Browse Forums Heating, Cooling & Insulation 1 Aug 13, 2009 10:07 pm Hi all i am thinking to add better R rating to my house. can anyone suggest me, what's the best way to add better insulation as well as to sound proof it (from external noise, as well to prevent the HT sound not to go out) my builder standard inclusion External Walls - R1.5 Foil wrap Ceiling - R3.5 therma blow in wool i have some rooms that facing west, so my builder advised me to use Rockwool on the west side (about 12.5m in length), they quoted me with additional $250 based on that fact, i also asked to be quoted with additional rockwool on HT room, which is about 4 x 4.3m, for 3 sides, i was quoted with $750 that's expensive ! Is it actually worth to get rockwool ? i read somewhere, rockwool will add insulation to R2.0 for walls, so from R1.5 to R2.0 isnt going too much difference. what do you guys think ? many thanks Final stage Re: I want to increase my Wall R rating without blowing $$$ 2Aug 13, 2009 10:41 pm d3p Hi all External Walls - R1.5 Foil wrap R1.5 to R2.0 isnt going too much difference. what do you guys think ? many thanks Foil is best for keeping solar radiation out, not heat in. I think attributing an R value to a radiant barrier is a bit meaningless. Foil is a great conductor and what you don't want is for the heat to conduct out of the house during winter. If you want to keep the warmth in you will need something more than a bit of foil. Re: I want to increase my Wall R rating without blowing $$$ 3Aug 13, 2009 10:47 pm hi dymonite69 thanks for the response oh that's a surprise that foil doesnt do anything to keep the warm inside the house that's tricky from the builder, last thing that i want to hear is excuse the house wont meet 5 energy rating ! what my builder "told" me is... we leave the draftsman to calculate the energy rating etc.... but we will be on 5 star energy rating. i knew that "word" isnt enough can you suggest anything? does it mean it's better if i request for having a glasswool or rockwool in addition to the foil wrap? so foil is for the reflective, then rockwool to keep the temperature within the house? Final stage Re: I want to increase my Wall R rating without blowing $$$ 4Aug 13, 2009 11:01 pm d3p hi dymonite69 thanks for the response oh that's a surprise that foil doesnt do anything to keep the warm inside the house that's tricky from the builder, last thing that i want to hear is excuse the house wont meet 5 energy rating ! I don't think the builder is being deceptive, it's just an odd way the BCA describes the material. Personally I think the energy efficiency codes are a bit simplistic and misleading. Most houses need batts and foil it is the most appropriate thing in a mixed climate. If you live in North Queensland or the NT then you might get away with batts. We have both foil and R 2.0 batts (the highest you can fit within a standard 90mm stud wall). You really don't want the shiny side of the foil to touch anything, otherwise it loses its effect. Foil does have some winter warming effect by reducing indoor radiation but this is a tenth of the solar radiation striking the building. However, most of the heat loss is via convection or conduction. You can use polystyrene, fibreglass, rockwool, polyester or cellulose fill. Re: I want to increase my Wall R rating without blowing $$$ 5Aug 14, 2009 10:35 pm hi dymonite69 thanks for the explanation well, if my builder is going to use only foil wrap, definitely it's enough ! I wonder how they able to ads the rating as 5 star ? R2.0 is the highest i can get for 90 mm wall ? hm then i need to speak to my builder to put batts into the wall... i can sense there will be extra cost.... but if it's worth for it then so be it. thanks for your explanation about the ceiling, therma blow in wool. the inclusion seems to be reasonable good ? R3.5..... is therma blow in wool enough for melbourne area ? Final stage Re: I want to increase my Wall R rating without blowing $$$ 6Aug 14, 2009 11:39 pm d3p well, if my builder is going to use only foil wrap, definitely it's enough ! I wonder how they able to ads the rating as 5 star ? hm then i need to speak to my builder to put batts into the wall... i can sense there will be extra cost.... but if it's worth for it then so be it. about the ceiling, therma blow in wool. the inclusion seems to be reasonable good ? R3.5..... is therma blow in wool enough for melbourne area ? Wrap may be 'enough' for some silly government requirement but not enough for a Melbourne winter. Why don't you get some independent quotes for batts so you know you are not getting ripped off (you can't tell I'm cynical can you?) The recommended R values for different Australian climates can be found here: http://www.yourhome.gov.au/technical/fs47.html#levels What you use to achieve this doesn't matter a lot. Loose fill has the possibility of losing its effectiveness over time as it settles. Re: I want to increase my Wall R rating without