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.