Not So Standard
During a recent chat with a few industry professionals the conversation digressed to what I describe as a mild bitching session, albeit an intelligent one, regarding building standards and how some lack critical detail or are outdated and not keeping up with the changes and trends in the industry.
So, after the exchange, a few issues came to my mind that some believe we’ve never got right. One standard that always gets referred to when issues arise is AS4858 with wet area waterproofing.
This Standard was launched 12 years ago and, in hindsight, it’s missed a number of critical areas for waterproofing membranes. AS4858 has a major focus on the elongation values of membranes, measuring the elongation of products after exposure to bleach, detergents, and water.
Now, when membrane suppliers talk about how good their product is, it’s a ‘size matters’ comparison of the membrane with the longest elongation. 300%, 400%, 500% and up to 700%.
Wow! After all the years where the industry needed a standard on wet area membranes and we’re comparing membranes to stretched chewing gum.
Although testing requires a tensile strength result to be recorded, retention of tensile has no importance with membranes meeting the durability pass.
There is also a water vapour transmission result recorded, along with water absorption of the cured membrane and a reference to additional testing on particle board flooring, which is seldom used in bathrooms anymore.
Critically, we’ve overlooked measuring what really counts;
• how water tight membranes are
• permeability to water pressure
• membrane adhesion to wet area surfaces after exposure to flooding/immersion
• adhesion of surface finishes to membranes such as screeds and adhesives
• membrane adhesion to wet area accessories such as plumbing items, sealants, flashings etc.
There are probably more out there, but this is the list that common wet area membrane failures show up, with no reference point to AS4858.
Considering 99% of wet area membranes are covered with a surface finish, surely measuring the surface property of a membrane to enable wet area finishes to bond over it, has more value to the construction industry than how a dried film of membrane handles a surfactant detergent such as Teric 8 - which most labs find difficult to source.
Time for a Standard review?
The tiling standard AS3958.1 also comes to mind, which guides on how to fix ceramic tiles. With the increasing number of light weight, sheet surfaces that have entered the market as both floor and wall substrates, much of the detail doesn’t cover with surfaces that tilers are facing, on site.
Without naming brand names, one case showed a tiler grinding the top surface of a smooth structural sheet flooring to enable his tiles to bond, citing that when he tried, he had tiles de-bonding with little force.
Cutting a long story short, grinding the top surface resulted in the integrity of the sheet substrate weakening with tile adhesion failure happening 12 months later. The result: the sheet manufacturer stated their product was compromised by grinding, leaving the tiler to foot the repair bill.
More of these light weight composite substrates have entered the market, all with individual features and benefits, however standards have not progressed to accommodate how the industry handles them, with all the associated trades that must work with or over these surfaces.
I hear that painting/texture industry professionals advise exterior surfaces must be covered with a 3 coat acrylic, protective coating system, while many buildings are finished only with a 1-2 coats of acrylic paint.
There seems to be ambiguity with the Masonry Structures AS3700 and AS/NZS 2311 Guide to the Painting of Buildings.
My recent ‘Welcome to The Timber Age’ blog noted that CLT timber construction is here and will be more active. Do we have the standards to enable other trades to work over these types of innovations?
Everything around us is moving fairly fast and it seems the construction industry is not isolated from this. Do we have the mechanism in place to ensure Building Standards are progressing at the same rate of change or do we need to review the process of how Building Standards are arrived at?
It’s time to look at our Standards without the standard approach.