blowing $$$ 7Aug 15, 2009 1:50 pm D3P. If you go with rockwool on all external walls + foil then that is your best choice. About 15% to 25% of heat is lost through your walls i winter in Vic. and the foil will stop the heat gain in summer. Walls are really hard and costly to do anything with after the fact, so spend the extra bit now and do it right once. R2.5 rockwool is 88mm thick - so fits in easily and you get around 75% reduction of the sound transmitted through the wall. If the budget won't stretch to rockwool, then glass is your next choice and R2 seems to be the max you can goto with glassfibre in a 90mm space. More info here http://www.bradfordinsulation.com.au/Products/Residential/Thermal-insulation/SoundScreen-Plus-for-external-walls.aspx The yourhome link shows minimum recommendations and personlly I'd be trying to get another R 0.5 higher above that. Which will also help you romp it in for the 5 star rating and maybe get you closer to a 6 star house. So I'd also ask the builder what R4 in the ceiling would cost - being blow in it's not hard to get a bit higher R value now for minimal cost I suggest. As for the $750 to do the HT - thats reasonable. R2.0 glassfibre would be $366. The R2.5 rockwool is around $1,341 That is if the 3 x walls each @ (4mx4.3m) = a total area of 51 m2. My Thoughts. Steve Re: I want to increase my Wall R rating without blowing $$$ 9Aug 15, 2009 11:26 pm dymonite69 Wrap may be 'enough' for some silly government requirement but not enough for a Melbourne winter. Why don't you get some independent quotes for batts so you know you are not getting ripped off (you can't tell I'm cynical can you?) thanks for the complete info.... melbourne wall 2.2 and ceiling 3.7 hehehe... i cant tell to be honest yeah, i have just asked my builder about it. he explained it actually compliant with 5star energy rating bla bla bla... at the end of the day, customer will suffer and worn the cost, if builder made mistake or false ads, just for silly gov requirement. Yak_Chat D3P. If you go with rockwool on all external walls + foil then that is your best choice. About 15% to 25% of heat is lost through your walls i winter in Vic. and the foil will stop the heat gain in summer. Walls are really hard and costly to do anything with after the fact, so spend the extra bit now and do it right once. R2.5 rockwool is 88mm thick - so fits in easily and you get around 75% reduction of the sound transmitted through the wall. If the budget won't stretch to rockwool, then glass is your next choice and R2 seems to be the max you can goto with glassfibre in a 90mm space. As for the $750 to do the HT - thats reasonable. R2.0 glassfibre would be $366. The R2.5 rockwool is around $1,341 That is if the 3 x walls each @ (4mx4.3m) = a total area of 51 m2. thx yakchat, oh i see.. so you can actually obtain R2.5 on 90 mm wall yeah ? sweet... i'll ask my builder to quote me on Rockwool for wall and ceiling R4 (is there any recommendation for what i should use to get R4?) seems glaswool and rockwool price has steep difference! i wonder how much they will be for 14x24 m house ? ummm how did you obtain 51m2 ? why is it only 3 walls, not sure why 3, when a room has 4 walls ? sorry, this is silly question, but i guess i have to ask hehehehehehe thx Final stage Re: I want to increase my Wall R rating without blowing $$$ 10Aug 15, 2009 11:50 pm How did I do the calcs - weell based on this. Quote: HT room, which is about 4 x 4.3m, for 3 sides Let me know the complete details ie area of all 4 walls and I can redo the calcs. Yes rockwool is expensive, so it's case of do you need the sound proofing? ie it not - then a downgrade to r2 for glass is your next option. But due to the density of glass at this thickness 90mm, it can only be r2. It's the old balance trick again. re r4 in the ceiling - they should be able to do that with the blown in stuff by going to a thicker amount, but as they typically rake it to the top of the joists the extra thickness can be a bit hit and miss unless they are a skilled operator. Re: I want to increase my Wall R rating without blowing $$$ 12Aug 16, 2009 10:59 am Sorry, don't know the installed cost of rockwool, but cellulouse is around the $1850 installed in a high pitch roof - Sound like it's time to ring some of your local suppliers of both these products to see what the local installed costs are. Re: I want to increase my Wall R rating without blowing $$$ 13Aug 17, 2009 11:28 pm thx yak chat umm.... not sure how 3 sides is calculated, i am guessing, because you need 3 batts to cover the whole wall ? dimension of the room is 4m x 4.3 m, so 2 sides of 4 m, 2 sides of 4.3 m. ceiling is 2.59 high. externall walls is 240mm, internal walls is 90mm. again, how do you calculate 3 ? thanks Yak_Chat How did I do the calcs - weell based on this. Quote: HT room, which is about 4 x 4.3m, for 3 sides Let me know the complete details ie area of all 4 walls and I can redo the calcs. Yes rockwool is