06 February 2010

Building the eco friendly way - On the way to completion

Above is a near complete progress shot of the front of the house. Painting is complete and the external paving and retaining works are underway. Note the photovoltaic panels just poking above the higher roof.

The house has many sustainable features and the rear wall of the house is the 'engine room' for most of them. In the image above from left to right:
  • To the very left is the 23,000 litre rainwater storage tank. This tank provides all of the potable water needs for the house, ie; drinking, cooking and showering water.
  • The vertical white rectangular box is the gas heating unit for the underfloor hydronic heating system
  • Next is the white vertical 'tube' which is the first flush system for the rainwater tank. A first flush system diverts the first flush of each rainfall away from the rainwater storage tank preventing any dust, silt or contaminants from making it into the houses water supply
  • The next three matching 'boxes' are the greywater recycling system. This system takes greywater from showers, basins and the washing machine and cleans and recycles it for re-use within the house for flushing toilets and back to the washing machine. It is also used for watering gardens and lawns
  • The next two items are part of the solar hot water system. On the ground is the hot water storage tank and on the wall is the gas heating booster which is used when there is insufficient sun to provide the solar heating for the hot water.
  • And finally on the ground is the start of the installation of the pumping system for sending the rainwater through out the house.

The front entry of the house has been designed to act as a two storey breezeway, circulating air throughout the house. At the top of the image you can see the louvre windows that form the main functional component of the breezeway, providing very fine control over airflow and direction. By selecting the right louvres to open it is possible to facilitate direct cross ventilation, diverted cross ventilation to another part of the house, and on still draw by opening all of the louvres, stack effect can be utilised by allowing hot air to rise and draw through cooler air from below.

Carpets can be a significant issue when it comes to green building. Many carpets and underlays have high VOC emissions, are made from non-renewables and are non-renewable at the end of their life, so it is important to select with care. The carpet we will be using is a low VOC 100% wool carpet which is laid on a underlay that is made from recycled clothing, shredded to from a soft underlay.
Towards the back of the image, the recycled timber architraves and skirting boards can be seen.

07 December 2009

Building the eco friendly way - External cladding complete and internal fix out

Above is a progress photo of the front/North of the house with all of the external cladding completed.

Keeping the summer solar heat gain out of large north facing windows can be a problem. We love providing lots of natural light into houses but are very conscious of the heat gain issues large areas of glass create. Even with high performance Low E glass, solar heat gain in summer can be a problem.

To manage this, we install retractable external venetian louvre blinds to the windows. When retracted the blinds are hidden in a pelmet box over the windows as you can see in the image above.

The blinds operate through a range of positions from being totally closed and providing full sun shading, to open 90 degrees to allow for increased light but still providing partial shading, right through to totally open as per the image above.

The internal fixout and joinery is well underway, as you can see from the image above the kitchen has been installed.

Achieving an eco-friendly kitchen is about choices of materials, products and appliances.

For the cupboards we have used sustainably forested and harvested Hoop Pine plywood, and for the island bench breakfast bar we have used solid reclaimed Spotted Gum. Wherever possible we prefer to avoid the use of manufactured board products such as MDF or particleboard, many of these products are very high in formaldehyde emissions, as well as contributing to the wood chipping and pulping of native forests.

The dishwasher and kitchen mixer tap are 4 star water efficiency rated and the electrical appliances are all 4 star energy rated. In our opinion 4 star energy and water efficiency is the minimum that anyone should settle for. The cost premium for this level of appliance is so minor compared to the water an energy saving over, say a two star rated appliance.

Heat trapped at the top of a room between the head of the door and the ceiling is a major contributor rooms heating up in summer. Even with good cross ventilation, if there is no way for this trapped heat to escape, then it will stay in the room.

The way we deal with this is by installing a small bank if timber louvres over each door, which can be opened or closed depending on the requirement to heat or cool a room. In the image above, the louvres can be seen over the two bedroom doors. Once the louvres are open, the trapped heat is free to continue on its breeze path and maintain full cross ventilation.

The strange thing about this, is that this sort of installation is a not a new concept. Victorian houses has openable highlight windows over many of their internal doors. What we don't understand is at what point did such a great idea disappear from standard construction?

