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Types of insulation products
Australian Standards cover most insulation products. Provided the product complies with the Australian Standard, good levels of performance and reliability can be expected. If no Australian Standard exists, it is vital to ensure the product has been independently tested to ensure performance is optimised. This should be done in a National Association Testing Authorities-accredited laboratory.

Bulk insulation
Bulk insulation contains millions of tiny pockets of still air trapped within the material. This air provides the material’s insulating effect so it is important not to compress bulk insulation. Bulk insulation is available as batts, blankets and boards, or as loose fill which is pumped, blown or placed by hand into an area.

Batts and blankets
Glasswool (fibreglass)
> Made from melted glass spun into a flexible mat of fine fibres
> Available as batts or blankets
> Easy to cut and install
> Commonly sold in DIY packs with R values clearly labelled
> Should not be compressed or moistened
> All ends and edges should be butted together firmly during installation
> Blankets are manufactured in rolls for specific types of installations, e.g. under roofing in a cathedral or raked ceiling or under a flat roof
> Blankets are thinner and denser than batts, and are available with reflective foil attached to one side

Rockwool
> Made from volcanic rock melted at high temperatures and spun into a mat of fine fibres
> Available as batts or blankets> Denser than glasswool, so R value per unit thickness is higher
> Better sound absorption qualities than glasswool
> Generally more expensive than glasswool

Other characteristics are similar to glasswool
Glasswool and rockwool are together referred to as ‘mineral wool’ products. Due to their potential to irritate the skin and the upper respiratory tract, full protective clothing, including gloves and a face mask, should be worn during installation.

Natural wool
> Made from sheep’s wool formed into batts or blankets
> Should only be manufactured from new, scoured wool treated with a vermin and rotproofing agent during the scouring process
> Moth-proofing of wool is vital—check with the manufacturer for test results to guarantee this (test results should not be more than four months old)
> Most batts and blankets are made of a wool polyester blend to reduce settling and
compression
> Naturally flame-resistant, however, the addition of synthetic fibres increases flammability—check with supplier for fire resistance testing results
> As different types of wool can provide different R values for the same thickness, check with the supplier for R value tests and certifications

Polyester
> Made from polyester fibres (including recycled PET bottles) spun into a flexible mat
> Available as batts or blankets
> Similar physical properties to mineral wool, but is non-irritable, with no known physical or health hazards
> Does not burn, but will melt if exposed to a direct flame at high temperature

Loose-fill insulation
This type of insulation consists of shredded or granulated material supplied in a loose form, and is usually installed by the supplier/manufacturer. It must be correctly installed at even depth to provide adequate insulation cover. Barriers should be installed to prevent insulation falling down through exhaust fans, wall cavities, ceiling vents and light fittings.
Loose-fill material may settle over time, reducing its effectiveness—your contractor should quote you a guaranteed ‘settled R value’, which is the final R value achieved after any settling has occurred.
This type of insulation is more suited to flat or shallowly-sloping ceilings of less than 25° pitch.
With the exception of some rockwool products, loose-fill is only suitable for insulating ceilings.

Cellulose fibre
> Made from waste paper pulverised into a fine fluff
> Must be treated with fire retardant chemicals to reduce flammability
> Cheaper to purchase and install than other types of bulk insulation
> Quality and installation can vary greatly, so ensure the product complies with Australian Standard AS2462 (1981): Cellulosic fibre thermal insulation

Natural wool
> Natural sheep’s wool off-cuts
> Should consist of pure, new, scoured wool only—should not contain any synthetic fibres, or dyed or recycled materials
> Cheaper grades of wool are commonly used and can include small leather fragments—this should not affect performance
> Should be treated with a vermin and rot proofing agent during the scouring process
> Other characteristics are similar to natural wool batts and blankets

Granulated rockwool
> A loose-fill form of rockwool
> If treated with a water-repellent agent, can sometimes be used to fill cavity brick and brick veneer walls—check with the supplier to see if it is suitable

Boards
These are used mainly in walls and cathedral ceilings.

Extruded polystyrene
> Rigid, waterproof boards of closed cell polystyrene
> High compressive strength
> Contain flame-retardants, however, installation is only recommended between non-combustible surfaces (e.g. plasterboard, reflective foil or brickwork)
> Very high R value per unit thickness
> Generally more expensive than other types of bulk insulation
> Some products available with reflective foil backing

Foil-faced expanded polystyrene
> Rigid boards of polystyrene beads with reflective foil attached to both sides
> Should be installed with foil facing still air spaces of at least 25 mm width to maximise R value
> Expanded polystyrene has lower R value per unit thickness than extruded polystyrene
> Also available as boards without foil facing—these have similar properties to extruded polystyrene, but have lower compressive strength and are not water resistant

Reflective insulation
Reflective insulation is made of thin sheets of highly reflective aluminium foil laminate, which reflects heat from its polished surfaces while absorbing and emitting only a small amount. It must work in conjunction with a still air layer for maximum effectiveness (see figure 7.6).
An R value supplied by reflective foil insulation is equivalent to the same R value provided by bulk insulation. Reflective foil R values are influenced by the characteristics of adjacent air spaces, such as their orientation, thickness and temperature differences.
Adequate performance can be achieved by combining reflective insulation with bulk insulation and/or using specialist foil products, provided they are carefully installed. Any gaps or tears will significantly reduce performance, as will dust build up on surfaces. Four types of reflective insulation products are currently available.

