Topic: "NZ's first Passive House"

Re: "NZ's first Passive House" 

@ eurosceptics

the extruder has done the tests for durabbility here as it was always the greatest concern about uPVC.
They are obliged to manufacture the products accortding to the guidelines of the system provider.
And this system has been tested as such.

It is similar to the aluminium joiners who use a
system provided e.g. Fletcher and state in their producer statement that is made to their specs and meets relavant standards. The system has been tested at some stage but NOT the product of the individual fabricator who is responsuble that the product is up to the required performance stated in the documentation.

NZ is too small to operate test facilities which are able to perform window testing to an extend like the e.g. IFT in Germany does. There is much more testing involved than holding a hose and a fan against a sample wall with a window in it.

Re: "NZ's first Passive House" 

We need to define test for what kind of durability? As i've mentioned before, houses in NZ are constructed differently than overseas where climates are more extreme. This was one of the key faults in the leaky house syndrome. They took a cladding system from overseas assuming that moisture and climate would not be an issue here in NZ (ie. if it's that cold in Canada, then it must perform really well in NZ's climate).

Another words the reference to durability may only apply to methods where houses are built with active HVAC systems in place but never suitable for places like in NZ where passive heating methods, such as the sun, are more relied upon.

BRANZ today is more like a science - they're discovering what works and what doesn't. The reason why their work is accepted by city councils is unlike private companies, they're not likely to pack up and run away. There's no stopping an individual private company to dish out producer statements and in 20 years time, find out their product was a complete failure, then close up and hide in Australia.

The new LBP license scheme won't deter such an action but at least it will address the workmanship holding the tradesman at fault rather than the gov't getting exposed to the liability.

Re: "NZ's first Passive House" 

When I saw builders in the early 90's putting fibre cement sheets directly onto timber framing followed by thin plaster without any netting and the detailing, I asked them whether that is going to last ?
They smiled at me and said she will be right, thats how we do things here.
From that day I knew there is a problem here.
The way the leaky houses were built would have been even a bigger problem overseas especially in colder climates where the movement stress opens the joints is even bigger due to a large range of temperatures.
There is no such thing like a unique NZ climate and NZ building is not unique either.
Many places in the world are earthquakes, stormy weather, horizontal rain, severe heat and cold......
Timber framed house are build all around the world as well.
The problems are the shortcuts and must be flash looking but cheap building culture!!!!
Shortcuts are causing problems in various way where ever you build. Of course a poorly build house with leaks will last longer in climates with little rainfall.

Re: "NZ's first Passive House" 

SBQ- Re the Ecoply, I would imagine that the surface treatment (powder-coating or whatever) is to improve it's quality as a rain barrier allowing it to take weather during the building process and if the rain cavity was breached as well. It should be an air barrier but not a complete vapour barrier, I would have thought.

Re: "NZ's first Passive House" 

passivehouse: I don't disagree how the NZ building system is quite rigid in terms of accepting overseas methods or how there's a local ignorance that "she'll be right attitude". What happened was (and IMO the key oversight made in leaky house) is they didn't look at the 'whole system as a whole'. Instead they were looking at how to stop the humidity from forming inside the wall cavity by mainly looking at the outside elements while not factoring how much moisture occurs on the inside of the house (ie. bathrooms, kitchens, etc). As i've hinted before, the key distinctions between NZ houses and those in say Canada (I use Canada as an example having spending most of my life there) is that houses in NZ are pretty much passive in design. Whereas in Canada, houses are all centrally heated through the HVAC system that has humidity control etc. As an example, in Canada when I take a shower, the condensation on the windows doesn't stay for long as constant air circulation around the house rids it. When I take a shower in a typical NZ house during a cold winter, the condensation forms around the bathroom window and it stays there for a very long time (all morning or afternoon) - even the extractor fan isn't enough to rid it. Most people resort to leaving the window open when it's just above freezing point outside (how can you keep a house warm this way?).

So even though the timber framing may be similar, there's good reason why vapour barriers aren't used here. The building problems in the past were caused by not taking the full building systems used in cold climates - not in a way of taking short cuts.

I'll reiterate, even if you did take the full building concept say Canada's R2000 of air tight construction and mass insulation, what would the carbon foot print of that house compare to an already passively designed home we build today here in NZ? The running cost of the HVAC system would be considerable compared to the individual hot air heat pumps commonly installed today (used to heat 1 room at at time). One that uses it to heat maybe few hours a day vs. a full blown central heating system that is on 24hrs a day.

Re: "NZ's first Passive House" 

Lastman: Looking at CHH website they quote "The Ecoply Barrier system provides a weather tight rigid air barrier for drained and vented cavity systems outside the building frame effectively replacing traditional building wrap in the cavity while "

http://www.chhwoodproducts.co.nz/ecoply-barrier/

Air barrier sounds like to me - trying to stop air from moving in or out. BTW, moisture can not come about without a transport ie air movement to occur. This is the reason why inside spray foam does not hold any water because no air can get inside. But once you have air movement, then you have a carrier or moisture - plain and simple according to Mike Holmes.

But before I go further, we need to look at why this product is marketed this way. Virtually all houses in NZ don't have their exterior timber framing covered with sheeting. Basically what we have is the stud frame that is covered with Tyvek house wrap on the outside and on some corners of the framing, they may get a little bit of plywood. The rest of the strength is relied on GIB drywall bracing. So I assume with Eco-barrier, their method is to completely cover the whole exterior wall which is why they marketed as an air barrier.

