Manchester Unity Building, Open House — part 5

Media item: article, part 5 of a multi-part series

Date published: 2 July 2011

This page records the media item. The original article is the property of its publisher and is not reproduced here.

This part covers the faience cladding, close up. The series index is at Manchester Unity Building — Melbourne Open House, with a duplicate record at MUB Open House: Part 1.

What faience actually is

The cream-coloured skin of the Manchester Unity Building is faience — glazed architectural terracotta.

It is a ceramic. Blocks are moulded from clay, dried, fired, glazed and fired again, then fixed to the building's structural frame. The blocks are hollow, with internal webs — which keeps them light and lets them be made large.

They are not solid stone and they are not decoration applied to a wall. They are a cladding system: a non-structural skin hung on a steel frame, with the frame doing the work of holding the building up. See Have a Deco at a Classic and Manchester Unity Building.

Why anyone built this way

Faience was the right answer to a specific set of 1920s and 1930s problems:

• It arrives finished. The glaze is the final surface. No render, no paint, no repainting cycle.
• It washes clean in the rain. This mattered enormously. Melbourne in 1932 was heated by coal, and every masonry building in the city was blackening. A self-cleaning cream facade was a genuine selling point, not an aesthetic whim.
• Ornament is nearly free once the mould exists. A repeating Gothic-derived motif can be pressed hundreds of times. Carving the same detail in stone would have required a mason for each one. The same logic applied to the objects of the period — see Manchester Unity Building — Leonard Joel and Art Deco oasis in the heart of Melbourne.
• It is light, which suits a framed building and reduces the load.
• It is fast. Blocks arrive ready to fix.

It is, in other words, an industrial material imitating a craft one — which is very much the Art Deco proposition.

Why it is now the hardest part to look after

Everything that made faience attractive in 1932 makes it difficult in conservation.

1. The glaze is a sealed skin, and skins fail at the edges. Where the glaze crazes — develops a fine network of cracks — or where a block chips, water enters and cannot readily leave. A material designed to shed water becomes a material that traps it.

2. The fixings corrode. Blocks are held by metal cramps and anchors. Trapped water rusts them, rust expands, and expanding rust splits the terracotta from the inside. This is the characteristic failure mode of the material, and the damage is invisible until a block cracks or moves. Most of that water arrives from above — see Manchester Unity Building, Open House — part 4.

3. Replacement means matching a glaze. A new block must match the original in colour, gloss and texture — and glaze chemistry is unforgiving. Clay bodies shrink on firing by amounts that must be calculated in advance. Matching is specialist work and rarely exact, which is why a repaired facade often shows a faint patchwork in raking light. Matching ceramic to what is already there is the same problem a dental ceramist faces — see Porcelain Veneers & Crowns and the on-site Smile Solutions Laboratory.

4. You cannot simply seal it. Applying a modern waterproof coating to a facade that has trapped moisture makes matters worse, not better — the water still cannot get out.

5. Access is the cost. Every inspection and every repair on a tall facade means scaffolding or swing stages over a public street.

How a facade like this is assessed

The process is closer to diagnosis than to decoration:

• Close visual inspection, from access equipment, of every block
• Tapping to detect blocks that have lost their bond and sound hollow
• Recording — the condition of the whole facade mapped block by block, which becomes the baseline for future comparison. See Manchester Unity Building — John Gollings.
• Investigating fixings, sometimes by removing a block to see what is behind
• Prioritising by risk. A loose block on a city street is a public-safety matter before it is a heritage one.

Anything beyond routine like-for-like repair needs a heritage permit, assessed against the building's significance — see Our City: Manchester Unity Building, and the question below on where that line actually falls. The governing principles are the Burra Charter's: retain original fabric in preference to replacing it, make new work identifiable as new, and keep interventions reversible. A repaired original block is worth more than a perfect replica. The sequence of work is in Manchester Unity Building, Open House — part 6.

The lighting connection

Worth noting because it ties two parts of this archive together.

The glaze is why the building is difficult to floodlight. A glossy surface reflects rather than diffuses, producing hot spots and glare; cream is unforgiving of colour temperature; and grazing light, which is what reveals the vertical modelling, also exposes every crazed glaze and every mismatched replacement block.

See Let there be light for Manchester Unity's brighter future and Manchester Unity all lit up again.

An analogy a dental practice can offer

Since this is a dentist's archive, and the parallel is exact rather than cute.