We have commenced internal painting and are using Natural Paint from Murobond. We feel the name says it all. The paint contains milk, egg white, vinegar and linseed oil to name but a few ingredients which are all natural, bio-degradable and from renewable resources. NO petrochemicals or heavy metals can be seen. Beats me why anyone would use anything else but natural bio paints.

Good for your health and good for the earth.

19 October 2009

Building the eco friendly way - Cladding and internal fix out

Unfortunately when choosing to use a hardwood in their home, most people are not aware of the environmental issues associated with that choice. Although any tree that is cut down for timber can be replaced with another newly planted tree, most Australian hardwoods are slow growing and a lot of the timber that you may get from a timber yard could be from a tree 50 years old. There has been so much logging of old growth forests carried out in Australia over the years that we really are getting to the point where we should think about stopping.

Making the right sustainable choice for hardwood IS hard. As a minimum, if you are obtaining new timber, look for timber that has some from of chain of custody accreditation, such as FSC.

OR do what we do.

We only used reclaimed or recycled timbers.

The image above is of some Red Ironbark stair treads that were salvaged from a warehouse in Sydney.

Below are some recycled Bluegum posts and beams being used for some external pergolas and verandas.

Not only is reclaimed and recycled timber a very sustainable choice, it is also a much better timber. Newly logged timber is high in moisture and therefore very unstable. To reduce the moisture content in the timber, it is force dried in kilns to dry out and reduce the moisture content down to a stable level. The problem with such forced drying is that the timber is still prone to warping, cupping and twisting as it re-adjusts to it's new environment.

With recycled or reclaimed timber, because it is so old, it has dried out naturally and is a very stable timber.

Below is some more recycled Bluegum which has been used as feature wall cladding at the entry to the house.
Below is another progress photo of the front, or North of the house.

Keeping cool in summer is critical to a well designed green building, particularly when looking to avoid air conditioning.

To achieve this, cross ventilation and ventilation control is the key.

We find that louvre windows such as the one above below are the best way to achieve fine control over the amount of ventilation required.

Louvre windows are the only windows that allow you to open a window a full 100% for maximum cross ventilation of to feather that back to a fine opening of only 2% to ensure fresh air supply.

They look good, provide uninterrupted vision because there are no framing members and are very secure.

The old loose and rattly louvres of the 50's are a thing of the past. The louvres currently available seal so well that they are cyclone rated.

23 September 2009

Building the eco friendly way - External cladding and building envelope

As one can see from the image above, things are progressing along nicely. The external Fibre Cement cladding is nearing completion to the first floor, all windows are installed and some internal works have commenced. On the second floor roof a photo voltaic solar array is just visible above the roof sheeting.

The solar array, below, is a grid connected 3 kW system which we believe should look after all of the household power needs, making the house a genuine zero carbon or carbon neutral house.
The panels have perfect due north exposure and are mounted on support frames to bring them up to the optimal solar angle for Sydney's latitude, thus ensuring they generate the most energy possible.

An important but often overlooked aspect of good passive design is ensuring that a house is well insulated. Insulation products are available in various 'R' values. An R value represents the thermal resistance of the particular insulation product. So in theory the higher the R value, the greater the insulating properties.

However achieving a well insulated building envelope is not just a case of using the highest R value you can find. It is possible to have too much insulation. Insulation works on trapping air between the fibres, so good loft is required for the insulation to work properly. If insulation is squashed into a wall of roof to make it fit, then the insulation will not loft and won't perform to its optimum. If you don't get the full insulating value from your insulation product then you are simply wasting money.

Also, when creating a well insulated building envelope it is critical to provide adequate ventilation to roof spaces and wall cavities. It you don't, then you will create a moist and damp environment which will become a breeding ground for unhealthy moulds.

Above and below are the insulation product and installation that we typically use. We always choose to use polyester insulation because it very safe to handle when installing (it is just like installing fluffy pillows), contains no formaldehyde unlike most glass fibre insulation and is made from recycled materials such as PET bottles.

