Why Re-Cladding May Be A Big Mistake – The Logical and Low Cost Alternative

The popular misconception that re-cladding is required for plaster clad buildings with a few leaks is wrong, pushed by re-cladding companies and councils to suit their own agendas.  Many home-owners are unnecessarily spending a fortune, thinking that they don’t have a choice.

In this article, we discuss the mature alternative that solves the issues logically, leaving more money in the pocket of the homeowner and doesn’t subject them to the stress and disruption of re-cladding.


All Houses Leak – But That Doesn’t Mean “Re-Cladding”

There have always been numerous places where water may leak into a building. Traditionally, houses were built with three layers of protection:

  • boron treated framing to a level where the expected leaks did not cause damage,
  • ventilation required for external framing , to dry out any dampness if there were leaks,
  • windows, doors, decks and penetrations had to have proper flashings to keep out the water.

A series of unfathomable decisions then led to a progressive reduction in building durability and weathertightness:

  • from 1992, houses had inadequate treatment protection to the framing. Between 1998 and 2005 often had untreated external wall framing.
  • the requirement for ventilating timber in the New Zealand Standards was ignored. Direct fixing of cladding (no cavities) allowed, with no additional protection to compensate for the lack of drying.
  • consents and Code Compliance Certificate issued to houses without cavities and without adequate flashings or adequate means of preventing leaks.

The result was wet, unprotected framing that stayed wet, then decayed….then the leaky homes scandal erupted.

Now all monolithic clad or plaster clad houses are tarred with the stigma that they might be leakers or rotting and that they should be worth less money.

A whole industry has emerged, promoting re-cladding as the solution when there are  any leaks or decay.

However not all external framing decays. Not all framing gets wet, and dry framing does not need a cavity as it is already dry. If walls are dry, then whatever flashings are in place are working.

It is 100% possible to make a plaster clad house just as dry and safe as any other house –  without spending hundreds of thousands of dollars on re-cladding.

It’s time to be sensible about our houses and make decisions that stack up with the facts.


Why Do Re-Cladding Companies and Councils Want Houses Re-Clad?

 The answer to the first part is obvious.  These companies, and the consultants who refer homeowners to them are set up to promote re-cladding.  This business is worth hundreds of millions of dollars.  They offer no alternatives, so re-cladding is recommended for any plaster-clad house with even a few minor issues.  We have seen dozens of instances where a full re-clad has only revealed a couple of small leaks.

The question of why the councils want you to re-clad is a little more complex but maybe even more insidious.  On the surface, the process of designing a re-clad, obtaining a building consent, having council inspections then having a new  Code Compliance Certificate makes total sense. The re-clad house has cavity construction, is weathertight and meets a reasonable durability standard.

Behind all of this though is Council’s knowledge of the potential liability for issuing consents and CCCs in the first place for buildings that are likely to leak and rot prematurely.  Now, when they process consents for re-clads, they ensure as far as they possibly can that all of the defective work that they approved 20 or more years ago is now gone.  That is one reason why re-clads are so expensive – you are paying to fix all of those bad design, construction and material decisions that the council should never have passed in the first place.

However, now it’s to late to hold the council to account.  Homeowners are on their own. So how do they keep their houses safe while avoiding the re-clad?

Re-Cladding Doesn’t Fix The Biggest Problem

Whilst the popular perception is that monolithic plaster claddings were the main cause of leaky buildings, this is not correct.  The problems arose as a combination of the factors listed above; undertreated timber, no cavities, and designs that didn’t keep the moisture out of the framing.

The re-cladding process has evolved considerably since the early 2000’s.  Many early re-clads failed again because important defects were not removed. We are now up to about Re-Clad Version 10 as Councils and re-cladders find more and more things that need to be removed, replaced or altered to get the re-clad through the ten year warranty period.  No doubt in another ten years, re-clads will be even more complex and expensive, as lessons learned from the todays re-clad failures are put into place.

However, the biggest underlying defect, not fixed by re-cladding, is the defective undertreated or untreated timber.  During the re-clad, any decayed or discoloured timber is replaced and any ‘good’ remaining timber is treated with a brush on boron treatment.  Experiments show this is not very effective at controlling decay if there is another leak.

That’s right. You spend hundreds of thousands on a re-clad, but much of the structure of the house is still defective and vulnerable to decay.

The  Mature Approach To Maintaining Plaster-Clad Houses

But what if you could locate and repair all of the leaks in the house and the damage to the timber is only minor?

And what if you could stop the leaks and kill off any decay?

And what if you could treat the timber so it won’t rot in the future?

And what if you could monitoring  the house in case any new leaks started?

Would you really want to spend money on a re-clad, when for a tiny fraction of the cost you could still have a safe, dry house?

What if you could prove to potential buyers that the house doesn’t leak, isn’t rotting and can be maintained indefinitely.

If all of these “ifs” were true, should there still be a ‘stigma’ attached to the house when it comes time to sell?

Wouldn’t this be a more mature way of approaching the issue rather than automatically assuming the house needs re-cladding?

We aren’t suggesting that re-cladding is never needed because for some houses there just is no alternative.  However this should be a last resort rather than the default approach.

Most home owners can’t afford a re-clad but just want to live in a safe, dry house and keep it that way.

Targeted Repairs and Treatment vs Re-Cladding 

In 2005, the Moisture Detection Company patented the Mdu Moisture Detection Probes, installed discretely through the skirting boards in thousands of NZ homes.  This is the most sophisticated, accurate, moisture monitoring system available, and is simple and cost effective.

Once the probes are in all weathertightness risk locations , you have detailed information on any wet framing, any decay and what, if any timber treatment was used.

From that position of knowledge, you make informed decisions about what to do next; do nothing, do targeted repairs and treatment, or go on for the full re-clad.

Targeted repairs and treatment have these goals:

  • Stop the leaks and modify defective details to manage or stop future leaks.
  • Ensure that timber that may be affected by current or future leaks is protected by adequate treatment.  If the timber is untreated then post-treat with RotStop.
  • Remove and replace decayed timber if it is affecting the structural integrity of the house – otherwise just treat it and leave it.

Homes can be saved, remain healthy and liveable and for a lot less anxiety and costs. The Building Act does not mandate that no decay is allowed in a building. It does not even mandate no leaks. What it does mandate is that leaks are not to progress to cause structural problems, which is limited to load bearing, bracing and maintaining secure claddings and linings. External walls are often over engineered, with safety margins of 50% or more.  Leaving minor decay that has been treated in some walls has no effect on the structure and remains in full compliance with the Building Act.

Compare this re-cladding where any timber within one metre of visibly stained wood is marked for replacement. This means expensive replacement even if the staining is due to the framing getting wet during construction and is still good, sound timber.

Moisture Probe System Schematic

Moisture Detection Company Philosophy

  • Gather evidence with Mdu Moisture Probes before making any big decisions or spending big money,
  • Locate and repair the leaks using the evidence from the probes,
  • Identify vulnerable timber, and treat it in-place with RotStop to kill decay and protect against future leaks,
  • Replace timber only when decay is serious or affecting structural strength,
  • Monitor for new leaks, and build a history of dryness by reading the Moisture Probes regularly,
  • Plan repairs and modifications to reduce weathertightness risks

Homeowners who adopt this process maintain and improve their homes.  They also have a comprehensive package of documentation to prove to buyers that their house does not leak, and is safe to buy.

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