Search all WA Government Sites Print this page	[ Selecting Insulation ] [ Types of Insulation ] [ Installation and Safety Tips ] Bulk Insulation Cellulose fibre Composition: Finely shredded recycled paper. Borax and boracic acid are added as fire retardants and to deter insects and rodents. Cellulose fibre is pumped or blown into ceilings by contractors to the required depth for the R value purchased. Depending on the installation method, this material may settle over time with an associated reduction in performance. It is recommended that your contract guarantees the compacted depth and R value. Glasswool (fibreglass) batts Composition: Melted glass spun into a mat of fibres. Batts with different R values are available. Fibreglass batts are flexible and easily cut and installed by a householder or a contractor. A dust mask, gloves and a long sleeved shirt should be worn during the installation process. Fibreglass blankets with foil backing are also available and are typically used under the roof as insulation and a moisture barrier. Gaps around and between the edges of batts can impact on the overall effectiveness of insulation. If you choose batts make sure they are installed without gaps. Polyester batts Composition: Polyester fibres spun into a mat. These are similar to fibreglass batts, except that polyester is not known to cause irritation during installation. Foil-backed polyester blankets are also available. Polystyrene foam boards Composition: Polystyrene shaped into boards. These have excellent insulating properties. They can be used in double brick and brick veneer walls and against solid concrete and rammed earth walls. Rockwool Composition: Melted volcanic rock (basalt) spun into fibres. Available in loose fill form for vertical wall cavities and as batts and blankets for ceilings and frame walls. Rockwool is denser than fibreglass and possesses superior thermal and acoustic insulation properties. The same precautions should be taken when installing rockwool as when installing fibreglass. Wool Composition: Wool. Wool is a natural material with good insulation properties. Only fully scoured wool that has been treated with a vermin and rot-proofing agent should be used - for fire safety and to prevent infestation by insects. It is available in the form of loose fill, batts and foil-backed blankets. The R value of wool is dependent upon the density at which it is installed. It is therefore important to ensure that it is installed at the required density by an experienced contractor. The density of wool insulation is also often quite low, which means that a greater thickness of insulation is required to achieve the same R value as other more dense products. Reflective Insulation Reflective foil laminate Composition: Usually metallic foils, laminated to paper and reinforced with glass fibres. This is supplied in rolls and often used as both a vapour barrier and insulation. Double sided and single sided foils are available. To optimise their effect, the shiny metallic surfaces must be adjacent to a still air gap of 25 mm or more. Some types of double sided reflective foil have an anti-glare coating (often blue) on one side to make installation safer in sunny conditions. This coating reduces insulation performance by a small amount. Any holes or joins in the foil or any gaps around the edges will affect insulation performance and should be taped up. Dust build up on shiny surfaces will also affect performance. Reflective foil with bulk insulation blankets Composition: Usually reflective foil laminate bonded to glasswool. These are typically used under the roof as a condensation barrier and insulation. As with normal reflective foil, the insulation performance will be highest if the foil faces a still air gap. Expandable foil batts Composition: Double-sided reflective foil laminates folded into an expandable concertina form. These can be cut to fit between wall studs and floor joists and are stapled into place where they must fit tightly against building frames. Perforated expandable foil batts that allow the free passage of moisture can be used under timber floors. Multiple foil batts Composition: Several layers of double-sided foil held apart by separating strips to form a layered cell structure. These batts can be installed over ceiling joists or between wall studs. They must be butted firmly against each other and against building frames to prevent airflow. In ceilings the batts may sag over time and become slightly less effective. Covering ceiling joists can also create a safety hazard by obscuring safe footing positions. Other Insulation Products The range of products listed is not necessarily comprehensive, with other products available on the market at any time. When choosing any insulation product, remember to ask about the R values for both summer and winter performance relevant to your requirements and if any performance guarantees or test certificates are available from reputable authorities. It is also important to consider other properties such as durability, fire safety, installation safety and pest resistance. Building Materials Building materials have varying insulating properties. Aerated concrete bricks and panels, some wood fibre boards and pre-fabricated wall panels comprising a sheet of polystyrene foam sandwiched between two lining boards, such as plasterboard, are all good insulating building materials. Paints and materials that are white or light coloured can help keep houses cooler in summer by reflecting the hot sun. Special insulating paints are marketed but presently there is no conclusive proof that their reflectivity is significantly better than a high quality white paint. Paint does not have any insulating properties itself and should not be used as a substitute for appropriate insulation. Where to from here? Use the information in this pamphlet to assist you to decide which insulating products are suitable for your particular application and estimate the R value you require. Look up the Yellow Pages or local newspaper and contact a few insulation suppliers. Check the price per square metre, the R value of the material, whether it is installed professionally or DIY, and any other advantages or disadvantages of their particular products. Ask if any performance guarantees and test certificates are available for the products. Based on all of these factors choose which insulation is best for you. As in any purchase, check to make sure you get what you pay for, especially the thickness of the insulation and the absence of gaps in the installation. Finally, follow manufacturer's instructions on the correct installation, safety and care of insulation products.
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