Facade Performance & the Rules 101
Façade performance & the rules 101
2 Formal CPD Points
Façade performance is directly connected to the impact of our buildings on the planet both in carbon omitted from heating and cooling equipment, lighting etc and also in carbon omitted in the making of the façade in the first place. While statistics vary, the façade, or building envelope, typically accounts for upwards of 15% of the total embodied carbon.
The role of facades
Facades need to work with roofs and other exposed surfaces to control temperature, sound, humidity, fire, and other external conditions, but they also need to allow for human factors, such as allowing us to see from the inside out and get light from outside. i.e.) glass. Unfortunately, these two factors are not complementary and in fact work against each other.
To deal with these opposing interests we’ve developed innovations to make glass perform better – from colour (darker the better), to interlayers and multiple layers in double and triple glazing. These innovations in glass are good enough at creating some balance for the competing factors, but not good enough for sustainability.
What do we need to know?
We need to consider every element together, from a building’s position to its use and the proposed materials. We need to explore ways a building’s external envelope can provide natural ventilation, to prevent energy input while also contributing usefully to its active energy requirements.
We also need to be aware that not all materials are equal in performance i.e.) a 5 mm piece of aluminium framing isn’t going to perform as well as an insulated build up with a vapour barrier, air cavities and multiple layers. We also need to know about the role of insulation, as the key measure of performance for a glazed façade, and solar heat gain and visible light transmission in terms of connectivity to the outside.
What are the rules we need to follow?
Section J of the Building Code of Australia has been a key influence on architectural responses for well over a decade and the primary performance standard that is used. Section J has continued to change over time as performance targets increase
Very arguably though, Section J should only represent the base level of our ambitions, our minimum standard, although we often treat it as the “gold standard” bar to cross.
How well do we understand all of this, and do we apply it to our projects?
Truthfully, it’s really confusing and hard to keep up with.
If we are honest as architects and building professionals, we have a lot going on and being across the latest thinking across all parts of the job is a constant challenge and some of the basics do tend to get forgotten from time to time.
To alleviate some of the misunderstandings and confusion around Façade Performance and Section J Mecca has brought together a group of façade and building code experts who will, explain the context of the façade performance by defining the role of facades, explore the opposing Performance Factors v Human factors, define the key terminologies and how they interrelate, explain the importance of window/wall ratios and discuss what we need to know about the performance of certain materials, build ups and systems and compare their performance.
Our experts will break down the concepts below by carefully explaining the:
Meaning of heat transfer & how it affects energy consumption
Meaning of U-value, R-value, SHGC
Comparison of typical façade materials (aluminium vs glass, double-glazing vs triple glazing etc.)
Comparison of typical façade systems (curtain wall vs window wall, vision area vs spandrel build-up, thermally improved vs thermally broken etc.)
What is required? (NCC, Section J, Basix etc.) and what does this mean for façades? (Window to wall ratio etc.)
Introduction of an integrative approach to façade design (as opposed to reactive compliance-checking)
Overview of Section J façade performance modelling pathways
Parametric modelling of high-performance facades
Façade performance and its influence on the carbon neutral pathway
