Materials

To be a viable material in a reverse veneer construction the masonry component must have a high thermal mass allowing heat to be stored and exerted at the most effective times to ensure that a constant temperature is established and easily maintained in an interior space.

Green energy bricks – green energy bricks are a relatively new material on the market and, like all new materials, bold claims of high performance ensue.

· Website http://www.greenenergybricks.com.au/

· Embodied energy – no information is advertised on there website, immediately implying that the embodied energy is high.

· Recyclability – the ability of polyisocyanurate to be recycled is relatively unproven

· Labour costs – green energy bricks are very easy to build with, they require no mortar, take up the same vertical and horizontal space as around 8 bricks and only weigh 2.7 Kg. They are also far lighter in terms of volume: mass making them easier to manoeuvre on a building site.

· Insulation qualities – green energy bricks have an amazing R8+ insulation rating. Considering that 60% of heat is lost in the average house through badly insulated walls and single glazed windows (35% and 25% respectively), the insulation qualities of a particular material is very important in terms of sustainable design

· Practicality in terms of reverse brick veneer – although green energy bricks achieve a very high level of insulation, if used in a veneer situation the wall thickness for exterior walls becomes a hindrance. The green energy brick itself is 320mm wide, combine that with a 40mm cavity 90mm stud work 10mm of plaster board and 40mm of cladding the overall thickness of an exterior wall ends up being around 500mm thick. In most residential cases this is a gross amount of area wasted on wall space, either detracting from room sizes, or adding to the buildings footprint. Green energy bricks are designed to be used as a standalone walling system. Although green energy bricks have a high insulation rating, they are not effective when trying to use them as a thermal mass. A reverse brick veneer wall requires the inner layer of masonry to store heat and exert at the most effective times . see http://www.brick.org.uk/_media/_images/about/aboutus-graph.jpg

Geobricks – Geobricks are a rammed earth, air dried bricks consisting of only 4% cement

· Website http://www.geobrick.com.au/geobrick.html

· Embodied energy – at least 2-6 tonnes less carbon dioxide emissions (CO2) on every new home compared to kiln fired solid bricks http://www.geobrick.com.au/co2-savings.html

· Recyclability – if care is taken in the demolition process, geobricks can be successfully salvaged and reused in new builds.

· Labour costs – the construction process is much the same as traditional kiln fire brickwork however the production is much more time consuming due to the fact that each brick is air dried rather than kiln fired

· Insulation qualities – geo bricks act very similarly to kiln fired brickwork in terms of insulation. R0.078

· Practicality in terms of reverse brick veneer – geobricks have the same level of practicality as kiln fired bricks in all areas except monitory.

Concrete blocks

· Website – http://www.boral.com.au/concreteblocks/concreteblocks.asp

· Embodied energy – concrete blocks are (obviously) made of concrete., which is one the leading producers CO2, accounting for 5% of the total CO2 produced by man. Concrete blocks also require mortar at every joint, contributing in the amount of cement needed in the construction process

· Recyclability – if properly demolished concrete blocks can be salvaged from buildings being knocked down and reused in new builds. Concrete blocks can also be ground down and used as an aggregate to new builds

· Labour costs – concrete block construction is relatively fast compared to clay bricks. This can be attributed to the larger size of the brick, meaning less bricks have to be physically laid to cover the same volume as clay bricks.

· Insulation qualities – R0.19

· Practicality in terms of reverse brick veneer – concrete blocks face the same problems as green energy bricks, they are vastly wider that traditional clay bricks causing impractical wall thickness when used in a veneer situation.

Traditional kiln fired clay bricks

· Website - http://www.australbricks.com.au/ , http://www.boral.com.au/ , http://www.fultonbrickyard.com.au/ , http://www.mdbrick.com.au/ for recycled bricks visit http://www.beaverbricks.com.au/ , http://www.paddysbricks.com.au/

· Embodied energy – traditional clay brick require kiln firing, (a kiln furnace is heated to around 1280˚C degrees and the clay is burned into a useable solid state). Heating this kiln requires massive amounts of energy.

· Recyclability – if care is taken during the demolishing of brick buildings, clay bricks can be washed and reused in new builds. However due to poorly constituted law, in the process of demolishing a buildings, (unlike most countries throughout Europe) you are in no way compelled (apart from having moral issues with the wastage of building materials) to conserve bricks so that they can be re-used. This is why one factor of brickwork being a large contributor to Australian landfill.

· labour cost – laying bricks is a very time consuming task due to the fact that every brick must be individually laid

· Insulation qualities – traditional clay bricks, by themselves have an R0.078 insulation rating, They are usually used in conjunction with a third party insulator and a stud frame.

· practicality in terms of reverse brick veneer – when reverse brick veneer is mentioned kiln fired clay bricks are generally implied as part of the process

I’m currently researching a few more materials that could be used for the cladding and masonry component of reverse brick veneer. I’ll post them up shortly

matt