Leaky Homes Exposed 

Who Are BRANZ And What Do They Do?

The Building Research Association of New Zealand (BRANZ), traces its roots back to the 1950’s 'Building Research Bureau' and has been continuously and intimately involved in all of the changes to our framing timber and cladding systems which resulted in what we now call ‘leaky buildings’. 

BRANZ is a pseudo Governmental Organisation supporting the Building Industry. Its charter is to be New Zealand's 'independent research organisation' and is funded by a levy from every building consent, as well as commercial activities such as Appraisals and book sales.

BRANZ created an ‘Appraisal System’ as early as 1970. So how does this work?  Surely there is a conflict of interests?

On one hand, BRANZ is funded by homeowners to provide independent research and advice on how to build their houses.  On the other hand,  the sellers of some of those products pay BRANZ to Appraise and promote their products to the organisations designing, approving and building those homes.  Surely this is the ‘Gate Keeper becoming the Poacher’.  Whatever way you look at it BRANZ cannot be seen to be independent when they get paid by both parties. 

In fact, the BRANZ document “Appraisal Certificate Annual Validity” promised that “BRANZ Appraisals will continually support the commercial success of all products with valid Appraisal Certificates, i.e. those who continue to stump up the money, continue to have a BRANZ Appraisal and get BRANZ support for their products.  

The Councils and the MBIE (formerly Building Industry Authority) rely heavily on these Appraisals for guidance on whether products and systems will meet the requirements of the Building Code and can be used in a building.

Should BRANZ be Accountable?

“A BRANZ Appraisal is a robust, in-depth and independent evaluation of a building product or system to assess whether it is fit for purpose and meets Building Code performance requirements.” - BRANZ website.

That sounds impressive!  What do the words robust, in-depth and independent mean to you?  

• Should they take into account their own internal research and testing? 
• Should they consider the New Zealand Standards and understand what the Building Code says? 
• Should they require proof, or carry out their own testing to make sure that the Building Code requirements will be met?

And, when they certify unproven, defective products and systems, should they be held to account, and made to contribute to the losses suffered as a result?  The councils certainly thought so when they tried to join them into various weathertightness court cases.

Let’s just consider one of the Appraisals that led to the Leaky Homes disaster. And remember when we say that BRANZ Appraised something, you can take that as meaning that they approved of its use and were saying that it would meet the requirements of the Building Code.  In the case of framing timber, this was for the life of the building or a minimum of fifty years.

BRANZ Appraisal 279A Timeframe - H1 and Treatment-Free Timber

In 1998, BRANZ issued BRANZ Appraisal Certificate 279A.

Note the “SPECIFY WITH CONFIDENCE” Tag

BRANZ Appraisal 279A included Origins Timeframe Untreated Kiln Dried Timber (UTKD, which then decayed, sometimes within months and even sometimes before the building was completed. 

However, BRANZ “robust, in-depth and independent evaluation” concluded that:

From BRANZ Appraisal Certificate 279A, Page 3.

And what tests did they carry out to come to this conclusion? 

What? No tests on durability?  So how did they decide that undertreated (H1) or untreated timber would last at least 50 years in the intended applications without tests?

That sounds good. They obviously researched the performance history of untreated radiata pine in NZ houses and were satisfied that treatment wasn't required.

 But hang on.  The 1952 Boron enquiry was set up because untreated radiata pine was being attacked by borer and decaying.  The Forest Research Institute conducted thousands of tests to find a solution and the Enquiry determined that boron at an average of 1.2% BAE (boric acid equivalent) was required for controlling all wood-destroying pests.  

The Boron enquiry was so concerned that homeowners might suffer loss from untreated timber that they wrote:

Paragraph 102: "The Committee regards as necessary the provision of a penalty for selling as “treated” timber, timber which is in fact untreated or insufficiently treated, on account of the irreparable damage that may be suffered by an innocent purchaser in such case."

Maybe the radiata pine we grow now is better than the pine they grew in the 1950's?  Actually no, the plantation-grown pine we use now is actually softer, mainly sapwood and less durable.  Or maybe they looked at Carter's report on 50-year-old railway cottages in Ranui - but with radiata pine heartwood, with eaves and no internal linings and considered they were comparable to a modern Mediterranean style house with no eaves, flat roofs, fully lined and built with soft sapwood?

BRANZ - we would love to see your assessment of the performance history that led you to Appraise H1 timber (treated to protect against insects only) in 1994, then decide in 1998 that absolutely no treatment was required.  

Obviously, they thought they knew more than the Forest Research Institute however, the Leaky Homes Scandal is absolute proof that their assessment was defective.  It's hard to believe that they were acting as an independent assessor when they put so many homes at risk.  Was there some commercial pressure from the large timber suppliers?

And what limits did BRANZ put on the use of these products? 

So the BRANZ Certificate required that the moisture level needed to stay below 20% for the life of the building.  That sounds reasonable, but what does it actually mean for the council, the builder and the homeowner?

No construction moisture trapped in the walls, no leaks, no defects, no moisture migration through the walls, 100% maintenance of all sealants, no window failures, no leaking internal pipes, decks or showers.  If all this was guaranteed, then the timber should last 50 years. 

