Heritage Impact Assessment: junctions matter
'Always design a thing by considering it in its next larger context—a chair in a room, a room in a house, a house in an environment, an environment in a city plan.' Eleil Saarine (Finish-American architect)
Take it from a heritage consultant at work in the brisk built environment of Sydney and New South Wales—pivotal to any assessment of heritage impact is the navigation of the junction or link between old and new fabric. Ensuring that transition between significant fabric and an addition is vital to the success of a project, in terms of ergonomics, aesthetics, the conservation of heritage significance, and statutory compliance.
Junctions require deep consideration. They must be envisioned as more than just lines on an architectural drawing. If not studied, a poorly resolved interface between established and new elements risks a visual catastrophe, constructional ordeal, and long-term maintenance dilemma.
Stripped back to basics, junctions (in heritage contexts at least) are both buffers as well as points of integration between two built elements. They connect and separate at the same time. And their character is myriad. They can be designed so as to avoid all contact between the old and new altogether or be hidden or camouflaged. Alternatively, junctions can be declarative—denoting, even narrative, a transition between the layers of a place.
Traditionally, extensions and additions at most Australian buildings, particularly domestic, were accrued organically. Little conscious thought was given to articulating junctions. They were defined unassumingly and governed by expediency instead of design—a shift in material or change in building technique. In some contemporary situations these simpler responses remain viable.
When assessing the potential impact of a junction, I typically focus to varying degrees on three factors:
—the extent of change to original fabric,
—reversibility of the intervention (for instance, utilisation of ‘soft’ joints and the new supporting the weight of the linkway device), and
—design response to significant layers (roughly dividable between a respectful or interpretive approach), both internally and externally.
The glazed link—commonly in the form of a glass slot—is routinely promoted as an appropriate junction for the historic environment, applauded by planning/heritage departments as polite, quiet, and anonymous. In 2020, has the glazed become hackneyed? Probably not; however, I would push back against its perception as the default. One of the issues of the state’s development control plans, replete in exhaustive heritage ‘dos and don’ts’, is the setting down of an orthodox approach to change in heritage contexts. The specificity and inherent challenges of old places, more often than not, negate standardised policy.
In cases when a glazed link is offered as the answer, its important to understand how the material will perform. Too often, plans and CGI visualisations show glazing as if it were invisible and non-reflective. This presentation can run counter to built reality.
Another way of achieving a junction is via indentations or ‘shadow gaps’. This device revolves around the installation of a depression or notch, sometimes clad in a matte finish. When done well, it results in the eye passing quickly over the junction, allowing for the integrity (wholeness, honesty) of the original and introduced element to become legible.
Of course, there are a slew of other means of dealing with intersections. The point is that they matter. They can be the fulcrum around which the successful interface of the new and old can resolve and by which a sympathetic relationship is cultivated.