Something that we are big on is trying to re-use heat and energy twice. In the case of the ducting and fan in the image below, this is not air conditioning. The simple fan and duct system transfers warmed or cooled air from one part of the house to another. So in the case of winter, a well heated living space will create and element of 'wasted' heat which we duct off and transfer to the second floor bedrooms. Those bedrooms are there fore heated virtually for free. The fan uses less energy than a single light globe and is linked to a thermostat which controls the temperature

Most people fail to realise how much heat loss or heat gain occurs through the glass in their windows. Most windows as standard have nothing more than 3mm thick glass which has no more insulating value than cling film!. In our opinion, upgrading the glass in windows is one of the most important aspects of green building.

The first step up from standard glass is to install what is called a 'Low E' coated glass. This has an efficiency improvement of around 40% over standard glass. The next step up would be to double glass your windows.

In the case of this house, we have used a Low E coated glass, below, because it provides a great combination of cost and performance for a temperate climate such as Sydney.

We simply love the look of this shot. The cladding, roof line, exposed roofing timbers and shadows.

30 August 2009

Building the eco friendly way - Roofing and cladding progress

Progress from our previous post is obvious, we now have the roof on. The roof sheeting material we have used is Colorbond Customorb metal sheeting. We have a general preference to use this form of roof material because of it's low thermal mass as well as preferring the aesthetics afforded by the metal sheeting. The metal roof sheeting also has the added benefit of being lighter weight than lost other forms of roof covering, thus reducing the load on the roof framing and leading to a more economical structure.

Directly below the roof sheeting we have installed a 75mm foil faced insulation blanket which provides a R2.5 insulation value which well exceeds the minimum requirements.

For a roof/ceiling insulation system to work there must be two levels of insulation. One directly below the roof sheeting which works to prevent heat or cold from entering a house, and the other directly above the ceiling which works to prevent heat rising and being lost out of a house.

As part of creating a well insulated and sealed building, building wrap or sisalation is required behind any external cladding as we have used above. The building wrap serves two purposes:
  • it provides a vapor barrier to keep the wall cavity free of moisture
  • it is an integral part of any insulation strategy to achieve a high overall R value for a wall system
As part of a well designed wall system, building wrap can add up to R 0.5 to the overall wall insulation level.

Keeping a roof cavity well ventilated is key to reducing the heat gain in a house during the summer. Without the ability to escape, any heat that is built up in a roof space will transfer through the ceiling and into the house increasing the internal temperature. The system we use is a series of vents that are located on the low and high sides of the roof, see the black strips in the photo above, which extract heat from the roof via natural convection, ie heat rising. So as the heat within the roof increases it will naturally rise towards the higher vents whilst cooler replacement air is brought in via the lower vents.

The plumbing first fix out has commenced and in the image above the lilac recycled grey water pipework can be seen running to a new toilet cistern. The grey water treatment system being installed will treat grey water to a Class A standard which makes it acceptable to re-use for flushing toilets, in washing machines and for watering gardens.

31 July 2009

Building the eco friendly way - Wall and roof framing progress

We mentioned previously that the intention is for the house to be self sufficient for water. The tank above is where all the potable or drinkable water will come from for the house. Based on our calculations, the tank size of 24,000 litre should be adequate for our clients anticipated water usage. A grey water recycling system will provide the water for flushing of toilets, the washing of clothes and for garden watering. So the tank above will only supply water to bathroom and kitchen taps and showers.

The erection of the wall and roof framing is progressing well. The images above show the single level, north facing living areas virtually complete. Elements of structural steel were required to facilitate the large spans across some of the window openings.

Hyspan rafters have been used for the large span living area, as can be seen below. A hyspan rafter is essentially a plywood composite beam made using low grade plantation pine timber. The beams offer a very economical means with which to create large spans with timber. The adhesive used to bind the timber is rated as E0, which is the lowest VOC emission level available.

Having completed all of the ground floor framing, above you can see the first floor wall frames and some of the roof framing being erected.

Note in the for ground the timber waste stockpile. We are really anti the waste created during construction, and so are constantly looking for ways to try and reduce any material wastage. Any waste material created is being separated into like material groups ie, steel, timber, concrete etc so that recycling is as easy as possible. Irrespective of this, waste created during construction is a big environmental problem. It is estimated that demolition and construction creates around 25% of all waste created. So long before avenues for recyling are looked at, waste should simply be reduced. We feel that we are doing a really good job of this, but as you can see in the image, it still exists.

