Wood-fired Oven

The EcoLiving project undertook to build this wood-fired oven within the area used by the Violet Town Market as a community asset, and to promote local natural food and local fuel wood from sustainable forestry. The oven was built by a tremendous volunteer effort lead by Neil Garrett, with notable contributions from Bill Wood, Mick MacLaughlin and many others, and co-ordination by Warwick Paton.

Neil Garrett, architect and builder of the oven, celebrating completion, 26th May 2011 photo: Sandy Garrett 

Sandy Garrett and Sue Paton serving pizzas at the May 2011 market, while Neil takes care of the baking. Photo: Paula Ajuria
The weekend before this market Thomas Moritz of Boonderoo Farm bakery lead a workshop on operating the oven, and making pizzas.

Thomas at the workshop. No wonder the oven and pizzas attract a lot of interest at the market - the oven looks good, and the pizzas inside with the fire look so good. They cook and taste as good as they look. Photo: Paula Ajuria
For baking pizzas a fire is kept at the rear of the oven, and the pizzas cook with conducted heat from the base bricks through the pizza tray, radiant heat from the bricks in the vaulted oven ceiling, and convected heat from the air circulating through the oven. The only way into or out of the oven is through that doorway - the old cast iron door and frame was salvaged from the old scotch oven that baked the bread for the village until 1969. This new oven is highly efficient with well insulated thermal mass. It can stay hot and keep baking for a day after firing it overnight with just a barrow load or two of wood. The Violet Town Lions Club have been supplying the wood for the oven.
Workshop participant Paula Ajuria writes... "First time making pizzas in the oven was a success with many participants at the workshop taking turns at shuttling pizzas in and out of the oven on the pizza shovel. 
As a local farmer and baker, Thomas believes in community self-reliance and firmly promotes local and seasonal products for making pizzas. He pointed out that there is no need to offer some of the familiar pizza combinations such as ham and pineapple as we can top our pizzas with a great variety of foods from this area, and as he pointed out, 'we can’t grow pineapples here!'
Neil’s choice of glazed bricks (2nds bricks bought cheap from Euroa Clay Products) was influenced by his recent travels to Spain, Portugal and Morocco.  The oven's bricks are practical as they stay clean and its bright colors integrate harmoniously as a feature in the area next to the children's playground."

Kaye Bradshaw (chair) and Sarah Hamill (co-ordinator) of the Violet Town Community House selling pizzas at the market. Photo: Paula Ajuria
Violet Town Community House has taken on the management of the oven. To book the oven for private functions or to enquire about community group use contact Sarah on 5798 1288 or violettowncommunityhouse[at]gmail.com 


During the workshop Paula learnt from Thomas that many people who are gluten intolerant - an increasingly common condition - can safely eat sour dough bread. Sour dough baking uses a beneficial brew of wild yeasts and bacteria that ferment the flour, and which break down the gluten. This was exciting news for Paula as she is gluten intolerant and had not eaten wheat flour for 10 years. She did some research, made and ate some sour dough bread with no ill effect, and wrote this summary of her research.
"Only a retained heat wood fired oven gives you that unique flavour that can not be reproduced in a normal kitchen oven and only sourdough brings out the taste of bread as it was known originally.  The oldest and most original form of leavened bread originated, like wood fire ovens, in Egypt around 3000 years ago.
Sourdough remained the usual form of leavening down into the European Middle Ages until being replaced by barm from the beer brewing process, and then later purpose-cultured baker's yeast. Some bakers have kept using the sour dough process.