Reflective foil laminate
> Foil laminated to paper with glass fibre reinforcement
> Supplied in rolls
> Typically used as roof sarking and wall insulation
> Double-sided foil is more effective than single sided, provided that both sides face a still air space; it is also more water resistant
> Double-sided foil is typically produced with an anti-glare coating—this reduces the insulation’s effectiveness by around 10%

Multi-cell reflective foil products
> Two, three or four layers of laminated foil separated by partitioning to provide a one, two or three-layered cell structure
> Can be installed over ceiling joists and between or across wall studs, depending on the product
> Should be butted firmly together to prevent air movement through gaps
> R value depends on the number of cells and the presence of still air layers between the batts and other materials

Expandable concertina-style foil
> Double-sided reflective foil formed into an expandable concertina
> Used mainly under timber floors and between wall studs
> Adjustable width to suit varying gaps
> Should be installed with an adjacent sealed air space and be well sealed against the building frame

Foil bonded to bulk insulation
> Reflective foil bonded to batts, blankets or polystyrene boards
> Increases insulation benefits if installed with the foil facing a still air space
> Blankets are a common method of insulating cathedral ceilings and under flat roofs

Soundproofing
Some insulating materials can be used for soundproofing. Bulk insulation, particularly denser materials such as rockwool, has good sound absorbing qualities. The soundproofing performance of a particular product is measured by a sound reduction index referred to as Sound Transmission Class (STC). The higher the STC rating, the greater the soundproofing performance. If soundproofing is desired between rooms (e.g. between a bedroom and a bathroom), high density insulation can be installed in internal walls or between floors in a two-storey building. Blanket type insulation installed directly under metal roofing also helps reduce external noise caused by wind, rain and hail. Specialised acoustic insulation products are also available which provide even better soundproofing performance.

Overall R value
The overall R value is the total resistance of a building element. It takes into account resistance provided by construction materials used in a wall or ceiling, internal air spaces, thermal bridging, insulation materials and air films adjacent to solid materials. Each of these components has its own inherent R value, the sum of which provides the overall R value.

Added R value
The added R value or added thermal resistance is the value of the insulating material alone. This is the term most used when buying insulation. The manufacturer should provide the R value of bulk insulation. Some products will trap air or gas more effectively, and so will have a higher R value for a specified thickness. For example, 45 mm thick extruded polystyrene and 80 mm thick glasswool both have an R value of approximately 1.5.
Reflective insulation must work in conjunction with enclosed air spaces between surfaces, and cannot be said to have an R value by itself. To compare the performance of bulk and reflective insulation, the resistance of any existing air space(s) must be calculated. Reputable manufacturers can supply this information. Note that the effectiveness of reflective insulation installed on horizontal or sloping surfaces will eventually be reduced due to dust build-up, which reduces reflectivity.

Thermal bridging
Thermal bridging is the transfer of heat across building elements, which have less thermal resistance than the added insulation. This decreases the overall R value (see figure 7.8).
Wall frames and ceiling joists are examples of thermal bridges, having a lower R value than the insulating material placed between them. Because of this, the overall R value of a typical ceiling is reduced. For example, adding R2.5 bulk insulation between timber joists will result in an overall R value for the whole ceiling of R2.2. Metal framing, which has lower thermal resistance, reduces the overall R value even further. Consequently, higher levels of added insulation must be installed to compensate for this.

Insulation levels
Minimum insulation levels for Victoria
Whilst minimum thermal performance requirements are standard practice in many countries, Victoria is the only state in Australia to currently set minimum insulation levels. A national framework has been developed for House Energy Ratings which will
address insulation as one of several components. In March 1991, government regulations were introduced specifying minimum insulation levels for all new homes and extensions built in Victoria.
Small alterations or renovations to existing buildings requiring a building permit may also have to comply with the regulations, depending on the local council.
The regulations ensure that a reasonable level of thermal insulation is incorporated into residential buildings. New buildings of classes I, II and III (includes all residential dwellings such as homes, flats and units, and the residential sections of hotels, motels, schools, special accommodation and health-care buildings) must reach these
prescribed insulation requirements.
The regulatory requirements may be met by:
> complying with either of the following two basic options shown in table 7.2; or
> achieving a House Energy Rating of at least 3 stars and at least equivalent to that which would be achieved using option A or B (see table 7.2), as assessed by a registered building practitioner accredited in the use of the Sustainable Energy Authority’s FirstRate house energy rating software. Common building materials, such as brick, timber or tiles have little inherent insulation value. The R values of some typical forms of wall construction are shown in Table 7.3. The regulations require a minimum R value of 1.3 for walls. Only 200 mm aerated concrete meets the Victorian minimum insulation requirements by itself. Brick veneer and weatherboard walls have R values of 0.51 and 0.53 respectively, thus needing the addition of insulation to comply with the regulations.

source http://www.sustainability.vic.gov.au/resources/documents/Insulation_types.pdf