Using permaculture ethics & design principles to transform an old energy guzzling bungalow into a showcase of sustainable design. It's about energy cycling, building community, self-reliance,creatively using & reusing materials... all without spending heaps of money.

Saturday, October 24, 2009

Getting floored

Principle 2: Catch and store energy
Principle 3: Obtain a yeild

Baltic pine floorboards recovered from the original building were put aside for use in the two bedrooms. Baltic pine is quite soft, and damages easily, making it inappropriate for high traffic areas. I figured that I would have enough boards for both bedrooms as the boards covered two rooms about the same size and the original kitchen (now a study / 3rd bedroom). It turned out that it was a very close call with all useable boards used.

For the remainding rooms in the building we decided on recycled hardwood floorboards. The timber is a lot more durable, easier to work with and fairly cheap (at around $3.10 per lineal metre when bought in bulk). Being narrower though, 105mm instread of 150mm, they can take quite a while to install. Each room took about 16-20 hours to install (including insulation).

I planned to have insulation under the floor because of heat losses in winter of 10-20%, as well as heat gains in summer. The options that I considered for underfloor insulation were:
  • sawdust (using masonite under the joists to hold it in place) - this technique was used in old homes, but only generally in ceilings. Problems with it include a fire risk (it can spontaneously combust), and if it gets wet it can attract insects. Also installing masonite would be difficult.
  • raw wool straight from the sheep (using masonite under the joists) - being sheep country, cheap daggy wool is probably available locally. Benefits include: it is grown locally, is biodegradable, does not irritate and naturally flame retardant. Unfortunately it needs to be sprayed thoroughly with borax (which has a low toxicity) to avoid it becoming a breeding ground for moths, washed as it exudes grease and sheep sweat which can make your house very smelly and it needs to be enclosed in a cavity. Another thing to consider is that the sheep may have been treated with chemicals (dipping).
  • pure wool batts (using masonite under the joists to hold it in place) - a good alternative, but are expensive. Local R2 batts are $A13.50 per m2 and not available until for six months - because of the Home Insulation Program that the federal government is offering.
  • rockwool - 'optimo' a new underfloor product which wasn't available at the time. I also have concerns about the amount of energy used to produce it (it's molten rock spun like candy floss), and the safety concerns as it can be inhaled (similar to fibreglass and asbestos).
  • 'foilboard' - a ridgid product that could be difficult to install as joists are second-hand and not all evenly spaced.
  • polyester batts (using masonite under the joists to hold it in place). Considered birdwire, but thought that it would become a breeding ground and nesting material for rats / mice. Lcally available, low toxicity, long life (50 years plus), low off-gassing and cheaper than wool batts at $A5.60 m2 for R2. It's a non-renewable resource (made as a by-product from crude oil processing), but highly recycleable.
  • cellulose insulation (using masonite under the joists to hold it in place) - lowest embodied energy of the mainstream optioons, uses the most recycled content, often needs experienced installers to get the material fitted correctly. Not aware of any local installers.
  • permifloor 500 - a double sided reflective foil with a thin layer of foam in between with small holes throughout allowing it to breathe. Unlikely that rodents would breed if they got in as there is no nesting material. Become less effective if dust accumulates.
  • Rice Hulls - while researching this blog I found some interesting information about using rice hulls as insulation (download pdf here). It appears to be very cheap, with some great qualities (for more info see "The Rice Hull House" article). It's insect resistant and virtually fire proof (see report). It has an R3 value per 25mm according to this report.
The idea of creating a base for the insulation to sit on did not appeal. Working on my back under the floor to nail on sheets and having to cut them all to the correct size would be a real pain - which rules out most of the options available. I chose the permifloor because it looked easy to install, was available locally, effective and was recommended to me. While it's probably not recyclable, and probably has high embodied energy, it's very durable and could possibly be reused. There is a need to ensure that all of the underfloor is enclosed, as the accumulation of dust reduces it's effectiveness, as does air gaps.

