Too many members of the construction industry don’t understand how the Building Code works, and that is a real concern.
I noticed a recent ad in the window of a local real estate agency for a city apartment. The 12 storey building was described as: Built in the 1950s, a very reliable era. As I had produced the architectural drawings for the building in the 1970s the ad fell a bit flat.
However, it did make a valid point that the second half of the last century produced some “reliable” buildings — until it all went seriously wrong in the 80s and 90s.
As the number of houses, schools and shopping centres wrapped in plastic sheeting continue to grow I can’t help wondering “where did we go wrong?”
Not that buildings haven’t always been prone to the occasional water-related issue, but what has been revealed since 2000 is much more serious and widespread.
To paraphrase a recent quote about leaking school buildings by Minister of Building and Housing Maurice Williamson in the New Zealand Herald: “The ministry went for least price wins. A few years later the whole lot’s turned to absolute crap. ‘Cheapest price wins’ is a mentality that we’re changing.”
While a welcome glimmer of good sense, the problem is it’s happening 25 years too late.
I remember asking a former client of mine — in this case a large US-based company — what quality standard they would prefer for their project. The client’s answer was succinct: “What’s wrong with the best?”
A great deal of time and effort has been expended by a number of well qualified industry members from various disciplines and a raft of changes introduced — for example, timber treatment and strength regimes, and more extensive compliance documents for claddings.
However, I am not convinced that this will be enough, and I am not convinced that the direction taken to overcome areas of industry weakness is the right one.
I am amazed by my industry’s lack of understanding of construction legislation. The difference between the Building Act, Building Regulations, Building Code statements and compliance documents is still a mystery to many.
How many still believe that E2/AS1 and other non-mandatory, so-called compliance documents form part of the Building Code?
How many product manufacturers understand how their products comply with the performance-based Building Code statements? How many know the difference between an acceptable solution, a verification method and an alternative solution?
Part of this misunderstanding arises from the terminology used. “Compliance documents” sound as if they are very important and almost certainly mandatory, but they are not. They are merely one pathway to compliance.
And an “acceptable solution” sounds much more mainstream than an “alternative solution”, but they carry equal weight. I wish a few more council inspectors recognised this fact.
The lack of any statutory status for industry guides such as BRANZ appraisals and New Zealand Standards is also seldom understood. Too many members of the construction industry don’t understand how the Building Code works, and that is a real concern.
Then there has been the increase in the coverage and use of acceptable solutions, in particular those concerning external roof and wall claddings. These are generic, cookbook-type solutions, introduced in an attempt to overcome serious weaknesses in how our timber-framed buildings were being designed, detailed and constructed.
As well as offering a false sense of security — i.e. if you comply with E2/AS1 everything will be all right — they are, by their very nature, arbitrary and non-specific. They fail to recognise that buildings are not built using “generic” products, but by using a diverse range of branded products and systems.
So many unwise design approaches were introduced during the 80s and 90s. More than any other reason this is at the core of the leaky buildings debacle.
In-line decks, face-sealed claddings, complex roof shapes and junctions, and an attempt to create the appearance of solidity over a lightweight timber frame. All these add a degree of difficulty and place pressure on getting it right — not just good enough, but exactly right.
Many of these design approaches are still employed today. And what has been introduced to alleviate possible water ingress? A 19mm wide vertical cavity, bottom ventilated only.
Can we really expect an industry struggling with levels of competence to provide a robust solution with only 19mm between success and failure?
How easy is it for poorly installed insulation to push the building wrap across this narrow gap and provide a convenient pathway for water entry? And the complexity of the detailing required to maintain this slender cavity at wall penetrations is an even greater worry.
I would much rather see an insistence on rigid overlays over timber framing — either plywood or strandboard — as is commonly employed in the USA.
Not only does this provide a solid second line of defence (I leave it to the experts to decide whether a wrap is also needed), but it significantly stiffens the timber frame and reduces the potential for movement.
A further concern is the lack of designer and client input on the building site and as part of the construction team. Consider the following list:
• Invited tenders, only from contractors known to the design team and client’s representatives
• Lists of subcontractors submitted for approval by the client
• Weekly site inspections by the design team
• Contingency sums on all contracts
• Monthly site meetings with the design team, contractor, sub-trades and client’s representative
• A clerk of works
• A site engineer
• Full shop drawings of all cladding elements, vetted and approved by the design team
• Samples and tests of materials and constructions
• Off-site weather tests of new or unusual construction elements — e.g. precast panels, window installations
• Regular quality assurance procedures signed off by the contractor and design team
• Maintenance retentions
• Enforceable watertightness and weathertightness warrantees signed by the head contractor.
All these were a normal feature of construction contracts in the 60s and 70s, and most disappeared from view in the 80s. Ring any bells?
And please, get rid of the unfair, ineffective “joint and several liability” approach to construction law.
A last person standing approach to who pays when things go wrong just doesn’t work. Just ask a few of the poor, desperate people struggling with how to pay for recladding their near-new home.