Health benefits of sour dough:
All grains contain phytic acid (an organic acid in which phosphorous is bound) in the outer layer or bran. Untreated phytic acid can combine with calcium, magnesium, copper, iron and especially zinc in the intestinal tract and block their absorption. This is why a diet high in unfermented whole grains may lead to serious mineral deficiencies and bone loss.
Soaking allows enzymes, lactobacilli and other helpful organisms to break down and neutralise phytic acid. As little as seven hours of soaking in warm acidulated water (sour dough leaven) will neutralise a large portion of phytic acid in grains.
Soaking in warm water also neutralises enzyme inhibitors, present in all seeds, and encourages the production of numerous beneficial enzymes. The action of these enzymes also increases the amount of many vitamins, especially B vitamins.
And if you are gluten intolerant:
During the process of soaking and fermenting, gluten and other difficult-to-digest proteins are partially broken down into simpler components that are more readily available for absorption. If the fermentation process continues for long enough and the requisite bacteria are present then most if not all of the gluten may be broken down. This would explain why some gluten-intolerant people can digest sourdough bread without any symptoms of gluten allergy." Paula Ajuria
Reference: Nourishing Traditions by Sally Fallon

The completed oven. photo: Sandy Garrett

Deflect Unwanted Heat

Deflect Unwanted Heat
The biggest way that the building deflects unwanted heat is by the solid shade provided by the roof. We have greatly enhanced this deflection of heat by painting the roof with heat reflective paint, and by replacing the old skylights that were effectively a hole in the roof, with the roof windows that have solid canopies and appropriate eaves.
Heat Reflective Paint
Applying heat reflective paint was the single biggest and most cost effective impact we have had on the operation of this building. For approx $14 000 excl. GST, the 1600sq metres of roof over both buildings has been painted. The paint we used, Astec Energy Star white, is said to reflect 89% of heat, and is also very good at releasing heat to the night sky – 89% emissivity. 

Kevin Jacka applying heat reflective paint to the roof of the Meeting Room. It is bright up there!

Afternoon on the roof of the Community Complex. The sun is behind the camera, so the light and heat is being reflected away. This roof is mostly flat or low angle, so the glare mainly only effects people walking on the roof, or passing helicopters. For a steeper roof a darker colour of heat reflective paint could be used, to produce less glare. Note also reflective tinting on high windows of Hall, visible to left of picture. It is 3pm on 23rd February, and the sun is just about to start shining onto (before tinting, into) these high windows.


After applying this paint we received many comments from the regular users of the building that it is now appreciably cooler in summer. The cost to supply and apply this paint worked out to about $9.50 /sq metre, including GST. It is expensive as a paint, but can be relatively cheap as a cooling strategy for difficult to insulate roofs.


Most of my direct experience with this paint is with this building, with its very poorly insulated ceiling. However Kevin Jacka, the painter, then went home and painted the metal roof of his own weatherboard house with this paint. His ceiling had about R2.5 insulation. On the summer's day that he put just the primer/undercoat on, his wife came home and said “The house is cooler.” Kevin put the top coat on, and is pleased with the effect. The paint may well be worthwhile applying on roofs where the ceiling is insulated.


However it is a plastic paint and I would like to know more about how it degrades in sunlight before using it on roofs that supply drinking water. I have asked the supplier for more information about this, which they have not as yet provided.


Heat reflective paint is also available for tile roofs, and for walls. Tony Nicholas has used it to very good effect on a west facing wall of his brick house in Hurt St Violet Town. [At Tony's initiative the EcoLiving Project is also encouraging VicTrack to put this paint on the metal shelters on railway platforms.... we'll see how we go with that. I am sure it would be very worthwhile, if they decide to do it.]


Replace skylights with roof windows
see also Use Energy from the Sun  The old skylights leaked air, occasionally water until patched up, and definitely leaked heat and cold.

This old skylight above the kitchen needed to be replaced, and was a hole in the roof letting in heat, cold, and the sun's rays in summer.

Andrew Otto installing the supper room roof window at midday on December 21, summer solstice. Note the shadow line from the eave extends right to the front of the flashing, well away from allowing sun to enter the room below.


Install apropriate eaves on north windows
There were a number of north facing windows around these buildings that, while being valuable in winter, needed an eave to keep out summer sun.