On top of the environmental concerns is the fact that waste such as the timber above has been paid for. One might as well simply throw money into the rubbish. So reducing waste also has a bottom line, it is good for your back pocket.

08 July 2009

Building the eco friendly way - Wall framing commences

The most efficient way for timber wall frames to be manufactured is pre-fabricated in a factory. Waste is kept to a minimum, there are substantial time efficiencies due to no wet weather delays as well as cost efficiencies over frames fabricated on site. Pre-fab wall frames are made in full or part wall sections, bundled together and delivered to site as shown above. All that is left to do is erect them.

You will also note that the wall frames have a blu-ish colour. The colour indicates that the timber has been treated with Permethrin, which is an organic termiticide and provides 25 year protection against termite attack. Termites are are perpetual problem in Sydney and in our opinion you can not protect a timber structure enough from them. Generally we are not in favour of any form of chemical treatment of construction products. However, there is absolutely nothing sustainable about having a timber structure attacked by termites and a house requiring substantial repair before the end of its useful life. The permethrin does not leach from the timber and remains encapsulated in the structure of the wood, so in theory the environmental impact is minimal.

The key to using timber is for it to be either recycled or sustainably forested. In the case of the wall framing timber we are using, as you can see above, it is plantation pine which comes from Australian Forestry Standard (AFS) or FSC (Forest Stewardship Council) certified plantations.

The first wall frames go up. Standing and fixing the pre-fab Wall frames is a little bit like building a house of cards. Each frame is akin to one of the cards and as each additional frame is erected it adds to the overall structural integrity of the house.

In the background you can see the 24,000 litre rainwater storage tank for the house. The aim for the house is to be self sufficient for water, so potable water for bathing, cooking and drinking will come from this tank.

Having spent so much time and effort polishing the concrete it deserved to be protected. Being the great recyclers that we are we came across recycled carpet that had been put out for a Council kerbside clean up. Unfortunately carpet is one of those construction products that seems to always end up as landfill. It seems that no-one has found a way to recycled it. So if we can give it one more use before it ends up there, then all the better. So in the image above you can see part of the main living area floor protected with the carpet.

29 June 2009

Building the eco friendly way - Concrete polishing

Now that the concrete has fully cured, we had to finish it to a standard that we are happy to leave exposed as the finished floor. The term polished concrete is actually a little deceiving. The concrete is not so much polished as 'ground' through various grades of 'polishing stones'. Starting with a diamond grinding stone and progressing through to fine grinding stones which are a bit like sanding concrete with sandpaper. The aim for us was to create a concrete surface with a uniform grey colour and some small aggregate exposed.

The shot above shows the grinding in process. Slow and laborious with many passes across the concrete as one moves through the 'polishing stones'. The grinding can be done dry or wet, we chose to grind it wet purely because the cement dust is a health hazard that we could do without.

The image below shows the concrete surface once we had finished 'polishing' the concrete. You can see the uniform colour as well as the exposure of some smaller aggregate...perfect.

From a negative perspective, concrete polishing has the effect of wearing the finished concrete surface, thus leaving the concrete exposed to staining from anything that might be dropped on it. So a sealer needs to be applied to provide a barrier that prevents the spilt red wine from leaving a stain!

Our choice of sealer is a water based sealing compound manufactured in Australia by a paint company called Murobond. We love both them and their stuff. They have a strong environmental bent both in the products they make and their company attitude. All of their paints and finishes are either low or zero VOC, perfect for anyone planning to building green.

After curing the sealer for a week, we will be straight onto the slab and erecting the timber wall frames. Watch for the next post.

19 May 2009

Building the eco friendly way - Concrete slab pour

Most people are not aware of the significant carbon impact that the production of cement has. Production of cement accounts for 5% of the worlds carbon. This is a significant figure for what seems to be an innocuous product.

Because cement plays such a significant part in the construction of any building , if one is to truly build green, then it is important to look at ways to reduce the amount of cement used.

And one of the biggest users of cement in construction is in the manufacture of concrete. Greener concrete suppliers have now started to deal with this issue but supplanting cement content with a product called fly ash. Fly ash is a by-product from the burning of coal and makes an excellent substitute for cement. By using fly ash in concrete, what has previously been seen as a waste product now has become a valuable asset.

