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Insulation options in 140mm timbre framing

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Insulation options in 140mm timbre framing

Posted 12 Aug '10 10:35 AM


I am at the point of specifying the insulation for my new home and have decided on a 90mm plastered brick/block veneer, 50mm cavity and then 140mm timbre framing and 10mm gib.

I have narrowed down the insulation options to;

1. Pink Ultra R2.8 wall batts @ 90mm 2. Latitude Wool R3.2 wall batts @ 140mm

Now according to the site these give almost identical R ratings for the entire wall.

Because the pink batts are only 90mm I end up with a 50mm cavity inside the walls and thus additional insulation - meaning it almost equals the full 140mm wool batts at R3.2.

Just wondering what the implications are of having that 50mm cavity in the walls? Will the batts move about? Is this a problem?

A positive I guess is there is 50mm of room for services etc on those external walls, and means there will be no gaps.

Just interested to hear if anyone has done anything similar or has any thoughts on this.

Thanks, Ben

Re: Insulation options in 140mm timbre framing

Posted 12 Aug '10 07:56 PM

Ben Autex Greenstuf is available in a 140mm R2.7 batt. It is a low density batt by comparison with their 90mm R2.6 which requires twice as much material as the 140mm batt to achieve its rating.

Try talking to Tom Gornall at Now Insulation ph (03) 381 1111. He supplies both the Autex and woollen insulation - can't remember which brand sorry.

I would steer clear of fibreglass. I went to a seminar recently where Johann Bernhardt - editor of A Deeper Shade of Green told us that glass fibres used in fibreglass batts take 20 years to leave your lungs.


Re: Insulation options in 140mm timbre framing

Posted 12 Aug '10 09:54 PM

Batts can sag when there is nothing supporting them from the sides, which means they will be mostly ineffective as insulation. I would suggest using batts that matches the thickness of the framing, or using the string support method (or an equivalent) as described on page 12 of this batt installation document:

Re: Insulation options in 140mm timbre framing

Posted 24 Feb '12 09:52 PM

have a look at they have a product specifically designed for 140mm wall cavity, R3.2

Re: Insulation options in 140mm timbre framing

Posted 26 Feb '12 08:06 PM

Not much different to pink batts really, and at least with pink Batts its a NZ company.

Knauf call their product Earthwool but is is glass fibre, that must me close to mis-representation of the product?

Re: Insulation options in 140mm timbre framing

Posted 26 Feb '12 09:13 PM

If the insulation sold by Knauf here is the same what they sell in Europe and made to comply with the relevant DIN/EN standards it is a far better product than pinkbatts. If it is an export version made just to meet NZ requirements it would be a different scenario.

Re: Insulation options in 140mm timbre framing

Posted 26 Feb '12 09:49 PM

From what I read the main difference is the formeldahyde content. At the end of the day its still glass insulation, not wool as the name implies. I see Right House are now using it as their insulation of choice, rather than Pink Batts.

Re: Insulation options in 140mm timbre framing

Posted 26 Feb '12 09:56 PM

Not quite sure why pinkbatts have higher formaldehyde? Do they ues outdated manufacturing methods or is it lack of know how?

Re: Insulation options in 140mm timbre framing

Posted 26 Feb '12 10:47 PM

Pink Batts is a hugely profitable business as their production costs are way below those of other companies.

I doubt that they would have any objective of reducing formaldehyde usage so long as they meet whatever regulations are in place.

Re: Insulation options in 140mm timbre framing

Posted 27 Feb '12 12:07 AM

The higher formaldehyde is surely not there because of regulation requires them to do so. Particle Board and MDF made in NZ has higher formaldehyde too compared to American or European Products. Maybe it has something to do with when their manufacturing equippment was updated last. Pinkbatts will put profit over peoples health for as long as the regulation allows them to do so or until the consumer stops using it.

Re: Insulation options in 140mm timbre framing

Posted 27 Feb '12 12:22 AM

Agree. What most consumers also don't realise is that the glass fibres that you breathe in during the installation process take 20 years to expel from your lungs. (This came from Johann Bernhardt, editor of a Deeper Shade of Green).

So many reasons not to use glass fibre, yet it is still the predominant means of insulation because it is well marketed and the cheapest.

Re: Insulation options in 140mm timbre framing

Posted 27 Feb '12 02:31 AM

What about all the pink batts sitting exposed in roofspaces which is separated from the living space by some loose lids only? We have lived in a rental once which had pink batts in the roof and the access through a loose lid in one bedroom and every time we had windy weather we had some shiny dust sitting everywhere. Surely that was was healthy ;-(

Re: Insulation options in 140mm timbre framing

Posted 27 Feb '12 02:45 AM

Though originally classified in 1988 as Group 2B (possible carcinogen) the International Agency for Research on Cancer (IARC) currently classifies glass wool insulation (all types) as Group 3 (not classifiable as to carcinogenicity in humans) and this was the same conclusion as the US National Academy of Sciences after reviews of studies since 1988 showed "inadequate evidence overall of any cancer risk". Reference:Healthy House Institute.