Bedroom one and two being prepared for floor installation

Permifloor 500 floor insultation installed easily using a staple gun

Using floor clamps to compress boards together before nailing

Hardwood floor boards being transported from Heathcote via the Tooborac Pub & Brewery

Flooring completed of the study using recycled hardwood (foreground) and two bedrooms using baltic pine from the original house.

Tuesday, October 13, 2009

Sourcing energy

Principle 5: Use and value renewable resources and services

Now that I've got the frame up I can get electricity hooked up to the house, I opted for an underground connection. Once the physical connection has been made by the electrician I needed to choose which company I wanted as my energy provider. This gets really confusing as there are heaps of retailers with heaps of options. There are websites that can help you decide which retailers offer the best deals for your situation - just do a search for 'compare energy suppliers'. The energy retailer is not the energy supplier though, the retailer is the 'middle man'. The energy supplier is responsible for the 'on the ground' work.

Regardless of what company you choose you will need to decide whether you want a 'flat rate' or 'peak rates'. In my case a flat rate is $90 to connect, with a lower service charge of $196 p.a and a flat rate of 17.325 c/kWh. The peak rate is $290 to connect, with a service charge of $220 p.a. and a peak rate (7am-11pm M-F) of 18.821 c/kWh and an off-peak rate of 10.659c/kWh. It makes sense to get the dual meter (with off-peak rates) if you use a lot of power at night - which is good for poorly designed homes that need electric heaters on at night or have electric hot water systems that take advantage of the off-peak rates. By choosing 100% GreenPower from my retailer I will be charged an extra premium of 5.5c p/kWh, which will ensure that energy used in my home will be generated by renewable sources.

I've decided to go with the standard meter (flat rate) because I will have a slow combustion wood stove for heating (that will only be needed during the few coldest months of the year) that also will boost the solar hot water system (at the same time that the boosting is most needed). As the hot water system that I am looking at has an electric element built into it I am considering using this as a tertiary back-up with the element on a manual timer and an on/off switch, so that it doesn't run when it is not needed. I am also considering an instantaneous gas booster to heat water instead of electricity, but I don't think that it will be used enough to justify the cost - in fact it may not be used at all (an extra $1500 - $2000 by the time it's installed).

Another reason why I have chosen the standard meter is because I am considering getting a solar power system that uses grid storage. This requires a different type of meter (import/export) that you can only get when you have the system installed, so it makes sense not to spend too much at this stage. A feed-in tariff at a premium of 60 c/kWh (in Victoria) will be deducted from my electricity bill for excess energy generated by the system, but I am looking at installing a small system (1 to 1.5kW) that is unikely to generate much more electricity that is needed. While a feed-in tariff is a great idea, the current version of it is flawed.

Cooking with gas is much more enjoyable than cooking with electricity, and will compliment the wood stove - which isn't fun to cook on in summer. I found out that it is cheaper for me to get bottled gas rather than mains gas (which runs right by the property). It seems crazy to use bottled over mains gas, but I only want to run a gas stove and oven, which I've been told would use about one 45kg bottle per year (probably less). The bottle rental charge is $25 per year, and a refill costs $90 - that's $115 per year. It's free to get mains gas connected (depending on a site assessment), but the supply charges for a gas connection are $162 per year plus the gas charge of 1.41c/mJ. There's about 52mJ to the kg, so 45kg of gas would cost about $33 - that's $195 per year. A $162 connection fee to access $33 of gas... hmmm. It would make more sense get the mains gas connected if I used a gas boosted hot water system. Another thing to consider with bottled gas is what to do if there is a fire.

