What insulation upgrades should I prioritise?

[Samara1]

First time building two storey in Sydney. I love to do all the below insulation upgrades, but due to budget limit which one i can give more priority from the below list. kindly advise so i can plan accordingly.

[MitchellMc · Accepted solution]

Hi @Samara1,

To clarify, are these costs for upgraded insulation from what is currently specified, or is there no insulation and these are the prices to install it? 1) and 2) appear to be insulation in areas where there is currently none planned, and 3) and 4) appear to be upgrade costs of the already planned insulation.

Out of the list, I would prioritise 3) and 4) as insulation in the external walls and ceiling is important to stop heat transfer into the internal spaces. 1) and 2) help insulate the top floor from the bottom and individual rooms. These are of lesser importance but still will help isolate areas, leading to more efficient heating and cooling of the spaces. Being acoustic insulation, they also assist with noise transfer between rooms and floors. 

If you've already paid for insulation in the external walls (R2.0) and ceiling (R3.5), which are the requirements, it could be worth leaving them as they are and adding insulation in the underfloor ceiling and internal walls, where there is currently none. That way, you'd have an entirely insulated house.

The question is whether you want to invest in upgrading to thicker insulation in the important areas or sticking with the basic requirement and investing in other, less important areas with no insulation. You're not getting a huge upgrade in the external walls R2.0 to R2.5, but the ceiling is quite substantial R3.5 to R6.0.

It's a bit hard to tell you what would be best. I'd encourage you to try and do 1), 2) and 4). 4) would make a substantial difference in preventing heat transfer from the roof cavity into the upper level. 

Please let me know if you have any questions.

Mitchell

[Samara1]

Great thanks @MitchellMc well explained.

you are correct on the points 1 (underfloor insulation) & 2 (Internal walls) are new additions and both are HD acoustic insulations.

3) External wall upgrade from R2.0 to R2.5 acoustic insulation & 4) ceiling upgrade from R3.5 to R6

[Samara1]

2 storey home under construction. In GF ceiling, every alternate ones are not covered (marked in image below) with joist packers but the garage one is fully covered. Now the brick is laid outside without any wrapping in this area.

I am planning to do insulation between floor level, so if this is not covered then will the insulation be exposed to wet weather and airtightness not possible achieve here?  do I need to ask my builder or insulation guy to cover this open areas before insulation? If they don’t, then anything I can do to cover this area. I don’t know what principle behind this. kindly advise.

[MitchellMc]

Hi Samara,

I touched on this briefly in your other discussion, but homeowners are typically discouraged or, in some cases, not allowed to enter the construction site until it is handed back over to the owner. Part of the reason is that we are not builders, so many aspects of the build might seem confusing. As with this situation, it could just be that there are only requirements for every second void to be covered.

I can't imagine that because there are no spacers between the joists, the area would be left exposed to the weather. If you have concerns, it would be worth speaking to the builder or enlisting the services of a private certifier to alleviate them and answer your questions about the build.

Insulated areas don't always need to be air-tight; in some cases, it can lead to condensation build-up and moist environments. 

Please let me know if you have any questions.

Mitchell

[Samara1]

thanks @MitchellMc  i am building with local custom small builder so he allows me in site during construction and i asked him to fill this gaps but he said its standard and dont want to fill it up. but i want to know experts opinion whether this is standard and what will happen if this gaps are not filled. 

[MitchellMc]

The builder is the expert @Samara1. If you wanted someone to assess the work to determine whether what the builder has done is adequate, that would be a private certifier. You can enlist their services, and they'll review your entire build and provide a report on whether items like not filling these gaps are adequate and compliant with building codes. 

Unfortunately, from your description, we can't determine whether this is standard or what will happen if the gaps are not filled. We just need to trust that the builder is working to building codes. If there's a reason to believe they are not, you'll need to enlist a private certifier's services to look at their work. Unlike typical D.I.Y. enthusiasts, private certifiers are very familiar with the thousands of building codes that must be followed and can easily pick out when things are not to standard.

MItchell

[Samara1]

@MitchellMc 

i want to avoid noise at the max, by adding acoustic insulation between floors and internal walls.
also i need to decide between these two options for undefloor ceiling, first one is 32kg and second is 20kg: here thickness does not matter between R2.7 (90mm) and R4.0 (140mm), only the density? both are HD suitable for acoustic right, then how R4.0 weights less but more R value. R4.0 (140mm) HD gives the same acoustic (same) but more thermal than R2.7 HD here? price diff between this two is $275

which one to go for here. 

1) Supply & install R2.7 (90mm) High Density Acoustic (32kg/m3) insulation to underfloor ceiling area (including garage area)
ADDITIONAL PRICE – $1,975.00 + GST.

2) Supply & install R4.0 (140mm) High Density Acoustic (20kg/m3) insulation to underfloor ceiling area (including garage area)
ADDITIONAL PRICE – $2,250.00 + GST.

[EricL]

Hello @Samara1 

If the insulation provides the same level of noise insulation, but the more expensive one has a better "R" rating, then that's what I would recommend getting. On the condition that it fits your budget, getting the more efficient insulation would be the smart investment.

If you need further assistance, please let me know.

Eric