion on Earth Day (April 22nd, 3-7pm). Meanwhile, we’ve been receiving a lot of interest and positive feedback on the progress of the experiment. One issue that comes up regularly relates to the look of the Greeny Flat which I thought was worth addressing in depth.

The ‘Galvanised Iron and Plywood Look’

At a Southern Highlands Green Drinks event this week I was chatting with Ian Scandrett, one of our local councillors, about the need for compact, energy efficient, accessible and affordable housing. We both agree that there is a huge opportunity in this area where house prices are being pushed up dramatically by the Sydney market and the options for single people, young families, pensioners, in fact anyone on a moderate income, are severely limited. Clr Scandrett is a huge proponent of ‘compact housing’ and, when we were discussing the benefits of the Greeny Flat, he made a comment something to the effect that, ‘it’s great if you like the galvanised iron and plywood look’. I pointed out to Clr Scandrett that our use of galvanised iron cladding on the exterior and plywood lining on the interior were personal choices that have very little to do with the energy performance of the Greeny Flat.

One of the great things about writing a website versus writing a book is that, using a free tool called Google Analytics, I can see how many people have viewed our site and which pages they have visited the most. I find it interesting to note that the Gallery Page is by far the most visited after the Home Page. This tells me that a lot more people are interested in what the Greeny Flat looks like than in how it functions. While this is not surprising, since something like 6 out of 7 people are guided by their emotions (i.e. how something looks or feels) rather than by their intellect (i.e. how something works or functions), it does make me realise that I need to explain a bit more about why we chose the materials that we did.

Why Galvanised Iron?

As you have probably already noticed from the photo above, one of the most eye-catching things about the Greeny Flat is the galvanised iron cladding on the exterior walls. This was chosen because it helps us to meet a number of our Goals.

  1. Low Maintenance – one of the things the client for the Greeny Flat (my mother) was adamant about was that there should be no paint on the outside of the building. Over the years my parents have owned a number of houses that had paint on all of the exterior walls, windows, and trim so they are well aware of the tedious work and high cost involved with scraping, sanding, and repainting the exterior of a house. So Mum chose to solve that problem by having no paint on the exterior at all. This immediately limited our choice of exterior cladding materials to either masonry or metal.
  2. Energy Efficiency – obviously, with our goal of being Energy Positive, we were very keen to make the Greeny Flat as energy efficient as possible. While I love the look of mud brick and rammed earth, they offer very poor insulation for our cool winter climate. Standard brick veneer is an insane way to build houses for our hot summer climate because the bricks absorb and hold heat on the exterior and prevent a building from cooling down at night. So masonry was out for us leaving metal as our choice for the exterior which has the advantage of rapidly releasing heat after the sun goes down. We researched various types of metal cladding (some that look like weatherboards) but decided that we really like the durability, low-maintenance and clean look of corrugated metal cladding.
  3. Comfort – metal cladding has the advantage of being light weight which means that it does not hold heat. So the corrugated cladding helps to keep the Greeny Flat cool during the summer. Originally we chose to use a light coloured Colourbond because it would absorb less heat during the day than galvanised or zincalume. In the end our local council requested that we use galvanised because we are in a Heritage Conservation Area. It was tempting for us to argue that our proposed Greeny Flat was anything but a ‘heritage’ design but you have to choose your battles so we agreed to use galvanised cladding. In the end we’re glad we did because we love the overall look and feel of the Greeny Flat and the galvanised steel is a big part of that. More importantly we love the fact that we will never have to paint (or repaint) the outside of the building.
  4. Affordability – galvanised iron (actually steel) is a common and affordable material that has the advantage of going up in large sheets which makes the process of cladding the exterior quite quick, easy and inexpensive. There are some tricky details about windows and doors that have to be carefully considered and executed to prevent leaks but, in general it is an easy material to work with and once it’s up it’s done, no painting or pointing or bagging or other processes need to be completed.
  5. Recyclability – if the Greeny Flat ever has to be taken down it has been built in such a way that almost the whole thing can be taken apart with a screw driver. Metal cladding has the advantage of being very easy to unscrew and take down if that ever proves to be necessary.

