Hydronic Floor Heating

Hydronic floor heating has been put into the slab. There are three return pipes to a manifold which runs off a boiler. The boiler, a linear is a fireplace and although heating the living room and looking nice as a fireplace is primarily heating water for the floor heating. orginally we wanted to have a wetback on a combustion stove, however further investigation lead us to believe that a combustion stove only gets about 15kw of power and floor heating requires around 20. You can still run  it through a combustion stove, but its shelf life would shorten dramatically. A separate boiler was the answer and a fire in winter (although probably not really needed) was the answer. Our flooring cover is the next issue we will have solve as we are avoiding any glues etc that will be emitted as VOC's once the floor heating is activated. We are thinking floor boards which will stop alot of the heat from the floor heating, however the main purpose of the heating is to take the chill of the insulated slab, which it will do quite well, next to find some well seasoned timber.

Bush fire retardant our top priority

Bushfire proofing (well a retardant house anyway). Our location does not gives us the opportunity to flee, too much bush and a winding road through the bush to get out. First the roof, magnesium oxide sheeting under the colourbond roof, no heat transfer. It is incorporated into the eaves and fascia as well. The product we chose was too brittle and hard to use, but had specs for bushfires. The walls, easy as strawbale walls are cobbed so the render is sufficient to deter fire. Shutters on windows and fire retardant (hardwood door). A store room with all of the above surrounding it with air tanks is where we will see out the passing inferno.

A long time between bales

So what has been happening, the house has continued to progress slowly, work committments, unforseen difficulties (like the bridge being washed away, but good things come to those wait. The most important factor to date that has not been published is our attempt to prepare for bushfires. So the next few posts will hopefully shed some light onto how this has influence our final design. I will also put some photos up with our progress to date which includes a slab, frame, roof, shed fit out, the start of vegie garden, chook house, brick chimney and soon to have windows. We (my partner Sonya and I) are still embarking on a great journey and I hope this gives others a buzz to either start such an adventure or just lifts the spirits of those who have already started.

Plans of the house

North is top. Windows might change due to measuring sun angles in winter to maximise thermal mass. All water is located in the SW of the house, to maximise grey water movement. Electricity is also mantained on the back half of the house to limit cable use. Elevation plan to come.

View looking north

Here is a view looking north from where the bales have been stored. This is at about 4pm near enough to winter solstice, so still sun on the main part the house. Bales were stored on site. Most are wheat straw, well strung and fairly tight. Making a straw bale needle at the moment from some scrap I found, will provide a photo later. the shed is now full of straw bales and still wrapped in a tarp. The workshop is at the other end and the rise I am standing on is still getting sun all day which is good for pasture, bee's, orchard etc.

the shed and foundations

Things are finally happening, a slab for the shed and blockwork for the house slab have been completed and shed is roofed and bales out of the weather. The shed will also have a sleep-in workshop (straw-baled) on the northern wall.

The workshop will be strawbale and cob with an external colourbond wall for weather protection, due to the lack of eaves on the existing shed structure. We have acquired a large piece of cast iron to embed in the north-facing internal wall for thermal mass (see picture).

Straw bales got a little wet from a storm this week but only on the outside, can't wait for the walls.
This winter we have had over 500mm so far with alot more on the way.

Also have a concrete tank of 40000 litres with 10000 litres for fire fighting.

Risk of bushfire!

Our number one risk on the property is bushfire. We are on the top of a ridge with Eucalypt forest on either side. The slope is at least 20% in some places and obviously fire prone (blackened trunks evident). So in the design we have aimed at using fire resistant materials and have a sensible design.

1. Fire resistant materials- Straw bale walls. Believe it or not the straw bale wall is one of the most fire resistant materials around. It's ecological foot print is low and it's insulation properties are fantastic. Alot of manual labour is also on the cards but is already looking satisfying. The lack of oxygen and air flow is a key and the cob and render on the outside also add to the fire integrity of the product.

2. New hardie materials, hardiflex or masonite like panels are easy to put up, no spaces between sheeting and fire resistant, will still need to put insulation and framing up.

3. Rokcore roofing (colourbond with poly infill)- A1 fire rating, low cost for structural support and easy to put up. Can take a low pitch design and easily rendered up to easves.

4. No gaps or spaces and limit ember catches.

5. Steel mesh guttering and window shutters.

6. Inbuilt sprinkler system.

For starters this is our main physical defense with 40,000 litre concrete tank and protected fire fighting pump in housing with cooling mechanism.

The last thing to think about is a fire plan which we are developing. Anyway food for thought....