Certainly we've had a generation of people handle this type of insulation now without any quantifiable health detriment. I've heard various versions of the length of time fibres are supposed to stay in the lungs but also that fiberglass is biodegradable in the body.

I agree that it's a good thing to remove and reduce formaldehyde in the environment but it's also a very common substance and we are all exposed to it in various ways.

Re: Insulation options in 140mm timbre framing

Posted 27 Feb '12 02:45 AM

Another good marketing ploy from Pink Batts is the 80% recycled tag. Recycled from the waste Pink Batts that are thrown back in the hopper. Is there anyone that does the spray on foam application like they do in the US? Not the airfoam that they pump in walls but the one that is sprayed into new housing then they trim the overspray with a giant bread knife?

Re: Insulation options in 140mm timbre framing

Posted 27 Feb '12 04:38 AM

Re: Insulation options in 140mm timbre framing

Posted 27 Feb '12 05:43 AM

@ Lastman I have heard those results before - glass fibre manufacturers were pretty keen to get that around the industry as soon as the results came out but they were also keen to not spread the word about the length of time to expel the fibres.

Even if the time length in the body is half of the 20 years quoted I'd still choose differently if I knew beforehand for my own house. Still, only 17 years to go now.

Call me cynical but it just makes me think of a story I have heard from an industrial chemist who used to work for a large paint company in the US. There was a lot of pressure on them to develop a VOC free paint and there was one compound that they could not get the paint to work without, so the company managed to successfully lobby to get the compound `re-classified' so that it was no longer a VOC.

Re: Insulation options in 140mm timbre framing

Posted 27 Feb '12 07:19 AM

If you propose that organisations like the IARC and the US Academy of Sciences are just in the hands of big business then everything is a conspiracy and there's no point in having a discussion about anything.

As far as length of time in the lungs is concerned my understanding is that many foreign particles inhaled can stay in the lungs for long periods, even substances like cotton fibres and that's why protection should be worn in any dusty or high particulate situations.

I'm not trying to defend fiberglass batts per say but it just seems to me that some times products become unfashionable or get dumped on just because other people have their products to sell.

Re: Insulation options in 140mm timbre framing

Posted 27 Feb '12 07:48 AM

I'm not suggesting that there is anything wrong with those organisations, but I think you would find it hard to dispute that big businesses lobby legislators for more favourable regulations in all industries all over the world.

What I am saying is that we don't always hear about all of the potential issues with products. It's fine to say `This product doesn't cause cancer', but what about other potential issues? It would be nice to have a full understanding of what we are dealing with so that we can make informed choices about what we use.

Re: Insulation options in 140mm timber framing

Posted 03 Jun '14 09:44 AM

Pink Batts now offer a 140mm thick R4.0 wall batt.

The 50mm cavity you detail would have some insulation value if the air was still. If it is a sealed space, the stationary air would resist heat transfer, an air gap. This is the same way the batts work - lots of very small spaces, lots of air gaps that can't move about.

The newer wall batts are very stiff and likely won't settle over life-of-house timeframe.

Reports from the (now cancelled) mass home insulation in a hurry scheme in Australia indicate some imported Chinese insulation was incredibly high (20 times over limit) in formaldehyde. No doubt imported to fill the gap in local supply from such a large, rapid and poorly thought out scheme. This would suggest it's cheaper to make batts with high formaldehyde, which is likely Pink Batt's motivation as well. They will do what they can get away with. Knauf likely face more regulation in Germany and more informed consumer pressure to produce a safer product.

A now-dead-from-cancer friend of mine used to work in the Penrose Pink Batts factory. He said the innermost part of the manufacturing process, where the batts are actually formed is so toxic that no-one can go in there without a full body gas-proof positive pressure suit & airline fed respirator. Apparently a well guarded company secret.

Yes big scientific organisations are vulnerable to industry capture. The scientists & managers that belong to them have to work in the industry to have sufficient knowledge to be competent. They therefore have the vested interest or corporate pressure to dilute regulation. Add a right wing personality and you have the perfect opportunity to ensure ongoing profits at the expense of consumers & the environment.

Walk into a newly insulated house on Monday morning, closed up tight for the weekend, no wall linings on. The VOC from the pink batts is very obviously smelt. Catch the snag & snot in the back of your throat after an hour working in the space. Formaldehyde in action.


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