By Tina Perinotto
The Federal Government may reverse its ban on foil insulation – imposed after the deaths of three young installers – because the problems may have been connected to installation practices rather than the material.
But even if foil is not at fault, it is not easy to discover what is the best insulation to use or the cheapest or even the safest and most fire resistant.
Archicentre, which provides free advice on housing design to consumers, said that the only generic guide for consumers is the Australian Standards at Standards Australia. Each grading – such as R3.5 and R 4 – signifies how well the material performs its stated tasks. Beyond this it becomes a question of consumer choice – that is, what price the consumer is willing to pay.
The advice does not extend to the suitability of a product or associated fire or health hazards.
General manager of Archicentre David Hallett said it was wrong to say that one type of insulation was better than another.
In the case of foil insulation he said: “You can use it, you just need to make sure you install it properly.”
There was a wide variety of choice, but no easy way for consumers to compare and select the best option for their needs.
Types of insulation ranged from batts to loose fill that is blown into a roof cavity and traditional rock wool and fibreglass.
The latest material to hit the market was a paint which is applied to the roof and reflects heat, he said.
With some insulation products Mr Hallett said there was danger that the material could reduce ventilation space around lighting, in particular down-lights, which could then cause the light to overheat and set alight nearby timber beams.
Sydney designer Jolyon Tait Sykes agreed with Mr Hallett and said and said it was common to use various materials in combination.
For instance on a busy road thick insulation such as rockwool or polyester may be useful because it would also be provide acoustic protection. In walls or floors a different material might be suitable.
“It makes sense to have a wide range of products,” Mr Tait Sykes said.
He recommended reading the websites of insulation manufacturers for guidance such as:
Were there health hazards associated with certain materials?
The manufacturers of both glass and wool fibre insulation products claim their materials are safe, Mr Tait Sykes, said [see advice from the Western Australian Department of Commerce below).
“If you look at the data sheets for both Bradford and Pink Batts glass wool fibre insulation products, they both claim to be non-carcinogenic.”
Mr Tait Sykes said an important element in dealing with thermal control is thermal mass, he said. “Dense materials such as concrete and masonry will absorb heat so if they are used internally they will take excess heat out of the air and keep the ambient temperature down.
“Of course they have a limit to the amount of heat they can store, and the spaces should also be flushed of heat at night. When the temperature drops, the heat stored in the material is released back into the room, and so should be allowed to ventilate outside or “flushed” from the space, so good cross-ventilation is important.”
He said that it was now understood that in warmer climates such as Sydney’s, insulation in conjunction with thermal mass was more effective than either on their own. A “reverse brick veneer” type of construction, for example, with timber-framed skin outside and brick inside, provides a lightweight external layer of insulation material such as batts and an internal layer of masonry.
“The external insulating layer isolates the internal space from outside heat, while the internal thermally massive layer absorbs excess heat from the spaces and maintains a lower ambient temperature.”
A note on fibreglass:
According to Western Australia’s Department of Commerce Glass wool insulation consists of fibres blown or spun from molten glass and collected in an entangled mat.
“Without a safe work procedure, these fibres can also cause short term irritation to the skin, eyes and upper respiratory tract among workers involved in the manufacture or installation of insulation products.
“Working with fibreglass fibres and dust, without safe systems of work, can result in irritation to the eyes, nose, throat and skin.
“Western Australian authorities have adopted a fibreglass exposure standard, which is among the most stringent in the world.”
According to the department the International Agency for Research on Cancer changed its classification in November 2001.
Fibreglass was now not classifiable as carcinogenic to humans and is no longer considered “possibly carcinogenic to humans” the department’s website says.
The Fifth Estate – sustainable property news