Building our Home on Lot103

Design
I started the concept and designs for a house some time ago (refer Lot 102) with an understanding the design will be a combination of compromises in relation to position, the view, energy efficiency, usability and costs. The house is a traditional design for the Australian landscape, making the most of the vistas the location has to offer as well as trying to protect the house and occupants from the great range of weather conditions the location presents.

With that in mind I started with some basic ideas to work from:

  • The house location and orientation to take benefit of the views (faces NNW)
  • Position of the house set back into the hill to provide protection from the prevailing SW-Sth winds
  • Use of veranda to protect the house from the sun and offer outside living space
  • Outside living areas to encourage outside use all year round
  • Maximise personal short and long term ‘liveability’ in the house
  • Internals and externals of the house are designed to allow accessibility and usability for persons of varying age and physical mobility including the use of wheelchairs
  • House will aim for high energy efficiency and overall comfort for occupants
  • No public utilities connected to the house. The house will be self-sufficient for power, water and sewerage.

Orientation and Location
The orientation of the house (NNW) is for the view facing the ocean and rolling hills, which fortunately is basically along the contour of the hill. Our prevailing winds are from the SW-Sth, particularly through the Anacotilla Gorge. These winds can provide both a cooling breeze but also consistent strong winds from September to March.
For this reason, the site has been excavated by about 2m with the house set back 1.5m from the excavation. On top of the excavation is a batter that will direct water away from the house site and also form a ‘ramp’ to direct the air over the house. To assist the deflection of the wind the rear roof of the house is at a lower slope, 12.5 degrees and the front the traditional 21.5 degrees.

Building Materials
After a lot of discussions and thought we have gone with the relative traditional concrete slab and light weight timber frame, fibro cement board for cladding and metal roof.
The front of the house is Hebel block and the other three sides Hardie fibro cement cladding. The roof is ‘Heritage Galv’ which gets the dull blue tinge over time rather than staying bright and reflective like Zincalume.

If the HempBlock industry was more advanced and readily available, I would have considered using it instead of Hebel and possibly for the entire cladding. I think it is certainly a material that should become a ‘standard’ acceptable building material for industry.

Shading
We are on a section of a high hill, open and exposed, a previously cleared area for grazing. We have been planting ‘Paddock trees’ since we bought the property but around the house there are no large trees for at least 30m. This is primarily for fire safety.
The house relies on a veranda along the northern frontage to shield the walls and windows from the summer sun. The western wall and entrance to the Annexe has a 4.3m wide carport to protect the wall, windows and door.
The NE wall was to have the shed 1.2m from the house to provide shade, however due to fire safety regulations and our close proximity to the neighbour’s boundary we have had to move the shed 6m away from the house. We will have to rely on good insulation of the entire wall and ceiling space.

Heating / Cooling
We are installing efficient combustion heaters that draw cold air directly from outside into the fire box. This assists in more efficient burning and also does not result in air being pulled into the living area to service the combustion heater.
We are also installing an Air shifter which has an inlet above the combustion heater and delivers warm air into the two bedrooms and study. Because this entire area is a relatively sealed unit air circulates back into the living room.
For solar gain and creation of an outside ‘winter warmer’, clear ‘cafe’ blinds enclose the north area of the veranda and decking. This allows for the winter sun to warm the area and cuts out the cold breeze. Doors and windows can then be opened to other rooms of the house to allow for the warmed air to circulate through.

I debated as to whether to have an airconditioner in either section of the house. I decided to have a Daiken A/C installed in the Annexe for people visiting who may not be as used to ‘driving’ the house for comfort. Surprisingly I used it quite a bit when we first moved in as our combustion heaters could not be initially installed. With the solar system creating plenty of power there seemed no reason not to run the A/C to help the overall comfort in the house.

The house orientation allows parts of the house to be exposed to the western summer sun. To counter this, outside blinds are attached to the posts of the veranda which will reduce the impact of the summer western setting sun. The veranda over the northern windows allows the winter sun to touch the glass which is intended to increase the thermal gain during winter. The windows also do not go all the way to the ground so that the summer sun doesn’t touch the glass any earlier than need be. Anyway, your feet don’t need to look out the window!

Accessibility

  • All around the house curtilage is flat
  • Ramps as well as steps to decking and entrance
  • Minimisation of any lips at door entrances
  • Door handles and light switches at 1050mm off floor level
  • Power points 500mm off floor level
  • Windows and winding mechanism 600mm off floor level
  • Hallways 1100mm wide
  • Doors 920mm wide
  • Fully accessible wet bathrooms

Energy Efficiency
Some of the ideas I have incorporated in the design can be somewhat different to many of the modern house designs I have visited, which tend to have broad window banks for the big views and allow access to the outside. This is more the ‘hat up’ concept where I always wear my ‘hat down’ to protect me from the sun. With the ever-increasing longer periods of hot weather, I wanted to use shade to protect the house during these times. I feel in our climate it is easier to get and keep a house warm during the cold periods than it is to keep the house and oneself cool during the prolonged heat.

The veranda all along the front protects the windows and walls from the summer sun but allows for the lower winter sun to get into the rooms. The outside blinds block a large portion of the summer western sun. Having the blinds also helps create a change of temperature in the veranda area which will hopefully create cooling air movement.

The more northern veranda has clear plastic blinds instead of sun blinds. This enables the creation of a small hot house or ‘sun room’ for sunny winter days. This area leads into the main living space so a door can be open to allow the warm air to move through into the house. I had something similar in our previous house at Glengowrie and it worked very well enabling us to sit out in the area on some very coolish days and provide extra warmth to a cold 1940’s brick house.

In conjunction with the veranda, having the living area protrude from the rest of the house creates outside leisure areas no matter which way the sun, and more importantly the wind is coming from.

All the windows are double glazed and to increase the overall energy efficiency the frames are made of western red cedar with an outside skin of aluminium to reduce weathering and maintenance.

Now to see how it all works out!

Updated 07 Dec 2021