Of course using a wood stove require wood, which is a renewable resource, unlike dirty brown coal (used to generate 85% of Victorias electricity) and gas. Presently there is plenty of firewood on site, since the Red Gum was felled and the old house was deconstructed. In the longer term firewood can be sourced from sustainable sources in the local area, as it is a rural locality. If you are prepared to do some scavenging around town then there's plenty of clean timber that's being thrown out. It's important the timber is clean and dry before it is used to ensure low emissions and a long life for the stove.

Check out some of the concessions that are available to reduce your energy costs if you are a concession card holder.

Monday, October 12, 2009

Getting the run-off to run-in

Principle 1: Observe and Interact
Principle 11: Use edges and value the marginal

I love watching water flow after big rains. Water flow indicates the topography of the landscape, showing high and low points of a site that may not be obvious during the dry.

The laneway to the east of the housesite collects a lot of water from backyard sheds and driveways which runs down wheel rutts into the stormwater drain. The water pools before it overflows into the drain, which has resulted in a muddy mess where cars can get stuck. I've been thinking about making use of the laneway entrance for the driveway to the carport, in which case I need to address the waterlogging issue.

Water run-off from laneway after heavy rain

I've also been thinking about how I can make use of water as a resource... when I stumbled across a book by Brad Lancaster called "Rainwater Harvesting for Drylands and Beyond" which inspired me to act. Below are a couple of illustrations with captions from his website

The wasteful path to scarcity. The site rapidly dehydrates itself by erosively draining rainwater and runoff away to flood downslope areas and contaminate surface water with sediment. Greywater is lost to the sewer. Costly municipal or well water is pumped in to replace the free water that was drained away. Leaf drop/mulch is also drained away further depleting fertility and water-holding capacity. This leads to a depletion of resources and feeling scared in the city due to the resulting scarcity.

The stewardship path to abundance. This site passively hydrates itself by harvesting and infiltrating rainwater, runoff, and greywater on site, reducing downslope flooding and overall water consumption and contamination. The need to pump in water is greatly reduced or eliminated. Leaf drop/mulch is also harvested and cycled back into the soil and plants further increasing fertility and water-holding capacity. This leads to an enhancement of resources and a bun dance of celebration due to the resulting abundance.

I had planned to get the 'Kanga' back to dig a trench for the underground power cable and figured that I should do some landscaping at the same time. The idea was to use the excess sub-soil that was left over from previous earthworks to create an earth-berm which would hold excess run-off and allow it to absorb into the soil.
A small channel will pick up water from the laneway and feed it into the soak.

Top soil was put aside (see top right of picture below) and used to cover the sub soil, making it easier for plants to grow in the future. Red Gum mulch (centre of picture) will be used to cover the earth berm near the right of the picture, but kept away from the edge of the house as it could attract termites. The berm to the left of the picture will become a raised path and prevent water from running under the house. When the area fills with water it will overflow out the old driveway and into the stormwater drain.

It is hoped that the area will act like a mini wetland, attracting small native animals like lizards, forgs and birds which will help control insects and create a beautiful living space.

Using 'Kanga' to create an earth berm which will capture run-off from laneway and watertank overflow to form a mini wetland

Using a laser level to ensure that earth berm is level and that overflow runs towards stormwater drain, not under the house (you don't need to use a laser level - I just had access to one)

Captured run-off after heavy rain, water soaking into the ground after a few days
Filtration basin in front yard leveled out and covered with redgum mulch. Water runs in from bottom right of image and overflows at bottom left of image. Note: it is recommended to have the basin 3m from the foundations which I have not done - I may need to modify the design.

Thursday, October 1, 2009

Termite resistant design

Principle 6: Produce no waste

Termites cause more damage to Australian houses than fire, floods and storms combined - damage that is not covered by household insurance.

Termite nest found on house site in trunk of Red Gum after it was felled. Termites can travel 50 - 80m to feed from a nest.

How termites can move from a nest to a house

Termite attack in kitchen of original house. The original house had wooden stumps set into the ground with no ant caps and a low clearance where water pooled after heavy rain - a recipe for termite attack.

