Latest News

AccuRATE V1.1.3.0

The latest version of 2nd Gen BTP Assessment tools has been released.

DoP agree to a new Pilot to commence early February 2007.

BASIX (DIY) Review

ABSA instrumental in securing DoP DIY Sustainability Tool - DoP Review...not independent but a starting point

Visit the ABSA Site for further details.

DIY found to lower the standard of Residential Building BTP in NSW - varies between 200% to 400% below Simulation Method when compared with NatHERS and far more variation expected to AccuRATE.

ESD materials

Embodied Energy

Inherent in the wastage of almost any material is associated energy that was used in its making: energy used in extraction of raw material from the environment energy used for transportation energy used during manufacture energy used again for transportation energy used in its placement in the building and energy used in demolition.
In order to amortise the energy used it would be prudent to recycle or reuse the material to avoid at least some of the energy used in extraction manufacture use and in the waste streaming.

The subject of embodied energy requires adequate space for explanation and is a topic worth publication in its own right. As a guide the following tables haves been included here for reference and as a guide only:

Embodied Energy (Process Energy Requirement or PER)

Organics	MJ/kg	Ceramics	MJ/kg	Metals	MJ/kg
Kiln dried sawn softwood	3.4	Stabilised Earth	0.7	Mild Steel	34.0
Kiln dried sawn hardwood	2.0	Imported dimension granite	13.9	Galvanised Mild Steel	38.0
Air dried sawn hardwood	0.5	Local dimension granite	5.9	Aluminium	170.0
Hardboard	24.2	Clay bricks	2.5	Copper	100.0
Particleboard	8.0	Cement	5.6	Zinc	51.0
Medium density fibreboard	11.3	Gypsum plaster	2.9
Plywood	10.4	Plasterboard	4.4
Glue-laminated timber	11.0	Fibre cement	7.6
Laminated veneer lumber	11.0	Insitu concrete	1.9
Plastics general	90.0	Precast steam-cured concrete	2.0
PVC	80.0	Precast tilt-up concrete	1.9
Synthetic rubber	110.0	Concrete blocks	1.5
Acrylic paint	61.5	Autoclaved aerated concrete	3.6
		Glass	12.7

Embodied Energy (Process Energy Requirement or PER)

Walls Timber frame timber weatherboard plasterboard lined wall Timber frame reconstituted timber weatherboard plasterboard lined wall Timber frame aluminium weatherboard plasterboard lined wall Timber frame clay brick veneer plasterboard lined wall Steel frame clay brick veneer plasterboard lined wall Double clay brick plasterboard lined wall Cement stabilised rammed earth wall	MJ/kg 188 377 403 561 604 472 376
Floors Elevated timber floor (lowest level) Elevated timber floor (upper level) 110 mm concrete slab on ground 110 mm elevated concrete slab (permanent formwork) 200 mm precast concrete T beam/infill flooring	MJ/kg 293 147 645 665 644
Roofs Timber frame timber shingle roof plasterboard ceiling Timber frame concrete tile roof plasterboard ceiling Timber frame terracotta roof plasterboard ceiling Timber frame steel sheet roof plasterboard ceiling Steel frame steel sheet roof plasterboard	MJ/kg 151 251 271 330 483

The concept of an environmentally damage free material presupposes that:-

no extractive processes are required to secure the base materials
the material is renewable
the material is applied to building construction with low energy demands
the completed building system has good comfort and aesthetic performance
at the end of the building's life the material can be returned to the environment without residual damage, or can be recycled to be used again in another new building development.

Existing Systems

Working within existing available building systems, materials choices may be made where very few of the above attributes are secured directly, or other pragmatic priorities possibly with environmental consequences might be added to the list.

This practice uses a substantial amount of steel in some projects.
Normally such a material derived from extractive mining, with high energy inputs to form the material and further form useable products from the material and its fabrication requirements would be judged environment unfriendly.
However the driving priorities favouring steel in a pro-environment context included:-

that the building could be substantially pre-fabricated and erected on-site initially with only hand tools,

erected on-site from within the final building 'footprint' with minimal damage to the surrounding site

erected with minimal support machinery until the renewable energy system is operating on the building which then powers the support machinery rather a generator

that pest invasion and attack is minimised as a consequence of use

Such materials are readily available, well understood by industry and regulatory authorities; and approvals are achievable; although advocacy is needed for these less usual applications of materials made by this practice (notably the use of light industrial steel sections for residential structures).

Assumed to be 'environmental'

The practice also has been involved with the use of materials usually associated with favourable environmental performance: recycled timbers, stone salvaged from on-site, stabilised rammed earth using site excavated material to bench the building, mud brick and aerated autoclave concrete.

Some regulatory authorities have little experience with some of these, and it is not unusual for advocacy to be needed on individual concerns raised by such regulators.
These concerns include: the structural capacity of recycled or handmade materials, waterproofing of surfaces and materials, guarantees as to definition of colour of surfaces of material embodying natural materials in the completed building.

None of these concerns has a real basis in; it is more usually only the unfamiliarity with the material and its applications by the outside observer which causes concerns or objections.

Fully renewable material

An example of an emergent ecological material is straw bale construction.
There are few local examples of this construction; expertise, prior examples, draft building codes and so on are all sourced from overseas.
As a result local building industry and authorities are perplexed by proposals embodying these materials. Approvals are obtainable by energetic advocacy including the ESD merits and the local application of precedent, technology and experience from elsewhere.

Why devote effort to such building construction?

This building system embodies most of the desirable ecological material priority characteristics:-

the material is sourced from waste in the normal agricultural process, being the remnant stalk usually burnt or turned into the soil

new material is generated in the farm rural cycle each year

the material is biological, with no extraction processes needed

the material achieves R6 insulation characteristics

at the end of the building life, the material is returned to the environment by mulching
technology, existing buildings, and draft building codes information is centred in the US.

The most commonly asked questions about straw bale construction material relate to :-

structural safety
fire
vermin
moisture

None of the purported characteristics of any of the building material claimed are found in the reality.
The complete building system includes straw in a pressed and bound bale with fire retardant applied as for cellulose insulation, (boric acid) and an external fire resistant render skin. The building system as a whole does not support combustion.
Vermin find the hollow cellulose structure of the straw bale unpalatable due to the low cellulose density and regular air pocket in the matrix of the material. Vermin is also excluded by damp proof course and render envelope which are part of the building system.
The rendered envelope and damp proof membranes built in as for other masonry systems means that the system is not subject to water ingress or logging.

Similar to other masonry systems, the material can be erected as infill to a framed building, or as load bearing masonry.
In either system the material is internally reinforced with pins between bale layers, and externally reinforced with mesh in the render envelope.

There is substantial local experience with 'Dri-bond' walls where loose stacked hollow concrete blocks form the core and a glass reinforced render envelope provides structural rigidity.
In load bearing construction for straw bale, the external reinforcing and render fulfils the same role; additionally full height tie rods and a wall plate bond beam is integral to the straw bale system of construction as for autoclave concrete walls.

Thus all of the characteristics of straw bale construction are as found in other conventional masonry systems.

There is some settlement in wall height during construction of load bearing straw walls, and the tie down and bond beam design allows for this.

There is nothing alien or technically difficult in the building system.
Successful application depends on design understanding the system features, and construction practice allowing for these issues.

Traditional construction systems, notably kiln fired masonry situated on reactive soil sites, have a long history of problems in use;
including substantial cracking prejudicing structural integrity, but this hasn't stopped their use.