New canopy/eave installed over north facing window in library courtyard. Shown in May 2010, with warm light entering the library.


Window tinting
Window tinting film can be applied to the inside of existing windows to deflect unwanted heat. This is a compromise solution, because with the deflection of heat comes reduced light passing into the building. A basic purpose of windows is to let in light. However some windows in these buildings, particularly in this case west and south west facing windows, were problematic for letting in summer sun, and we accepted the compromise of reduced light.

Paul Natalizio applying film to a west facing window in the Supper Room. Reduced light from these windows is now more than compensated for by light from the new roof windows. In summer the blinds were kept drawn anyway, because of the sun's heat, so the windows are now more functional than they were.

We used Optitune 15% film, which lets 15% of light in, and rejects 84% of heat. Paul of GV Window Tinting gives a lifetime guarantee on his application of this film for private homes, and a 10 year guarantee for commercial installations. Why the difference? Because the tinted windows must only be cleaned with mild cleaners, and he has found that cleaners of commercial buildings tend to use stronger cleaning products that reduce the life of the film. Sheryl Taylor, the VT Hall Committee, and Strathbogie Shire have all taken note of this. Sheryl only uses mild cleaners at the Hall, anyway.

Mike Larkin preparing wiring for the big fan in the Hall. Note reduced light coming in from the tinted SSW facing windows to right of picture, compared with the NNE facing windows at left. Before the windows at right were tinted, the sun would start shining right into the Hall in the late afternoon, heating it up just before a summer's evening event.

Heat Reflective Blind
Unlike permanently applied tint film, a heat reflective blind can be raised and lowered, giving control over when the effect. It can be raised to allow more indirect light into the room when the sun is not shining in, or to allow winter sunshine in to warm the room. It is more expensive than tinting, but preserves more of the use value of the window.

Sean, Indigo and Steven demonstrate the open-able heat reflective blind installed on a west facing window at Violet Town Community House. This does require someone to think about how the blind works, and actually open it when appropriate – in winter for example to allow the afternoon sun to shine in.

Landscaping for shade
Of course buildings, or badly sited windows, can be also be shaded with vegetation, which is a less energy expensive, and financially cheaper, strategy than high tech window tinting. This works well if well managed. Best if a gardener lives in the building, thinks about how it works, and manages that vegetation to best effect. For this public building we mostly had to accept that the landscape plantings will remain pretty much as they are.

Cutting back the tops of the existing photinia bushes to let winter sun into the Main Hall is one exception. See Use Energy from the Sun. Creating shade for the entry courtyard is another exception. If we can create a leafy shaded space over that courtyard we will deflect heat, create active cooling through transpiration of moisture through the leaves, and create a cool air space from which air can be drawn into the building.

Pergola frame over south facing courtyard garden is to carry four grape vines, which will be guided up the chains hanging from each corner. Shade from the vines will further cool this space. Pergola constructed by Comspread Engineering. Courtyard garden about to be re-landscaped by Graham Jones and Yuta.


Constructing this pergola to carry grape vines and shade this courtyard in summer is an excellent cooling / energy efficiency strategy, but the decision to construct the pergola out of steel is very questionable. I took advice that it should be constructed  with galvanised steel for a longer life than timber. On reflection I would prefer to have used very dense Australian hardwood such as Sugar Gum, Ironbark or local Box eucalypt, which in my own and others experience is very durable for outdoor construction.

For any sustainable / energy efficiency project, the embodied energy in the material needs to be taken into account. For the steel, think about the energy cost of digging up the iron ore in Western Australia, digging up the coal in NSW or Queensland, freighting both to port, shipping them to China, freighting these to the steel mill, burning lots of coal to make the steel, then freighting / shipping / freighting the steel back to Violet Town! Compare this with the small energy cost of cutting up a log from within 100 kms, possibly much less, to get durable hardwood timber.

David Arnold