Browse Forums General Discussion 1 May 20, 2010 7:54 pm Hello guys. Thanks in advance to those who have gone to the effort of reading this thread and replying. My issue is as follows:
My building contract has a provision for wall insulation with a 2.5 R value rating. However my working drawings provide for wall insulation with a 1.5 R value rating as per 5 star minimum energy requirements. I queried this with my builder and they advised that the 2.5 R value rating provision in the building contract is a typo- that it should read 1.5. As such they have advised that I can choose to have the 1.5 R value batts and a credit of $810, or have 2.5 R value batts as per the building contract. My question to the forum is thus; would you choose the $810 credit or thicker insulation batts?? My considerations are as follows: 1. Does the $810 adequately compensate for the price difference between the 1.5 and 2.5 R value batts and also, 2. whether the difference in actual energy efficiency would be significant and, 3. if I choose to stick with 2.5 R value batts, should I insist the builder complete a new energy rating report as the current one is based on 1.5 R value wall insulation? Current rating is 6.2 stars. The house is roughly 11 metres by 19 metres. I have calculated the insulation coverage as 145² metres. The insulations batts used are CSR Bradford Gold Batts. I couldn’t find the RRP on the internet otherwise I could have done this calculation myself. Interestingly though, on the Bradford website, the wall batts range from 1.5 to2 R value and the ceiling batts range from 2.5 to 4.1 R value, so I guess if I chose to stick with the 2.5 R value batts, the builder would have to use the ceiling batts for the walls (does anybody know if there is a difference between the wall and ceiling batts apart from the R value??). Thanks a lot for all responses. Cheers, Michael Re: Builder's credit or thicker insulation?? What would you 3May 21, 2010 9:45 am no idea about the cost - I guess it depends on your circumstances and ask yourself if $800 is significant. If it isnt, then I would be leaning towards the insulation. If your counting your pennies, does $800 help much? Re: Builder's credit or thicker insulation?? What would you 4May 21, 2010 10:42 am Retail value difference between 1.5 and 2.5 wall batts is about $6 per m2. your price is pretty fair as no doubt orbit would be getting a better price anyway. There would be a slight but not great difference between them. Having 1.5 batts in the wall at all is enough however and I would suggest that you utilse the money as credits elsewhere in the home. "I never learned a thing until I finished school" - Unknown "You can get anything accomplished, If you don't mind who gets the credit" - Ned Hay Re: Builder's credit or thicker insulation?? What would you 6May 21, 2010 11:22 am If your roof insulation is I think R3.5 off the top of my head, then adding R2.5 to your wall cavity will take your house to a 6 / 7 star rating which relates in round terms to about a 25% or greater reduction in cooling and heating requirements. Re: Builder's credit or thicker insulation?? What would you 7May 21, 2010 1:25 pm Thanks guys for all your responses. I have had some developments since my original post. Apparently it is not possible to have 2.5 R value rating wall insulation batts because they are 14cm thick and the frame is only 9cm thick! The foil insulation is stapled to the frame so you wouldn’t be able to push the 14cm thick 2.5 R value batts into the external wall frame! I wonder what my builder is playing at by even giving this to me as an option?? As an aside, the 1.5 R value batts are 7.5cm thick and there is a 2 R value batt with 9cm thickness.
I spoke with a Bradford rep today who told me that the 2.5 R value batts are RRP $92 a bag and the 1.5 R value batts are RRP $61 a bag. Both bags give 12.2 meters² coverage so considering my 145 meters ² coverage area, that would work out to about 12 bags. The RRP cost difference therefore is $373- much less than the $810 my builder is offering me! kid81- can you please reply about the $6 per meter difference you quote- is that correct because it does more accurately reflect the amount of credit my builder is offering me? I also spoke with a First Rate energy accreditor and he told me that the difference in energy efficiency would be marginal- about .2 to .3 of a star. So I guess that would push my rating from 6.2 stars to about 6.5 stars. He also said that if I chose to go with the thicker batts that I wouldn’t need to get my energy rating reassessed- that a reassessment is potentially required when downgrading specifications, not upgrading. Huggy_B, my roof insulation is 2.5 R value rated. I think I will take the $810 credit instead of the 2.5 R value batts (if even possible to have those)! It looks like the energy savings would be marginal and from what I calculated, I am generously compensated for the price difference. If the energy efficiency made a big difference I would have chosen otherwise. Thanks guys! Re: Builder's credit or thicker insulation?? What would you 8May 21, 2010 3:36 pm There is an R2.5 insulation batt available for a 90 stud wall. I take it that you are in a 'warm' climate when you say R1.5 is ok under reg's & are you sure it's not at min. R3.5 in the ceiling. 