04 How-to
Insulation Conversation More than 120 Members registered for a webinar on insulation products in April, presented by Theresa Braunsch from SPECTrum Building Energy.
Here, Theresa Braunsch answers six questions on the topic, posed by DMN Members. Q. Insulation in flood-prone buildings: PUR or PIR? A. Rigid, closed-cell insulation should be used in flood prone areas. XPS is certainly the most suitable closed-cell insulation for flood-zoned areas and will not absorb moisture, contrary to EPS. Most insulation materials will become ineffective and damaged when submerged in water for a long period of time. PIR can handle small amounts of water but can dissolve when sunk in water. It is flame- and smoke-resistant, it slows the spread of flames and reduces smoke emitted in case of fire. PUR insulation does not have the same fire-resistant properties. We should emphasise how important it is to take a holistic approach to architecture in flood prone areas, educate and seek expert advice. Floor levels should be elevated above the flood level and wall cavities accessible if possible, where insulation can be easily replaced or excessed and dried after flooding. Waterproofing membranes should be installed and act as water barriers. Manufacturer’s specifications, product performance, what environment is it suitable for, warranties and test reports should confirm the suitability of specific products. Q. Wood below floor screeds? Could you tell us more about managing termite risk? A. Referring to Wood Fibre below screed. Wood Fibre under screed insulation, which is a higher density insulation, must be managed in similar ways to any other under-screed insulation,
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with a termite membrane. The advantage of this insulation being natural, without VOC, means it has not been chemically treated, therefore could be susceptible to termites as many construction products are. HomeGuard has a range of environmentally-friendly termite protection products, which can be handled without harm to humans and are highly effective. Soil testing will determine whether an area is prone to termites and if it is the case, regular testings, post construction, should be conducted to eliminate the risk. Q. How does wood fibre (Gutex) compare, performance-wise, with straw panels (Durra panels – Australian made)? A. Both insulation manufacturers offer a wide range of products suitable for different applications, which makes it difficult to compare. The Gutex Range has around 20 products which have been tested to European standards and Australian building surveyors have the choice of accepting or rejecting its application. Most Gutex products have a thermal conductivity of 0.04 W/mK. Compressive strength can range from 50 kPa to 200kPa. Wood fibre is a very versatile product. Durra panels can be applied in walls and roofs. The panels have great fire resistance and acoustic properties. The conductivity of the natural product is 0.081W/mK, which is higher than Woodfibre and will require a thicker panel to achieve the same insulation R- value. Durra products have thermal mass properties. As Durra panels are manufactured locally, transport is not contributing to embodied energy. Both products are biodegradable and
