House Design Details

Once we had decided on a mudbrick house, the next stage was to sort out the nitty gritty of design. We drew up plans ourselves, taking care to integrate as many of our criteria as possible. The whole process was a matter of compromise and adjustment and aimed at reaching a final result which would best meet our needs, taking into account factors such as cost, personal preference and perceived significance, to reach what we considered the best acceptable outcome.

HOUSE LAYOUT
The house is basically rectangular in shape with kitchen, lounge and master bedroom to the north with large windows giving a view over our front yard, dam and down the drive. On the southern side are 2 other bedrooms, family room, laundry, bathroom and toilet. There are cathedral ceilings throughout, except for the utility areas which have a lower ceiling to allow for an attic space above. The kitchen, lounge and family room are open plan, which has proved very useful when we are hosting large groups (we’ve had up to 80 people inside).

SOME PARTICULAR FEATURES
THERMAL MASS
Thermal mass provided by mudbrick walls, concrete slab and earth sheltered eastern wall heats and cools slowly, acting to moderate the internal temperature and making the home comfortable to live in all year round. The wood heater is only necessary on the coldest of days, but is used to create a ‘cosy’ atmosphere on other days.

VENTILATION
Cross ventilation is obtained via windows to south and north in our open plan design. Vertical ventilation is created by low air intake from vents and windows and high air exit points in the clerestorey and high vents.

STOVE & HOT WATER SERVICE CUPBOARD
A Stanley Wood Stove is our main cooking appliance, heats all our water and provides some heating to the house. The flue passes through the wall into our HWS cupboard. This reduces the amount of heat coming from the stove in summer and makes the HWS area ideal for use as a drying cupboard. The hot water supply is gravity fed to taps using a 5m head from the header tank located within the ceiling space.

RENEWABLE TIMBER
We’ve endeavoured to use natural materials to minimise chemical release from glues, plastics etc. Radial sawn timber is used extensively internally and externally as a wall cladding above windows and doors. The curves of the boards are perfect match for the flowing lines of the mudbrick. Radial sawn timber is a renewable resource, aesthetic and the milling process uses the whole log with little waste (unlike square cut boards).
Cypress macrocarpa is used for the frame. This is a plantation grown timber which is easy to work with, comparatively light, and contains oils that give it some resistance to insect attack.

EXTERNAL EAVES
These have been constructed to exclude summer sun but allow deep penetration into the house by the lower winter sun. They also protect the mudbrick walls from excessive rain.

STORAGE AREAS
Large built-in-robes provide storage space in each bedroom, a walk in pantry will have extensive specialised shelving and storage areas (for storing produce, home-made products etc.) and the roof space above wet areas has been built into an attic. We plan to build a cool cupboard in the pantry to negate the need for larger refrigerator.

GREY AND BLACK WATER WORM PROCESSING SYSTEM
The “A&A Wormfarm Waste System" processes our “grey and black” water. The water and solids flow into a below ground tank by gravity. A filter in the base holds back the solids which are broken down by aerobic microbes and worm activity. Liquids containing worm castings and minute particles of solids are pumped to absorption trenches. In the future, the liquids will be filtered through reed beds. The captured nutrients will be used to grow biomass as an additional source of composting material and the filtered water will irrigate fruit and nut trees.

IS THE DESIGN EFFECTIVE?
After chatting to a qualified energy rater, we believe that our design would not reach the 5 star energy rating that has been in use for the past couple of years. If this is the case, it is proof that the current computer program used to rate houses is unsatisfactory as its calculations rely too much on insulation qualities and do not consider the full benefits of thermal mass.

The thermal mass in the house maintains comfortable temperatures year round. In winter, it rarely gets below 16⁰C, even when there are frosts outside (the Yarra Valley is known for heavy frosts). We generally start using the wood heater occasionally in May. It gets more use from June to late August (usually just in the evenings) and we only use it in spring if there happens to be an extra cold snap.

In summer, the temperature rarely gets above 30⁰C, and this should be improved once we install a vine covered pergola along the northern wall. Most of the time house temperatures hover around 20º. In terms of function and pleasant living environment the house performs extremely well. Every room is well lit and “airy” and the aesthetic qualities of the building materials are pleasant to the eye. All living areas have good outlook over surrounding gardens and bush allowing us to enjoy the natural attributes of our environment.

A Mudbrick Adventure

We promised to do this post about our house design way back in October last year. (Recently Geoff from Flood Street Farmlet - http://floodstreetfarmlet.blogspot.com/ reminded us about this.) It's a convoluted tale so we will start at the beginning and spend the next few posts filling in details.

We spent several years pondering our house design and considered a wide range of materials and housing styles, ranging from the traditional Australian homestead with verandas all round, through to concrete earth-covered domes. To help us clarify our ideas, we spent about 12 months going on every alternative house tour we could find. This was a great way to explore possibilities. During this period we drew up the following criteria that we wanted our house to meet.