But how does that compare to places like Canada that have always covered their wall framing with OSB or plywood? More importantly, this OSB/plywood covering isn't served as an air barrier because it's the vapour barrier lining that stops the outside air drafts from coming in. (it's the plastic lining that goes on the inside wall stud framing before the GIB goes up). Therefore, i'm still confused with the Eco-Barrier that if it replaces the Tyvek house wrap (which is a breathable membrane), does taping up the joins and the powder coating on the sheets stop moisture from passing through the walls? (future cause of leaky house?).

Re: "NZ's first Passive House" 

As a matter of interest. Local ITM retail price for 7mm Ecoply-Barrier 2440mm x 1200mm is $62.62 vs $33. for 7.5mm treated plywood. That's quite the price difference for a bit of tape and powder coating.

Re: "NZ's first Passive House" 

SBQ-"Air barrier sounds like to me - trying to stop air from moving in or out. BTW, moisture can not come about without a transport ie air movement to occur."

You seemed to be confusing air barrier and vapour barrier which are two different things. An air barrier prevents air born moisture transmission where as a vapour barrier prevents vapour diffusion through a wall like the polythene you are used to in Canada.

In the case of the Passive House. the Intello membrane is an air barrier and, supposedly, a one way vapour barrier which prevents vapour difusion outwards in winter but allows internal drying the other way, perhaps for requirements in summer.

Makes me wonder why they don't put the Intello on both sides, one way for summer and the other for winter ;-)

http://www.buildingscience.com/documents/reports/rr-0004-air-barriers-vs-vapor-barriers

Re: "NZ's first Passive House" 

The AIR BARRIER stops the external draft entering the wall and insulation which relies on still air to function fully.
Of course it also acts as a barrier to stop moisture being driven into the wall by the air.
The VAPOUR BARRIER stops or controls the penetration of internal moisture into the wall and insulation which also needs stay dry in order to function fully.

If the external draft comes as far as the vapour barrier or if there is none, the Gib, there is a serious defect in the air barrier or none at all.
In this case the insulation won't work very well.

Re: "NZ's first Passive House" 

.......I agree with Lastmanever, the Auckland Passive House does seem to be more "Massive" than "Passive". But in saying that I applaud the owner "applying" the Passivhaus standard to a piece of contemporary NZ Architecture. I am a certified PassivHaus Designer and we are building a simple 2 level 140m2 3 bedroom Passivhaus near Hamilton at present, which is a step-up in complexity from building in Auckland as Hamilton is around 41kKH/a verses 26 aprrox (higher the number colder the climate - generally). It has it pre-construction certification from PHI (Germany) and it should be all built in 3-4 months for under $2k/m2. There is no need to over complicate this........just pay good money for an experienced, and certified, designer and you will reap the benefits for decades.

Re: "NZ's first Passive House" 

Hi Eurosceptic
I understand you have to stand up for NZ be it write or wrong. However, I think Branz has proved it's capabilities, it has APPRAISED products and install methods stating in their opinion they are fine, which ultimately failed contributing to the problem with the leaky home syndrome.

Funny thing is NZ authorities still wants products to be appraised by BRANZ.

I guess that's the NZ way WE ARE ALWAYS BEST

YA RIGHT

Re: "NZ's first Passive House" 

"Guess What", I new you couldn't stay away.

Re: "NZ's first Passive House" 

I agree NZ may be too small to operate lots of test facilities, hence the INZA agreement, which allows other countries to carry out testing to NZ standards, but still the NZ Authorities will not accept them.

I wonder why?

As I said earlier New Zealanders think they are the best. Or could it be Fletcher's are so powerful.

Re: "NZ's first Passive House" 

I would put the blame at BRANZ for contributing the leaky house syndrome in NZ. It was a combination of many variables that caused houses to rot in NZ - 1 example is how the NZ Green Party had put through the ban of using treated timber framing in houses, in feer that the chemicals used created a high risk living environment. We can all agree that BRANZ has been wrong before but at least they try to put things right. BTW, the plaster finish methods for external cladding (ie EIFS) that was brought overseas to NZ came before BRANZ. If I stand corrected, the testing authority at the time (I think it was called BEAL / NZ Building Authority) was by the NZ gov't. They had approved such leaky house cladding methods and BRANZ was an aftermath of re-confirming the approval of such system. I would rather argue the conflict of interests building companies like Fletcher / CCH had with the NZ Gov't prior to the formation of BRANZ.

BRANZ isn't the only testing authority in NZ. The problem is for new products and methods to come to use in NZ, the process of appraisals is very costly. A minimum $15,000 which pretty much eliminates any extras that we see used in say N. America. A product say 'dimple membrane' that is fixed against the concrete footing of the house (to stop water from soaking into the concrete and to ensure the water goes to the drain tile) does not cost a lot make and the sales wouldn't be big enough in NZ as it's far cheaper to flick a paint of mul-seal. New housing constructions in NZ pretty much look the same having use of very few building material options. It's not that builders are trying to build at the lowest price but rather, the introduction of any non-standard material creates huge problems of getting code of compliance.

By international trade agreement, NZ is suppose to recognise overseas testing results. However, every city council has their own set of rules and interpretation of the NZ building code so that is where most ideas end. The onus is on to the builder to prove that the product used will work in NZ as a place like Canada will have a far more extreme climate than NZ.

I mean who could we blame for the cause of the leaky house syndrome? We've gone from 1 extreme to another. The agreement for those leaky home owners is 1/3rd cost to the local city gov't, 1/3rd to the federal gov't, & 1/3rd cost to the home owner. After what's happened, I don't blame any city council for not giving resource consent / building permit on a build that uses different materials and/or built on a different systems (for say air tight construction).