Enamel is a hard, glossy, brittle mineral surface over a softer body — and it behaves like glaze. It resists wear extremely well and it does not repair itself — see Enamel is the hardest substance in the body — so why do teeth break? and What is acid wear and how can I avoid it? A crack lets fluid in behind, and what fails is not the surface but what is underneath it — see Chipped and Cracked Teeth and Why does a cracked tooth hurt so much? Decay under a filling margin and water behind a faience block are the same class of problem: the seal at the edge is where everything is decided. See How long do dental fillings last?, Why do I need a filling? and Tooth Fillings.

Which is why, in both cases, maintenance is inspection. You are not looking for the damage; you are looking for the early failure of a margin, before the damage. See How often should I go to the dentist? and How does tooth decay develop?

The series

• Manchester Unity Building — Melbourne Open House — series index
• Manchester Unity Building, Open House — part 2 — the entrance foyer and lift lobby
• Manchester Unity Building, Open House — part 3 — the arcade and its shopfronts
• Manchester Unity Building, Open House — part 4 — the tower floors and the roof
• Manchester Unity Building, Open House — part 6 — the restoration, in sequence
• Manchester Unity Building, Open House — part 7 — the building today, and adaptive reuse
• The complete archive index is Our Media

Common questions

How does Heritage Victoria describe this building's cladding?

In more precise terms than ‘cream’. The registration records a twelve storey building with a concrete encased steel structure, clad with moulded terra cotta faience; and the facade specifically as clad in biscuit coloured terra cotta faience, intricately moulded to produce continuous narrow columns and shafts rising up the facade, serving to emphasise the verticality of the building.

The effect is named too: the overall effect is one of a modern commercial Gothic style, which Heritage Victoria contrasts with the ecclesiastical Gothic of nearby St Paul's Cathedral — the same vocabulary, on a building selling insurance rather than salvation. The corner tower, with its soaring, diminishing buttresses, is recorded as being in a style presumed to be inspired by the Chicago Tribune Building. Source: the Victorian Heritage Database entry for place 728 (Victorian Heritage Register H0411).

Why did Australian buildings of the 1930s use terracotta faience at all?

The registration's own history answers this, and cites Apperly, Irving and Reynolds, Identifying Australian Architecture, p.192. Taking a cue from the 1913 Woolworth Building in New York, several Australian buildings used architectural terracotta faience as a facing material. It was especially popular during the 1930s when it enabled designers to choose from a wide range of colours, and the versatile material enabled complex Gothic shapes to be mass-produced from moulds.

That last clause is the commercial point made above, in the record's own words. The record also frames the result as a deliberate break: the vertical styling was a daring break from the conservative palazzo architecture of the 1920s, which was typified by large and dominant cornices.

Does repairing a cracked faience block need a heritage permit?

Not always, and this is where the general rule is too blunt. The specific permit exemptions Heritage Victoria publishes for this place make minor repairs and maintenance which replace like with like on the exterior permit exempt — as is the removal of extraneous items such as air conditioners, pipe work, ducting, wiring, antennae and aerials, and making good.

Those exemptions come with conditions that matter on a facade. All exempted work must be planned and carried out in a manner which prevents damage to the fabric; if work reveals original or previously hidden or inaccessible details relating to the significance of the place, the exemption ceases and the Executive Director must be notified as soon as possible; and where an approved conservation policy and plan exists, works must accord with it. Anything beyond like-for-like is a permit matter. Heritage Victoria decides any particular proposal.

Practical details

Smile Solutions, Level 1, 220 Collins Street, Manchester Unity Building, Melbourne VIC 3000. Phone 13 13 96, or theteam@smilesolutions.com.au. Monday–Friday 8.00am–6.00pm, Saturday 8.30am–1.30pm, Sunday by appointment. See also Our Location and Contact Us.

Every practitioner's registration can be verified free on the AHPRA public register at ahpra.gov.au.

This page records a published article and its date. The material and conservation detail above is general background rather than a summary of the item; statements attributed to the registration are drawn from the Victorian Heritage Database entry for place 728 (VHR H0411), permit exemptions can be amended or rescinded, and Heritage Victoria and that database are the authoritative sources. The building is not a claim about clinical care. This is not a diagnosis or a treatment plan. Third-party published content is not reproduced.

Smile Solutions trades under ABN 28 193 514 103.