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: Builder's credit or thicker insulation?? What would you 9May 21, 2010 3:49 pm Hmmm... thanks for the post Peter. That gives me something to think about. I have left a message with my builder to confirm R2.5 for the external walls is do-able. I’m in Melbourne, Victoria so I wouldn’t say it’s a ‘warm climate’. I’m pretty sure the minimum 5 star energy requirements here are R1.5 batts + insulation foil for the external walls and R2.5 batts for the ceiling. If you know any differently then please let me know!! Also, you seem knowledgeable so could you please post if you would take the credit or better insulation?? I think I’ll give myself the weekend to make my mind up and let the builder know on Monday... Cheers, Michael Re: Builder's credit or thicker insulation?? What would you 10May 21, 2010 4:19 pm Melbourne is generally 'climate zone' 6 which on a brick veneer home requires under the BCA a minimum of added wall insulation of R1.65. The industry 'standard' for southern areas of Vic is now R2.0 wall insulation plus RFL facing the cavity. In theory R1.5 batts + RFL will achieve greater than the 1.65 ( around R2.0 ) I would myself look at R2.5 or failing that R2.0 at minimum. Wall insulation is not accessable so once the decisions made thats it. When Vic moves to a min. of 6 stars next year I envisage R2.5 will be the norm. R3.5 ceiling is minimum 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: Builder's credit or thicker insulation?? What would you 11May 21, 2010 4:41 pm I am a CSR distributor in WA and I can tell you that you can get R2.5 for 90mm stud walls and its called SoundScreen Plus. And it has the added benifit of being very good acoustically. There isn't much call for it here in WA given our double brick construction, but I've been told they use it a bit on the east coast. I couldn't tell you what it costs offhand. Re: Builder's credit or thicker insulation?? What would you 12May 21, 2010 4:51 pm You Sandgropers love your bricks ! Whats the standard for cavity insulation ? Foilboard or something similar ? 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: Builder's credit or thicker insulation?? What would you 13May 21, 2010 4:52 pm When the home is energy rated, the wall requirement would vary.That said, wall wrap and 1.5 wall batts would exceed current requirements. From a cost saving point of view, it is not going to be a huge difference between 2.0 or even 2.5 walls compared to 1.5 as you have seen with the credit offered. Your energy bills will not vary much when you compare 1.5 to 2.0 or 2.5 wall batts. the significance in those savings is ussually seen when comparing no batts at all to having wall batts. Also, from a comfort point of view, you will not notice 1.5 compared to 2.5 very much if at all. It is more for Accoustic purposes than anything else. Feel free send me a message with any question you have or post it here and i will endeavour to reply in regards to pricing, size, availability etc as soon as i can. Builders (I work for a very large one) work on m2 rates in most cases. I know that the difference in price between 1.5 and 2.5 can be between $4 and $8 a m2 depending on brand used and buying power of the builder. As Orbit is a medium size builder, I can estimate that the difference would be around $6 m2. I could of course be way off and the sums could be a coincidence as there are a few different methods of calculating cost. If i were you however, I would be satisfied with the credit offered and utilise it on a Jetmaster. Not for heat but for asthetics and red wine consumption in Winter "I never learned a thing until I finished school" - Unknown "You can get anything accomplished, If you don't mind who gets the credit" - Ned Hay Re: Builder's credit or thicker insulation?? What would you 14May 21, 2010 5:20 pm Just a quick one before I get the firewood in - there is a difference between melb. & perth as to 5 star levels. Don't hold me to it until i've got time to check but melb. figures are around 150mj /m2 against perths at 90mj/m2. If thats correct then the insulation comparisons need studying as to benefits 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: Builder's credit or thicker insulation?? What would you 15May 21, 2010 6:52 pm You got all your answers already, but here's my 2 cents. Basically there are 2 main factors for me - the local climate (location) and your plans with the house. So, the location first - where is the house (lucky you added this info later on). Sydney gets very cold, but Melbourne is even colder, and during a longer period overall. Secondly, are you going to live there for a while? If yes, I would personally prefer to feel a bit more comfortable without having to turn on/off the a/c too much. I believe that there must be some noticeable value in a higher R (noticeable to a human, not just some thermometers or energy calculations - don't really care about those if my body can't detect a more pleasant environment without mechanical help like a/c or heaters or whatever). Speaking of Rs, I think that 1.5 is way too low for Melb. We upgraded our wall from 1.5 to 2 - should have went for higher, just didn't think of it at the time! You might also have wall wrap, so this adds some R as well. Still not enough for Melb IMHO. Speaking of credit, I thought it was more than really really good Overall, I would go for highest spec possible. Same for roof (but, you will have access to roof area later on, so you can add to the roof yourself if you think it's required). My signature is distracting people from my wise posts ... Re: Builder's credit or thicker insulation?? What would you 16May 21, 2010 7:42 pm Thanks ausdesign, Huggy_B, kid81 and Lex. I appreciate all your responses. Well I have spoken with the builder and they have confirmed that they would indeed need to use the CSR Bradford Soundscreen Plus R2.5 batts. I guess initially I was leaning towards sticking with the R2.5 batts because I had the impression they would bring significant energy savings in the long run over the R1.5 batts. Then after realising any additional energy efficiency would be marginal I was leaning towards taking the $810 