Why Plywood?

Oct 29, 2014: Living room looking north-west

Plywood lining on the interior walls give a real feeling of warmth and comfort to the Greeny Flat.

As with the galvanised iron cladding on the outside, we chose to use plywood lining on the inside because it helps us to meet the following Goals:

  1. Recyclability – one of Mum’s design criteria was that she wanted the Greeny Flat to be able to be taken apart at the end of its useful life (hopefully centuries from now) so that all of the materials can be reused or repurposed into something else. It can be argued that gyprock can be recycled by tearing it off, grinding it up, and remaking it into another product, however it cannot be simply taken down and reused somewhere else. So we chose plywood for the interior wall lining because it can be unscrewed from the walls and reused in a thousand possible ways.
  2. Sustainability – the particular plywood we chose to use is called Ecoply (made by Carter Holt Harvey). Ecoply is made in Australia/NZ (as opposed to a lot of plywood sold here that is imported all the way from Chile) from sustainably harvested plantation forests. Using wood products has the advantages of not promoting mining as well as sequestering carbon which is locked away in the fibres of the wood.
  3. Health – Ecoply also uses no urea formaldehyde glue so have very low levels of formaldehyde emissions and a very durable structure. We finished the interior walls with a clear coat product called ‘Polyclear’ (made by EcoColour in Byron Bay) which has zero VOC emissions and is certified Carbon Neutral. It is the same product that we used to seal the concrete floor which was handy because, when we sealed the walls, we didn’t have to worry about covering the floor, we simply wiped off any drips which became part of the floor seal.
  4. Low-maintenance – our plywood walls won’t have to be repainted (although we might choose to apply further coats of clear sealer if necessary in the future) and they are very durable which means that it is easy to attach things to the walls, and any screw holes, etc, can easily be filled with a little putty.
  5. Comfort – having lived in the Greeny Flat for almost a year now I can tell you that I have come to love the feeling of warmth and comfort that the plywood walls impart to the interior. There’s a softness and friendliness to the plywood which is very appealing and, especially in winter time when the sun comes pouring in, the warmth of the plywood makes us feel cozy and protected. In short, we love it and I could spend hours gazing at the grain patterns which remind me of aboriginal paintings and sometimes look like people, sometimes like landscapes, and always interesting.

I could go on about the reasons behind the selection of each and every material used in the Greeny Flat (e.g. click here to read about why we chose to use a light Coloubond steel roof) but suffice to say that nothing was chosen simply for how it looks. There were, for us, many more important reasons relating to the energy performance, affordability, maintenance requirements, health, comfort and sustainability of each of the products we have chosen to use. As it turns out, we love both the function and the look of the finished product which we think is a fine advertisement for the concept of Form Follows Function but please remember that, if galvanised iron and plywood are not for you, you can still apply the principles that make the Greeny Flat work to a house that looks very different. An excellent example of this is Glenn and Lee Robinson’s house in Bundanoon which was designed to not only be net-zero energy and affordable, but also to look and feel as much like an ‘ordinary’ house as possible.


Glenn Robinson's Granny Flat nearing completion with his house in the background

Glenn Robinson’s Granny Flat nearing completion with his house in the background

2 comments to Mar 8, 2015: Form Follows Function

  • Geoff


    A very interesting project. One of my thoughts for external cladding was Colourbond but I have agonised over the things you mention, “There are some tricky details about windows and doors that have to be carefully considered and executed to prevent leaks …” as well as the external corners.

    Can you explain these in detail or is part of your consultancy?

    • admin

      Hi Geoff, I tried to send you an email directly but it wouldn’t go through. Please contact me via our contact page if you would like more information. Thanks, Andy

Leave a Reply

You can use these HTML tags

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>