Browse Forums Heating, Cooling & Insulation Re: is insulation on a new build mandatory? 2Feb 11, 2016 1:51 pm Peter Clarkson - AusDesign Australia www.ausdesign.com.au This information is intended to provide general information only. It does not purport to be a comprehensive advice. Re: is insulation on a new build mandatory? 5Feb 11, 2016 2:36 pm Peter Clarkson - AusDesign Australia www.ausdesign.com.au This information is intended to provide general information only. It does not purport to be a comprehensive advice. Re: is insulation on a new build mandatory? 10Feb 25, 2016 2:34 pm Peter Clarkson - AusDesign Australia www.ausdesign.com.au This information is intended to provide general information only. It does not purport to be a comprehensive advice. Re: is insulation on a new build mandatory? 11Feb 25, 2016 5:27 pm Foremost Building Expert in Australia,assisting with building problems/disputes, building stage inspections,pre-contract review advice for peace of mind 200 blogs http://www.buildingexpert.net.au/blog Re: is insulation on a new build mandatory? 13Feb 25, 2016 9:11 pm Stewie D The R2.5 batts in the wall, were they HD to enable them to be fitted in a 90mm timber framed wall ? Stewie not sure I will check when I am there next Foremost Building Expert in Australia,assisting with building problems/disputes, building stage inspections,pre-contract review advice for peace of mind 200 blogs http://www.buildingexpert.net.au/blog Re: is insulation on a new build mandatory? 14Feb 25, 2016 9:33 pm Similar to BE, HOUSE insulated to the hilt and after living in temporary poorly insulated rental for two years, the difference in temperatures in both winter and summer is huge,and rental was 16squares and new house 40 odd squares, 16 square rental electrical bill $550, 40 square new house $340 , , and rental nearly always super cold in winter and super hot in summer, while new house is just so comfortable all the time, better insulation will mean so much more comfort all year Re: is insulation on a new build mandatory? 15Feb 26, 2016 8:48 am Thought for the last day of the week – how many people are requiring breather foil to be installed to the envelope of their home rather than standard RFL ? With homes becoming increasingly ‘air tight’, vapour moisture build up or ‘wall cancer’ is going to become a major subject for discussion. Peter Clarkson - AusDesign Australia www.ausdesign.com.au This information is intended to provide general information only. It does not purport to be a comprehensive advice. Re: is insulation on a new build mandatory? 16Feb 26, 2016 1:23 pm I get the impression there's generally a poor understanding of the vapour permeability requirements and the properties of various sarking / wall wrap products. I think many builders are still quite happy to put in non-permeable RFL (reflective foil laminate) without thinking of the moisture implications. Then most of the wall-wraps have the reflective side on the inside, which is the wrong way around for insulated brick-veneer construction. Re: is insulation on a new build mandatory? 17Feb 26, 2016 1:47 pm Quote: Thought for the last day of the week – how many people are requiring breather foil to be installed to the envelope of their home rather than standard RFL ? With homes becoming increasingly ‘air tight’, vapour moisture build up or ‘wall cancer’ is going to become a major subject for discussion. I've been specifying breather foil over normal sarking for the last ten or so years for any of my jobs Peter after seeing a home only a few years old where a lot of the weatherboards had started to rot because of moisture buildup on the inside. I also gleaned this a while back... "Reflective foil insulation should not be placed on top of ceilings or ceiling joists, nor under floors, as it is electrically conductive. Any such insulation must also be secured with non-conductive staples." Quote: Then most of the wall-wraps have the reflective side on the inside, which is the wrong way around for insulated brick-veneer construction. Too true onejohn unless you live in a cold area like Tassie. Stewie Re: is insulation on a new build mandatory? 18Feb 28, 2016 10:12 am Most people have a very over simplified understanding of insulation. In my view this is largely driven by the over-simplified and often counter-productive way that it is addressed in the building code and other building regulations and publications. This is probably because land developers and building industry representatives sit on the codes board and it is more profitable for them to build insulated air-conditioned boxes on tiny blocks of land, than well designed passive homes on slightly larger blocks. This has lad to a general impression that more insulation is better. This is not necessarily the case. It is contingent upon the local climate and the intention of use of the building, and of course the architectural design of the building. If you live in a very hot or cold climate, and you intend on using active cooling and heating (air con, central heating etc) for a significant part of the year, then yes, lots of insulation will maximise the efficiency of that building under those circumstances and operating conditions. Rules of thumb are ok to an extent, but in my view each home needs to have its energy performance modelled over the course of a year by an expert (e.g. a university qualified energy engineer or similar, not someone who's done a 2 week