expensive, so it's case of do you need the sound proofing? ie it not - then a downgrade to r2 for glass is your next option. But due to the density of glass at this thickness 90mm, it can only be r2. It's the old balance trick again. re r4 in the ceiling - they should be able to do that with the blown in stuff by going to a thicker amount, but as they typically rake it to the top of the joists the extra thickness can be a bit hit and miss unless they are a skilled operator. Final stage Re: I want to increase my Wall R rating without blowing $$$ 14Aug 18, 2009 2:11 pm d3p I don't know if your builder is saying wall wrap only ... you could read it as foil wrap + 1.5 batts (this would be a standard install). You would almost never get 5 star with wrap only and most builders wouldn't do it. Thus cost to go to r2 or 2.5 should be only a bit (although more to go with rockwool). As an alternative you could use foil board and r2 batts. This will be better than just wrap. I would not go for blow in. It degrades over time and makes it difficult to do stuff in the future. Just go with big batts properly installed. Make sure you have roof sarking as well. Re: I want to increase my Wall R rating without blowing $$$ 15Aug 18, 2009 10:40 pm hi lambchoppa hmm, yeah it seems a bit strange to have foil wrap only. i have confirmed with them, it's only foil wrap. they keep stating it's meeting gov requirement (i can sense it's not) ads below External Walls - R1.5 Foil wrap Ceiling - R3.5 therma blow in wool let's say, if it's foil wrap only, then surely i need to add for batts what everyone think about the ceiling? is R3.5 therma blow in wool enough? melbourne requires R3.7, so i guess R3.5 to R3.7 isn't that much? unless i missed something. if i opted for more blow, i am imagining it will be very thick in my ceiling, and become the possum "bed" lol Final stage Re: I want to increase my Wall R rating without blowing $$$ 16Aug 19, 2009 12:16 am D3P . How we mis things in text v words OK - that's what I needed Room is 4m x 4.3 m, 2 sides of 4 m, 2 sides of 4.3 m. ceiling is 2.59 high. Area - L x W x H x 4 walls of each dimension = 43m2 @ around $35 per M2 for rockwool - NOT installed. = around the $1,500 to do this room alone. Rough pricing only - builders price should be better. As for the builders saying that it meets govt specs !!!! Who gives %$#@%@(&*^ - if it just meet the govt specs.!!!! Do better and install at least R2 and foil now as a bare minimum - you'll appreciate it later. And enjoy your warmer less expensive to heat and quieter house from day one. Steve Re: I want to increase my Wall R rating without blowing $$$ 17Aug 19, 2009 9:34 pm Yak_Chat = around the $1,500 to do this room alone. Is that calc right or did you just say $1500 to do a single 4x4m room? What the hell would it cost to do the whole house? Re: I want to increase my Wall R rating without blowing $$$ 19Aug 22, 2009 8:46 am sweet thanks for the calculation yak chat it makes sense now ! those "x3" confuse me previously hmm to summarise.... okay so best option for me less $$, glasswool and reflective foil or best insulation, rockwool and reflective foil (more $$$) Yak_Chat D3P . How we mis things in text v words OK - that's what I needed Room is 4m x 4.3 m, 2 sides of 4 m, 2 sides of 4.3 m. ceiling is 2.59 high. Area - L x W x H x 4 walls of each dimension = 43m2 @ around $35 per M2 for rockwool - NOT installed. = around the $1,500 to do this room alone. Rough pricing only - builders price should be better. As for the builders saying that it meets govt specs !!!! Who gives %$#@%@(&*^ - if it just meet the govt specs.!!!! Do better and install at least R2 and foil now as a bare minimum - you'll appreciate it later. And enjoy your warmer less expensive to heat and quieter house from day one. Steve Final stage Re: I want to increase my Wall R rating without blowing $$$ 20Aug 22, 2009 12:08 pm Quote: hmm to summarise.... okay so best option for me less $$, glasswool and reflective foil or best insulation, rockwool and reflective foil (more $$$) More importantly - the sound absorbtion of rockwool is the key driver here. Rockwool has 0.5 higher r value for the same thickness - but a lot greater sound absorbtion and a significantly higher price. Hence most people tend to use it in certain areas only. The other option is to go thicker walls and get higher r value glass in there Even better - make it reverse brick veneer too - But I suspect that is not a choice you have via your builder at present. Just to makea point about this, an approach that some people have found sucessful in negotiating these rises down, Is to provide some workings to the builder, specifying… 4 81723 Fair Trading can issue orders to rectify and complete but once the matter goes to NCAT these orders are automatically vacated. You will have to terminate contract and sue… 21 29717 How are you doing Ben? Extremely interested in hearing what you are doing or plan to do! 12 15167 |