# Forum Home Renovation Heating & Cooling  What Type of ceiling insulation? R value, material etc

## DaleBlack

Hi 
I currently have broken down dusty insulation like in the photos in this link  Kings Energy Saving Services - Home Insulation Perth, Energy saving Perth, Skylights Perth, Insulation batts Perth, Roller shutters Perth, Downlight guards Perth. 
Once its gone, I need to put new I assume batts in. 
It also needs to come out due to carpet beetle possible infestation. 
What is the temperature saving in a hot 40C summer of R3.5 vs R4 or R5. 
Locale Perth 
Can anyone recommend materials glass/fibre, polyester, wool? Do some resist pests like carpet beetle better? 
Also should I go for foil sarking under the tiles as well as batts on the ceiling?

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## The Roofer

Hi Dale
This all depends on the following what total R Value you achieve:
1.  Is the roof metal or tile?
2.  Has the roof itself got insulation blanket?
3.  Is the roof space ventilated or not?
4.  Is the ceiling 10mm plasterboard?
All these add up in the R-value - Perth is in Zone 5 and has a minimum requirement of R3.2 so in reality you can just go for anything over this in the R-Value of the batt and the results will be good. The higher the better - but a lot also depends on wall insulation, position of the house and windows etc.

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## DaleBlack

Hi see below 
This all depends on the following what total R Value you achieve: 
1.  Is the roof metal or tile? Concrete Tile house early 80s
2.  Has the roof itself got insulation blanket? No just the raw tiles
3.  Is the roof space ventilated or not? by way of whirly birds? no but I would normally put some in. What effect does this have.
4.  Is the ceiling 10mm plasterboard? Can not answer that one 
All these add up in the R-value - Perth is in Zone 5 and has a minimum  requirement of R3.2 so in reality you can just go for anything over this  in the R-Value of the batt and the results will be good. The higher the  better - but a lot also depends on wall insulation, position of the  house and windows etc. 
One guy I rang today was adament R3.5 is fine and that R4 or higher will see hardly any benefit in say dropping the house temp a few degrees more in a 40C summer. What do you think about this? He recommended Knauf (usa) batts over pink or bradford. 
Also fibreglass or poly?

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## The Roofer

Dale, 
Below are the calculations for your ceiling: 
The ventilation is important as the results are different in summer compared to winter. Ventilation can be whirlybirds, under eaves vents or dormers etc. What they do in summer is allow the heat buildup to escape - but in winter you need the heat retained (thats why open/shut type ventilation is the best).
As you can see - with R3.5 Batts your total R-Value is above what Perth requires - but saying there is no benifit in going to R4 is not correct - as you increase the R value - the insulation becomes more effective for longer - especially if you are running Air Cons - you will save in power by going higher. Insulation does not drop the temperature - it stops it rising as rapidly if there was no or less insulation. There's a good section in the Bradford website CSR Bradford Insulation on this. 
On the question which is a  

> better product Knauf, Bradford, Fletcher, Pink etc

  - If a batt is rated to Australian Standards as R3.5 - then the performance is exactly the same regardless of brand. I would look at costs and also if you are allergic to any of the products. You can also the wool batts.  
Ask the guy to work out the total R value of you roof space with R4 and R3.5 - the answers are as follows (with foil):
                    Ventilated       Non Ventilated
Summer        5.2                     4.9
Winter           4.4                     4.6 
You should have some sort of foil directly under the tiles also? Helps prevent moisture from dripping onto the ceiling.

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## DaleBlack

Hi , thank you for the table. 
What do you think of the Knauf, Earthwool brand? has been recommended a couple of times now to me over Bradford and pink.

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## The Roofer

Hi Dale
I haven't used the Knauf Earthwood brand - but are very popular - if you're doing it yourself - wool is kinder on the skin than glasswool batts. Once it's in the ceiling you won't see it. Also Moondog gave a good link in another post on insulation Your Home Technical Manual that has the comparisons between the different products. But remember R3.5 is R3.5 regardless of type or brand!

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## PhilT2

Knauf earthwool is still glasswool as far as I know, less irritating than some but still likely to affect those who are sensitive to glasswool.
I had a look at the site you linked to that shows what you have, but it is difficult to tell from the photo. Are you sure that what you have is wool? Looks a little like cellulose to me but hard to tell. Cellulose can be very dusty even when new. Not an expert on carpet beetle but I think they would only be present in wool, not glasswool or cellulose.

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## Smurf

If you're going with glasswool (fibreglass) then the Pink Batts and Bradford both are a quality product in my experience. 
Personally, I'd buy the locally made product simply for reasons of (1) employing Australians and (2) avoiding buying yet another product that has been shipped half way around the world (using quite a bit of oil to do so...). If we can't even make our own basic building materials in this country then that's a real worry in my opinion - if the quality is good and the price is OK then I prefer to support Aussie industry where I can. 
If you're going for wool or polyester then again, there are local manufacturers and I've not heard of any problems with their products (beyond issues which are generic to all products using certain materials).

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## The Roofer

Smurf   

> I'd buy the locally made product

   :Exactly:  - we all should keep this in mind when recomending products  :Aus:

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## DaleBlack

Hi all thanks for the comments. 
Re carpet beetle - i do believe they can only eat in organic material so your right, assuming they definately are up in the ceiling as well (not known) - it would have to be wool. 
The link provided shows Perth as needing R4.1? so maybe I should aim for that not R3.5.

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## The Roofer

Hi Dale, 
Sorry, late reply
Yes - Perth is R4.1 - I wrongly used old data. Also the batt manufacturers should be able to tell you if thier product is resistant to carpet beetles.

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