energy rating course...). We got involved on a high rise office building in Sydney where on the advice of an energy efficiency consultant (who had done said 2 week energy rating course) that they should put reflective tint on all of their glass (about 10 storeys, 4 sides of the building). Rather than their energy bills going down, they actually went up because the air conditioning was working so much harder to heat the building during winter because the warming sun was blocked out by the tint.... EPIC FAIL. So they engaged us as professional engineers to actually calculate and model the energy performance of the building like they probably should have done the first time. The funny thing about energy performance is that often things that might seem "common sense" actually don't work, or have a negative impact. Unless you consider every aspect together as part of a system, one energy efficiency measure might negate another measure. If you live in a fairly stable, moderate or warm climate, and you want to minimise your use of active heating and cooling, then adding more insulation could actually be counter productive. For example, if your house is sitting there baking away in the heat all day, eventually it will get hot inside no matter how much insulation you have. But once the sun goes down, the house will take much, much longer to naturally cool itself due to the level of insulation. Conversely in winter, you want try to and use the sun to your advantage to warm your home, so too much insulation can keep out the warmth of the sun as it heats up thermal mass (e.g. a masonry wall). My understanding is that Perth has a generally warm, dry climate. This is an ideal place for passive design. A house with big wide eaves to shade the walls during summer but not too wide to ensure that the low winter sun can heat the house in winter, lots of big openable windows, ceiling fans throughout, and plenty of roof insulation to keep out the heat of the sun. Maybe a central evaporative cooler for those very hot days... The point I'm making is that insulation is only one part of the overall solution of energy efficiency, and you can have a more energy efficient house without prolific wall insulation depending on the architectural design of the building and the local climate. In my view it is best to design the house to make the best use of the climate, rather than trying to fight against the climate - in the end, nature always wins. Of course it also depends a very large amount on how you actually USE the building. Building Services Engineer Renovating our 1960's modernist home in Brisbane https://forum.homeone.com.au/viewtopic.php?f=53&t=82091 Re: is insulation on a new build mandatory? 19Feb 28, 2016 11:22 pm oneJohn I get the impression there's generally a poor understanding of the vapour permeability requirements and the properties of various sarking / wall wrap products. I think many builders are still quite happy to put in non-permeable RFL (reflective foil laminate) without thinking of the moisture implications. Then most of the wall-wraps have the reflective side on the inside, which is the wrong way around for insulated brick-veneer construction. The direction of the silver side makes very little difference to performance as both sides are low emissivity - one side is just a bit shinier with a bit less emmisivity. More important to get an air gap on both sides - and how many people do that? In BV most people end up with a gap only on the brick side. In my retrofit I put the reflective side on the inside on the south wall and on the outside on the north wall, but either way works fine. These days many people are recommending a highly vapour permeable barrier such as Proctorwrap. Much more permeable than even breathable foil. Re: is insulation on a new build mandatory? 20Feb 29, 2016 12:24 pm Joynz The direction of the silver side... This depends on the product. Some have low emittance on both sides, and some only on one side. If it has a low emittance surface on the outside, it is usually dulled to avoid blinding the bricklayers during construction, whereas for inward-facing they usually have a straight foil. The main thing is that for a low emittance surface to work, it needs an air gap next to it. So for brick-veneer, the most practical solution is to fill the frames with R2.5 batts, and not bother with a low-emittance surface on the inside, but instead use the outer surface into the cavity void as the radiant heat block. With one low-emittance surface on the outside operating against the cavity, you still reduce radiated heat transfer in both directions. Inbound heat is reflected, and outbound heat is also reduced as the low-emittance surface doesn't emit as much radiated heat when the inside heats up. This is why downward-facing foil works in roofs: as it stops the heat being radiated downward, but upward-facing stops working once dust settles on it. The only product I found that was vapour permeable and also had a low-emittance outside surface was HardieWrap, but presumably there would be others that do this. Back to the original topic, having the double-sided foil wrap is something of a substitute for having bulk insulation, so perhaps OP has this as a means of meeting the energy rating requirements. I am saying that double brick has similar thermal performance due to thermal mass effect. It will be still very interesting to see the state of your framing after 10-15… 10 29659 |