For this project we have used concrete from a supplier who has replaced a portion of the cement content with fly ash, significantly reducing the carbon footprint of the concrete we have used.

Because we intend to leave the concrete slab as an exposed element, it is crucial that the concrete is finished and trowelled well. Our requirement was for the concrete to receive a near burnished finish. A burnished finish is when the concrete is mechanically trowelled with a trowelling machine, as seen above, until it has cured sufficiently that the blades of the trowel are almost burning the concrete surface due to the friction of the steel blades on the concrete.

We have used a burnished finish because it provides a durable and hard wearing surface to the concrete as well as a subtle surface lustre.

Lastly, and most importantly is the curing of concrete once it has poured. Curing of concrete is one part of the concreting process that is often neglected. However, without proper curing, all of the earlier effort will be wasted. Curing it the process of preventing concrete from prematurely drying out due to exposure to the sun or wind. If freshly poured concrete is allowed to prematurely dry out, it will fail to achieve its final strength and the quality of the surface finish will suffer.

There are many ways to cure concrete, but the main methods are either the application of a chemical compound to the surface, covering the surface with plastic sheeting or permanently keeping the surface wet. We avoid the use of the chemical compound for environmental reasons and the plastic sheeting because it can mark the finished surface of the concrete. So we use a method of keeping wet hessian rolled out across the concrete surface, as you can see in the image above. Typically concrete should be cured for a minimum of 7 days, with up to 30 days ideal. Given that the finished internal floor will be the exposed concrete, we have chosen to cure the concrete for 30 days to ensure that we have the best quality surface finish.

06 May 2009

Building the eco friendly way - Concrete slab preparation

Like most concrete slabs, reinforcing bar is required to help give the slab it's strength. And like all material choices that can be made during the course of construction, one can choose to make a sustainable choice or not. In the case of the reinforcing bar we have chosen to use reinforcing bar from a supplier who uses 100% recycled steel. By using recycled steel, the environmental impact of the steel has been reduced. Recycling steel uses a lot less overall energy than mining ore, and precessing it in order to make new steel.

What is more, the strength and quality of the recycled material is the same as the new material.
The photo above shows the steel reinforcing being placed inside the form work for the concrete slab.

Timber wall and roof framing is still the dominant material for house construction in Sydney. Unfortunately this is the favorite food of one of our native creatures, termites. So it is necessary to have some form of termite protection when you build in timber in order to prevent your house being eaten out around you!

Termite protection can take many forms and more often than not involves some from of pesticide. The key is, to avoid spraying termite barriers on the soil and ground around your house. Not only are they toxic for termites, but they aren't particularly good for humans and the ground ecology.

Several new products on the market seek to address this issue by safely encapsulating a termiticide within a 'blanket' a bit like thick plastic, which can not leach the termiticide. These blankets are used to protect around pipes such as the one above, which prevent termites from entering your house by forming a physical barrier that the termites can not penetrate.

To heat the house in winter we have installed a 5 star gas in slab hydronic heating system. For those who don't know what I am talking about, a hydronic heating system is essentially heated water running through pipes, the pink ones in the photo above, which delivers heat to a location, in our case, the concrete slab.

Hydronic heating is very efficient because is works on the principle of radiant heat, which warms objects rather than convective heat which just warms the air. What is more, in slab hydronic heating is doubly efficient because the heat starts at the bottom most point in a room and rises to the top, heating everything along the way. Rather than air conditioning which generally tries to heat the air in a room from the grilles in the ceiling, down. One way is working with nature, heat rises, and the other is trying to fight it.

For in slab hydronic heating to work at its best, the floor should not have an insulating covering such as carpet or timber. So tiles or exposed concrete in our case, tend to be the best.

Above is the manifold which looks after the balancing of the hydronic heating pipework. Put simply, the two white pipes on the left are the flow and return from the gas boiler and the red is the heated water going out to the slab and the blue is the heated water returning back.

The heating system is designed as a closed loop, so the same water stays in the pipework getting heated at the boiler, then going through the red manifold and out to the slab, then back to the blue manifold and then on to the boiler to get heated and start again. Pretty simple really.