· Maximise our involvement by being owner builders to save costs and to maintain “ownership” of the process
· East-west alignment with large north facing windows to maximise solar gain
· Smaller windows on South, west and east to minimise heat loss
· Minimise fire risk by giving the house a low profile and by using low risk materials
· Eaves to exclude summer sun but allow winter sun to warm house and protect mudbricks from weather.
· Utilise at least some earth covered wall construction (a carryover from our earlier thoughts of building an earth sheltered house)
· Use thermal mass to maintain constant pleasant temperature (20 –25 degrees) and minimise energy use.
· Utilise natural ventilation and cooling pipes (stack and cross ventilation)
· Maximise natural lighting to all rooms avoiding need for lights during daylight hours
· Wet areas to be in close proximity to HWS to minimise hot water pipe distances
· Incorporate a window outlook that provides views of our bush environment
· Accommodate wheelchair access to most of house
· Plan to include provision for large concrete water tank, wood stove and wood heater
· Access between garage, pantry and rest of house
· Cathedral ceilings and exposed beams
· House to have appearance of being part of the environment- not alien to it
· Rooms to be reasonably spacious and Incorporate plenty of storage space
· Use plantation timber (not old growth forests)
· Minimise “wasted” space eg. halls
· Use materials with a low “embodied energy component”
· Adequate insulation using natural non toxic materials
· Use physical termite barriers- no poisons
· House plan to incorporate 3 bedrooms, a study/office/spare room, lounge, family room, kitchen, walk-in pantry, bathroom, toilet, laundry and garage/workshop.
· Deciduous vine covered pergola along northern wall for shade in summer but light in winter

OUR SOLUTION
Our solution was a mudbrick house (external and internal mudbrick walls), built on a slab with one earth sheltered wall (built with “normal” fired bricks and back filled with soil). The house and garage area is around 25 squares. A clerestory is used to bring light into the back of the house. We are very happy with the design we came up with, which meets 99% of our initial criteria.

WHY MUDBRICK?
We decided on mudbrick because:-
· They have low embodied energy
· We were planning to make the mudbricks ourselves. After we had made 80 bricks (out of the 4000 we needed) we decided to buy the rest from Barclay Bricks in Hurstbridge. Back in 1999, puddled clay bricks were only $1.65 each delivered- a very reasonable price we thought.
· They do not require great skill to lay. Slight irregularities in levels add to the “rustic charm”. We use this excuse all the time to explain imperfect lines etc.
· They have good thermal mass (but not good insulation)
· We love the texture of mudbrick wall surfaces
· Laying a few bricks puts the wall up a fair bit because of their large size
· They are fire reistant
· The density of the mudbrick adds an element of sound reduction so that activities in one room have less impact on people in another room
· By building a post and beam frame and later filling in the walls with mudbrick we could put the roof up first and then work on the walls under cover in rain, hail or shine.

In the next post we will get into the nitty gritty of construction and layout.

In the last post I didn't get round to telling why 600 people came to the open day at our place. Sorry about that, but I became distracted by the Tenderbreak Permaculture Farm story and how it came into existance. The story continues with this post, but I promise I will eventually get back to the Open Day.

The two major elements in our permaculture plan were the house design and the construction of a large dam. The previous owners had intended building higher up the slope to maximise their “view” of the surrounding landscape. This would have kept the house away from any suitable site for a dam and made the access driveway very long (and more expensive to maintain). We selected a spot lower down the slope. The dam was positioned 60m to the north of the house site, at the junction of two small gullies which would assist it to fill more rapidly. The dam would offer some protection from wildfire and be a convenient source of water for gardens and fire fighting.

The year we constructed the dam (1995) was unusually wet, causing many delays. Although the site had ideal topography, the subsoils were not ideal. Kevin Jones, our very expert dozer driver had to go quite deep to locate the clay needed to seal the wall. As a consequence, the dam is much deeper than we intended (7m), but since our climate has started getting drier we are very grateful for having the extra water storage capacity.

We played with dozens of different house designs (varying greatly in layout and types of construction). Initially we were intending to build an earth sheltered house using the “Terradome” technique (Interlinked concrete domes). However three main factors changed our mind – the high cost, the need for specialist builders and we were not comfortable with the thought of living inside an almost totally concrete structure.

Eventually we settled on mudbrick construction using the post and beam technique. We drew up plans ourselves, taking care to integrate as many design elements as possible. Over a period of months we gradually changed and refined these so that the final package would best meet our requirements. One day we will do a post on the main features of our house design.

Once we had settled on the concept we sent off our ideas to Rod Sheppard (Earthform Constructions), who we had contracted to assist us with building the frame and roof, and asked him for his comments. After some minor adjustments we asked Rod to draw up the specs, draft the plans, order the timber and list other materials necessary. I took three months off on long service leave (May to July, 1999). Together with Rod, his mate and Heather on weekends; the slab, frame and roof of our house and barn were put up. An advantage of us working on site was that we were able to be involved in making choices as they came up. Building a house is a complex job and very hard for novices to envisage in 3D, from two dimensional plans. As the building took shape we were able to make dozens of modifications and adjustments. Once the frame and roof was up, we basically did the rest ourselves with occasional help from children and friends.

Initially we intended to use timber off the property and our own soil to make mudbricks. Unfortunately these two ideas fell through. Our timber turned out to be unsatisfactory in size and quality, so we chose plantation grown Cypress Macrocarpa for the frame. After making 60 of our own mudbricks, we realized that it would take forever to make the 4000 mudbricks required. So we settled on puddled bricks (made with the help of a tractor) supplied by Barclay Bricks, a local mudbrick company (Hurstbridge).

We sold our previous house in May 2001 which gave us 4 months to get the new house into a liveable state. We moved in, in late August, but still had no external doors, no B.I.R. and no walls on the garage. Since then we have been slowly finishing off the inside of the house and doing what we like to do most of all -developing the food gardens and outside structures. We’ll leave details of building our mudbrick dream house to a later post.