That is not practical or achievable in the field as BRANZ own testing in 1986 had already shown (see below).  In 2002, when they finally tested the cladding systems they had Appraised for use over this timber years earlier - they all leaked. 

And where did the figure of 20% even come from?  Table 1D of NZS 3602:1995 allows the use of untreated timber where the in-situ moisture level is 18% or under. For H1 timber, it had to be under 24%?  The 20% figure appears to be an arbitrary in-between 'Hi and UTKD' figure.  Where is the research to justify departure from the standard?

And, if the timber is hidden behind cladding and gib, how can anyone measure the moisture to make sure it isn’t more than 20%.  If the timber must be kept below 20%, but this is almost impossible to achieve, and impossible to measure without installing a full moisture probe system, surely the Appraisal is next to useless?

How can you Appraise a product as fit for purpose when the conditions placed on its use can’t be met and can’t be verified.  Obviously, you shouldn’t. This product should never have been Appraised without exceptionally strict restrictions on where it can be used.

However, with this BRANZ Appraisal, anyone could now “Specify Untreated Timber With Confidence”.  Other timber manufacturers had their untreated timber Appraised as well and before long this became the timber of choice.  

The Councils were also negligent by accepting this Appraisal as support for Alternative Solutions without insisting on construction methods (e.g. decent flashings and drained cavities) to manage moisture and a way of monitoring the building to ensure the timber stayed below 18%.

BRANZ Prior Research 

In 1994, BRANZ surveyed thirty-year old stucco homes and found serious structural damage due to decay.  These would have had boron treatment to 1.2% BAE i.e. about 3 x the current H1.2 treatment. They reported this in their Good Stucco Guide 1994. Although they didn't go into details, the decay was likely caused by leaks or other defects that eventually leached out enough boron until it couldn’t stop the decay. This is what happens with boron – its effectiveness decreases with long term leaks so a high level of treatment is required if the timber might become wet at some stage.  

If even well-treated timber decayed behind stucco, how could they then appraise undertreated and untreated timber for the same use? 

In 1986 BRANZ carried out weathertightness testing on aluminium windows and all of them leaked, even those fitted with full sill trays.  So, if all windows leak, how could they appraise a product that required no leaks?

This is the summary table from the report.

In 1983, BRANZ research scientist (Cunningham - BRANZ Report rp076), published work on how walls dry out and determined that walls with face-fixed cladding dried out extremely slowly, if at all, in NZ conditions.  In fact, due to the condensing that takes place during winter, wall cavities could even get wetter and wetter.  

“Furthermore, conditions are often such that more moisture condenses into the cavity during winter than evaporates out of it, giving rise to a net accumulation of moisture into the cavity during this winter wet-up period. If conditions are this severe, the possibility exists of more moisture accumulating each winter than dries out in the following summer; leading to serious moisture problems, occupant discomfort, and possibly even irreversible structural damage”

“Irreversible structural damage” - due to decay - and this was with walls built with very well treated C8 grade timber.  

Cunningham concluded that “Under no circumstances should very wet timber be enclosed into a cavity ”

Note that this report was never published in NZ but can be found in the BRANZ library.

The BRANZ Certificate made no mention that face-fixed claddings, like Harditex, Hardibacker, Insulclad etc would keep timber wet for longer, and that H1 or UTKD timber shouldn't be used under any circumstances behind them. 

Instead, all of these products were appraised as acceptable without restriction, and the industry and the councils quite reasonably took this to mean that they were fit for purpose.

Even when it became clear that BRANZ Appraisal 279A was flawed, BRANZ never withdrew it - that could have been seen as an admission that it was defective, which could have led to claims of liability.  Instead, it was just allowed to lapse.

Conclusions

BRANZ promoted themselves as the experts and that a BRANZ Appraisal allowed products to be “Specified with Confidence”. 

BRANZ were paid by manufacturers and importers to Appraise their products.

BRANZ were also paid by homeowners to provide independent research and advice on suitable building products and systems.

Architects, designers and builders specified, bought and built with BRANZ Appraised products believing that they were fit for purpose.

The BIA and the Councils relied heavily on BRANZ Appraisals for Acceptable Solution, Alternative Solutions, approving Building Consents and inspecting construction work.

BRANZ had carried out testing showing that all aluminium windows leaked.

BRANZ research in 1983 showed that construction moisture in enclosed framing (face fixed claddings) would take many years to dry out (if it every dried at all).

BRANZ Appraised H1 and Treatment Free Timber would meet the requirements of the building code for framing timber provided it remained under 20%MC, while in possession of evidence, tests and reports showing that this couldn’t be practically achieved or monitored.

BRANZ did not carry out durability testing on this timber, ignored the evidence of the 1952 Boron enquiry and somehow concluded that treatment was not necessary.

When it was obvious that their Appraisals were resulting in leaky, rotting buildings, they were resistant to change.

Whatever BRANZ may say in their defence, the true test was whether they were right.  Quite clearly they weren’t, but have never admitted it or copped any share of the blame or costs.

Read Part 2 of “BRANZ is to blame” where we look at the serious flaws in BRANZ’s Good Stucco Practice 1996 and their appraisals of face fixed claddings which supported building thousands of leaky homes.