What Climate Zone am I in ? NCC Requirements for my insulation
Nation Construction Code of Australia Climate Zone Guide for Home Insulation
This map can be viewed in enlargeable form on the Energy Efficiency page of the ABCB web site at www.abcb.gov.au or directly from the Core Projects/Energy Efficiency page on the ABCB web site. In the below table you will see the minimum requirement for the “Total R Value” which, includes everything in the building between your living space and the sun. These vales are minimums for the zones referred to in the table but should be considered adequate for achieving the most cost effective beneﬁt. The figures quoted in the table below here are total system values, and not the required insulation to be effective for a ceiling. They are also only the standard as required for new buildings and not what is required for retro fitting to existing buildings
What R Value of home insulation do I need for my Climate Zone and Roof Colour
You can see from the above table in the National Construction Code (NCC) that if you have a grey or dark roof, you will need a R Value of 4.2 for summer in any of the zones 1 to 5 that cover Queensland. You will need less insulation at just R3.2 if you have a light coloured roof. You will need to adjust the required total system value of your insulation, if you have more than 0.5% uninsulated ceiling as a result of though ceiling lights. It is important to remember that this is a Total system value recommendation, and not what you require on the ceiling.
What difference Does the colour of my roof make to the insulation I need?
These tables are often misquoted by insulation sales people who are only interested in selling you more stuff. The total system value does include every part of your roof structure including the plaster ceiling, the static air space in your roof and the tiles or iron on top. It is also effected if you have roof vents like whirly birds or edmonds vents. All this being said about the R value, if you take the recommendation at the highest amount of R4.2 for climate zones in Queensland, and then subtract the R value of your plaster about of 0.26 and the air gap of about 0.75 and the rooﬁng material itself the you are down to about R3.0, this is without taking into consideration your ventilation or roof colour and that is why the National Construction Code (NCC) recommends R2.5 for on ceiling insulation in Queensland.It is also why I am very conﬁdent that at 20% more than the recommended standard for insulation on the ceiling, Comfort Zones minimum standard of R3.0 will stop the heat very well and selling more than you need is just wrong
What Difference do Roof Vents make to my homes R value?
It is stated in the code that a properly ventilated roof (Approx. One vent per 70 square meters) will only make a R Value difference of Just R 0.09 to your home (as indicated in the table on the right - the difference between ventilated and non ventilated roof). Even in the National Construction Code (NCC) quotes the most difference roof vents make to the Thermal resistance of your home is a R value of just 0.18 (0.74-0.56) when properly installed and only considered in summer time for downward heat transfer. In Winter time this becomes a negative R value of 0.18 as shown on the table beside for a standard tile roof.
I think you would agree that it is a very small difference and it has a negative effect during winter because they will be sucking the heat out of your home. That is why I do not recommend roof vents (Other than all the other problems roof vents like whirly birds will cause). The other important thing to take into consideration is that during summer storms, any vents on your roof will become the weakest spot and they often get just one little hit by debris and start to make noise or leak.
What Difference does Foil insulation like Anticon Blanket make ?
Have a look at the table below that is straight out of the National Construction Code (NCC), it rates foil at about the same effectiveness as changing the colour of your roof from black to white!
It should be mentioned that Foil insulations are not very effective at cooling a home in summer, and have no ability to warm a home in winter other than the effect of putting any barrier that slows convection as there is no radiated heat in your roof. Even if there was radiated heat in your roof, once dust gets on the foil are you going up there to clean it off?This is why out of all the insulation on the market Foil is the only one that I am not prepared to sell as I have never seen it work in a real roof over the long term.www.abcb.gov.au - Ref - NCC2016-BCA-Volume-One.pdf