Generally speaking termites like dark, moist environments and love to eat wood. If you keep timber away from the ground around your house, ensure that water runs away from the house, and keep dark spaces well ventilated then you are off to a good start. It's very important to ensure that you have an inpection area that surrounds any item that is in contact with your home. Inspections should be made every 6-12 months in termite affected areas.

Here are ways that you can reduce the chance of termites causing major damage to your home: (from building commission website)
  • Check your property and building regularly for termite activity to reduce the risk of damage
  • Plumbing leaks, drainage problems and roof leaks should be addressed promptly, as termites are attracted by damp conditions
  • Garden beds should not be built up against walls, as this allows termites an undetectable entry point to the building
  • Do not block or cover sub-floor ventilation with garden beds or paving
  • Do not stack materials against walls, as this can allow termites to enter without early detection
  • Sub floor areas should be well ventilated and vents should not be obstructed
  • Storage of cellulose products in the sub floor space should be avoided
  • Use termite resistant timber for works around the property, including retaining walls
  • Use metal stirrups for verandah and gateposts
  • Clean and check timber decks regularly
  • Do not build rainwater tanks up against walls, as this may allow termites an undetectable entry point to the building
The CSRIO has also produced a fact sheet called Termite or 'white ant' treatment and prevention which is worth a read.

A termite built mud tube on a bush pole that was set directly into the ground.

Fragile termites exposed from under mud tube

Termite resistant design is something that we have considered right from the start, but I think that it would have been a wise move to consult a termite specialist early on in the process. Most physical termite barriers need to be installed early in the construction phase. By consulting a termite specialist you can be made aware of the current options and techniques used to manage termites, according to your specific needs. Specialists should also be up to date with the current regulations, to ensure that you do what is required to get the 'Termite Treatment Certificate', which is needed in order to get the 'Certificate of Occupancy'.

The building permit notes that the Abdallah House is in an 'area designated as subject to termite infestation' and that protection is required from termites in accordance with Australian Standard 3660.1. Apparently, I must employ both physical and chemical techniques in order to comply with the standards - but in order to find out what the standards are I need to spend $142 to get an electronic copy of the book.

Concrete is an effective barrier to termites, unless it cracks. Cracking in a concrete slab is more likely to happen if it was not prepared properly, which is very common in the age of quick construction - hence underslab termite treatments are often used. Because we compacted the sand fill, vibrated the wet concrete and poured it during the coolest time of the year, we are less likely for the concrete slab to crack - and so fulfill the criterea for a physical barrier according to the Australian standards. If we didn't do that we may have had to drill holes throughout the slab and inject termite treatment - an expensive and messy job, with an unsightly finish. Areas have been left uncovered above the slab insulation for termite inspection.

Concrete stumps with ant caps are another deterrant that we employed. There are chemically treated ant caps that could have been used, had I know before we did the job. Good clearance (400mm) between the ground level and bearers and joists ensure that there is good access for regular inspections as well as allowing the possibility for good ventilation.

Around all areas with ground contact to the house I have dug out a small trench which we are looking at filling with sand mixed with a chemical that will adhere to termites that are in contact with it and infect a termite nest within 15-20m. The chemical is water based and does not smell - and is more expensive than standard treatment which is rather toxic and repels termites rather than infect their nest. Chemical treatments like this need to be replaced every 5 years or so.

Termite treated timber has been used for all framing, this is guaranteed for 25 years. When treated timber is cut and is left exposed it needs to be retreated with an areosol spray.

I was recently told that termite live in acidic conditions, which is why they are so prevalent in Australia. Apparently lime is a good deterant as it is alkaline, which could be a good alternative to harsh chemicals.

100mm wide x 75mm deep trench dug around concrete stumps to be filled with termite treated sand. Ant caps on top of stumps deter movement up into the house structure.

Termite inspection area above slab insulation. Termite treated timber used in construction.

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