credit. However, now that I know the batts specifically provide significant accoustic insulation I am leaning towards taking them again (my head is spinning haha!) I am building in a new residential development where the lots are so small you are basically seeing into your neighbour’s lounge room from your kitchen- in these circumstances I think accoustic insulation is a very important factor. I guess now that we have established that the R2.5 batts are the superior CSR Bradford Soundscreen High Performance product, do you still think the $810 is fair compensation to stick with the regular CSR Bradford 1.5 Gold batts?? It is hard to keep the $810 credit in perspective. In a $200,000 building contract it is not much, but on its own I don’t think that many people would scoff at that amount. If I had to pay an additional $810 to have this product I wouldn’t. However, seeing as I don’t have to pay anything more for it I am tempted to leave the equity in the house. Also ausdesign, I am really concerned that you say the minimum requirement for ceiling batt insulation is R3.5 because my building contract and working drawings definitely provide only for R2.5 batts. You say this is a requirement under the BCA but I’m not familiar with these regulations (is it Building Codes Australia???). My house was ‘FirstRate house energy rated’ on 09/02/10 as you can see scanned below from my working drawings- and here it says the minimum requirement is R2.5. Has the requirement changed since that date?? I guess my concern now is that my house does not meet minimum standards. I am getting my builder to follow up this line of enquiry as well. Oh, if it helps, I am building in Tarneit. Thanks guys, have a good weekend! Re: Builder's credit or thicker insulation?? What would you 18May 21, 2010 10:17 pm Looks like by some lucky admin mistake you got this upgrade for free. You were not expecting it and definitely the 810 neither. I would take the batts (money can be replaced later, but better wall isolation not without some considerable mess ) ... My signature is distracting people from my wise posts ... Re: Builder's credit or thicker insulation?? What would you 19May 21, 2010 10:57 pm Confusing isn't it. ! The BCA - Building Code of Aus - part 3.12 stipulates minimum thermal requirements for the envelope of the home under the 'Deemed to Satisfy' clauses of the legislation. There are further requirements in regards to glazing, subfloor insulation, skylights etc etc. Within the 'Deemed to Satisfy' requirements for climate zone 6 (tarneit) there are variations depending upon the construction type i.e. weatherboard clad, brick veneer, solid brick etc The minimum total R value required for roofs is R3.7 Walls a minimum total R vaue of R2.2 . . . and it goes on with subfloor insulation, glazing levels, skylights, etc For a brick veneer home the 'added' wall insulation to achieve R2.2 would be R1.68 For a weatherboard home it would be R1.73 For a typical (there are variations for ventilated or unventilated roof spaces) tile or iron roof the added insulation required would be from 3.3 to 3.5. Above all this, a 'thermal energy assessment' (energy rating) which is an option to complying with the 'deemed to satisfy' regs - & which most go for because it is 'simpler' can overturn all these figures, which some knowledgable body has determined, because the rating calculates & gives a finding on the efficiency of the overall envelope. An absurd example, but with a rating I might be able to nominate R2 to the ceiling & R4 to the walls or R4 to the ceiling & R2 to the walls & come to a similair result in the overall points score. - I don't think thats a good example, but you can get the gist. At the end of the day I will not design a home with less than R2.0 to the walls, R3.5 to the ceiling (R4.0 preferably - above this the payback value is too great at todays prices) If not a concrete slab then R1.5 minimum to the subfloor. There are a heap more variables that come into play such as orientation, overshadowing from neighbouring dwellings . . & it goes on. Just to push the AusDesign barrow . . We were the first design in Vic to receive the then 5 Star rating for energy efficiency, way back in around 1984 (different to todays rating) Having followed this path since then with all our design work I am encouraged by todays legislative requirements. 6 Stars next year in Vic will be good. Got off the track there. PM me if you want any further info. 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: Builder's credit or thicker insulation?? What would you 20May 22, 2010 12:44 pm Thanks for the comprehensive information ausdesign. It’s good to hear your company are strong advocates of energy efficient design. So technically I’m compliant with regulations even though my ceiling batts are R2.5 rated. OK, just one last question- if I choose to put in R3.5 batts in the ceiling at a later stage can I lay them over the existing R2.5 batts or should I remove them? I’m thinking here that the more the better but I wonder if I pile them up so thick that maybe efficiency is somehow compromised if the batts are not actually laid within the ceiling framework if you get what I mean. I have access to excess stock of R3.5 batts so this exercise would not cost me anything other than my time. At this stage I will forgo the credit and stick with the better insulation I think. Thanks guys. Bought in Nov 21 at the height of the market (classic). Good area, atrocious floor plan. BUT has land out to the left-hand side that we can extend out on (see second… 0 8902 Thanks mate. Yeah good points! Leaning towards Option 3 to get a bit extra space in the cabinets but not going too crazy high (and expensive). 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