Not so standard

At a recent chat with a few industry professionals the conversation digressed to what I describe as a mild bitching session, but an intelligent one at that, regarding building standards and how some lack critical detail or are outdated and not keeping up with the changes and trends in the industry.

So after listening to the exchange of issues, a few came to my mind where some believe we’ve never got right or are outdated. One Standard I come across that always gets referred to when issues arise in waterproofing is AS4858 with wet area waterproofing. This Standard was launched 12 years ago and in hindsight it has 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 I hear membrane suppliers talk of how good their product is it often sounds like a group of guys talking about who has the longest one, that is the membrane with the longest elongation. 300%, 400%, 500% and > 700% some claim. Wow, after all the years where the industry needed a standard on wet area membranes and we directed the focus on comparing membranes as if we were stretching chewing gum. Although the testing requires a tensile strength result to be recorded, retention of tensile has no importance in 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.

All this and we 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; and 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 over with a surface finish I would’ve thought 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?

Another that comes to mind is the tiling standard AS3958.1 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 in this standard doesn’t deal with the types of surfaces tilers are facing on site around the country. Without naming brand names, I recently saw a case where a tiler grinded the top surface of a smooth structural sheet flooring to enable his tiles to bond, citing that when he tried to bond his tiles directly to the surface 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 to weaken with tile adhesion failure happening 12 months later resulting in the sheet manufacturer stating their product was compromised by grinding, leaving the tiler to carry the can with footing the repairs. More of these light weight composite substrates have entered the market, all with properties that no doubt has their individual features and benefits, however standards have not been progressed to accommodate how the industry handles them with the number of associated trades that have to work with or over these types of surfaces.

I hear the same with the painting/texture industry where industry professionals advise exterior surfaces are to 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 and how this lines up between the Masonry Structures AS3700 and AS/NZS 2311 Guide to the Painting of Buildings. I mentioned in a blog a few weeks back Welcome to The Timber Age 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 seems to be moving fairly fast and it seems the construction industry is not isolated from this either. Do we have the mechanism in place to ensure Building Standards are progressing at the same rate as change or do we need to review the process of how the Building Standards are arrived at? Probably time for us to look at our Standards without the standard approach.