Browse Forums Heating, Cooling & Insulation 1 Feb 16, 2010 8:57 pm Hi all, I am investigating the viability to insulate the external walls of our new S/E Queensland home, on top of the standard sarking. First question: I am thinking of either a Brick Veneer (BV) or WeatherBoard (WB) product for our external walls. This website conveys that the insulation rating of weatherboards with r1.5 batts is similar to a brick veneer with r1.5 batts: http://www.solartex.com.au/view_article.asp?id=15&cat=7 Have I interpreted this correctly? (it also appears to remove the sarking in each 1.5 example: would this occur in practice?) Second question: In this example, lets say I have not chosen to install a/c and to ignore passive cooling. Would the heat stored in the insulation (thermal mass) be retained for longer? (Thus making the home hotter and harder to cool once the heat of the day has passed?) Third question: Most people on the forum install glasswool batts. Are their more effective materials for the external walls of BV or WB homes? Fourth question If you were to build a single story home in SE Queensland: Would you insulate the entire wall perimter to seal the house, or; Just concentrate on the walls that cop the sun's heat? Thanks in advance, Alf... Built Hallmark Home in SE Queensland - modified Flair 181 - no A/C: n/e orientation - 9 foot ceilings - copius insulation - loads of windows - fresh breeze - home... Re: Four questions about insulation... 2Feb 16, 2010 9:29 pm Hi Alf, Lots of important questions: - brick and weatherboard are both poor insulators so their insulation values are insignificant - foil works differently from bulk insulation - the former is a radiant heat barrier, the latter is a convective/conductive barrier. Foil is useful to block summer heat. It doesn't have that much effect on reducing winter heat loss. - most of the heat load comes from direct solar radiation. Foil will effectively block most of this. Quoted R value for foil don't have a lot of meaning. - the best way of reducing radiant gain is to have eaves/overhangs/shades/vegetation that block direct sun striking the walls or windows. Think of foil as secondary protection. - the rest of the heat load is from the outside ambient temperature (including the air temperature in the wall cavity). Batts will help reduce this heat transfer. Ideally the entire building envelope is covered since the effects are equal on all sides. - Having batts in your wall and ceiling will help if your winter's are cold and there is a requirement for artificial heating. - the material you choose for bulk insulation is largely irrelevant to its insulating value. The R-value is the only important factor here. However, some materials can fit more R value for a given thickness (important when installing in wall cavities). The pros and cons of glass, poly, rockwool relate mainly to environmental impact and installer OH&S. - note that sometimes too much bulk insulation can inhibit passive cooling at night. Check the Your Home technical manual for recommendations for your climate. - insulation is NOT thermal mass. Thermal mass are materials with only modest insulation but able to store a lot of heat for its given volume without becoming too hot themselves. Examples are brick, stone, rammed earth, concrete, logs. - Even with good radiant protection and insulation, a house will steadily heat up if it isn't be allowed to passively cool. This is an integral part of maintaining comfort conditions and to reduce your need for artificial cooling. Re: Four questions about insulation... 3Feb 16, 2010 10:24 pm Thankyou for the excellent response. I will read it a few more times over the next few days to get my head around the insulation of a home. Will also revist the Your Home technical manual as you recommend, Thanks again, Alf... Built Hallmark Home in SE Queensland - modified Flair 181 - no A/C: n/e orientation - 9 foot ceilings - copius insulation - loads of windows - fresh breeze - home... Re: Four questions about insulation... 4Feb 17, 2010 6:48 am Just to add . . . the 'sarking' would in practice be generally used in both situations. In a weatherboard construction it's use would purely be as a 'sarking' with a breather type foil used. In a b/v situation as it faces an air space, in theory it has a so called R value benefit of around 0.85. 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: Four questions about insulation... 5Feb 22, 2010 11:12 pm Hi all, Thanks dyno and aus for your replies. It is beginning to make sense now... - Sark the entire house to keep the heat out in Summer (thus also excluding radiant heat in winter) - Batt all external walls to keep the heat in during Winter Since I live in SE QLD, it is more preferable to maintain coolness versus retention of heat, so in addition would: - include overhangs, eaves, vegetation, external shades/blinds as primary protection - design windows to capture cooling breezes and move them through the house What about putting batts in the internal walls? (or is this overkill in SE QLD?) Thanks again, Regards Alf... Built Hallmark Home in SE Queensland - modified Flair 181 - no A/C: n/e orientation - 9 foot ceilings - copius insulation - loads of windows - fresh breeze - home... Re: Four questions about insulation... 6Feb 22, 2010 11:21 pm Internal batts for QLD is probably overkill. Which city do you live in and I will check the BOM stats. Re: Four questions about insulation... 7Feb 22, 2010 11:36 pm Hi D, Living in Brisbane. What page are you looking at on the BOM? Regards Alf... Built Hallmark Home in SE Queensland - modified Flair 181 - no A/C: n/e orientation - 9 foot ceilings - copius insulation - loads of windows - fresh breeze - home... Re: Four questions about insulation... 8Feb 22, 2010 11:45 pm alfabeta Hi D, Living in Brisbane. What page are you looking at on the BOM? Regards Alf... Go to http://www.bom.gov.au Click on QLD (top right) Click on Climate Averages (bottom of page under Climate information) Click on Brisbane (or whatever closest weather station) Click on All available button (top left hand of data table) Click on the PictoGraph (in 'Plot' column to obtain graphical representation) For your convenience here it is: http://www.bom.gov.au/climate/averages/ ... _All.shtml Hey guys building a new place through a volume builder and just wondering if i should complain to the site supervisor as we just had plasterboard installed. Looks like… 0 11254 1000000% definitely add insulation. I have in my home and it makes a big difference minimising sound transfer. Insulation is pretty cheap and definitely worth it 2 6173 |