Font Size

- Aa +

Wed 2 Jul 2008 04:00 AM

Font Size

- Aa +

Losing your marbles

The stone cold reality about one of the region's most popular materials.

The stone cold reality about one of the region's most popular materials.

After realising marble's unique combination of load bearing capability and elegant appearance, civilisations in ancient Egypt and Mesopotamia used it extensively to construct the massive columns that have come to define their building style.

Marble has been a primary building component in Greece since the sixth century BC when local architects built the Athenian Treasury entirely of the material. During the same period, Pericles built the Parthenon as a beacon of the Acropolis and a symbol of Greek building superiority-again, entirely of marble.

Since that time, marble has been used to symbolise beauty and elegance in buildings throughout the world including the Palace of Versailles, St. Paul's cathedral in Rome, the gothic spires of the Duomo Cathedral in Milan, India's Taj Mahal and the elaborate nave of England's Salisbury Cathedral.

Fast-forward to the modern Middle East where marble is being used in myriad applications and increasing amounts. From the Burmese Teak that graces Dubai's Monarch Hotel to the tiger-eyed marble flooring of the Mall of the Emirates to the suppleness of the marble-clad floors and columns of Abu Dhabi's National Exhibition Centre (ADNEC), marble is being specified with ever-increasing frequency in both commercial and residential properties.

In fact, marble is being used so much in Middle Eastern residential projects that one architecture practice stated that almost 90% of its clients request large-scale marble applications.

"Because it's malleable, marble allows us to achieve architectural concepts that would be impossible with granite or ceramics or porcelain," says Mohammed, lead project engineer for X-Architects.

"All the new cutting and etching techniques are fantastic," adds Adrian Battisby, senior designer at WA International. "Before, marble had limited applications because people used to say we can't use it because it's too difficult to manipulate."

Yes, because of these reasons, marble can perform functions outside its original uses. And, yes, it is also true that in doing so, its value as an architectural material increases. But there seems to be little dispute within the industry that marble is specified in ever-increasing frequency for one reason: appearance.

"Within the hospitality sector we use marble for flooring and bathrooms because it's such a gorgeous material. It looks extravagant and impressive," says Battisby. "It's absolutely gorgeous on the floor or as a wall cladding material so we love to use it in all of our projects."

Experts throughout the industry agree that there are several natural stones that could perform better than marble-i.e. granite, travertine, sandstone-but are passed over because of the elegance of marble and the status it conveys.

"The appearance of the stone is unparalleled," says Mohammed. "Middle East clients are really drawn to marble flooring, especially for residences. The design, colour and appearance are what attract them."

A problem arises

It seems that with natural stones, as is the case in so many other areas of the newest Middle Eastern architecture, the most suitable solution is often cast aside in favour of that which is the most beautiful or extravagant.

In this new era of environmentally-conscious building, too many clients in the Middle East continue to place aesthetics above functionality or responsibility.

"We tend to go for what we want first," says Kevin McLachlan, interior design director at RMJM Architects. "Whatever suits the colour schemes and design are foremost, then we consider the performance."

If Middle Eastern architects, interior designers and clients are serious about making more eco-friendly choices in their buildings, the use of marble should be reconsidered.

The harsh Middle Eastern climate makes marble all but unsuitable for exterior applications and bad business practices often leaves it improperly maintained-both inside and out.But perhaps most importantly, using marble can actually subtract certification points in the LEED and Estidama New Buildings (ENB) measurement tools, which, in light of recent legislation, are now at the forefront of building practices in the UAE.

Marble, climate & performance

First, marble is a metamorphic rock which means that it has been subject to extreme temperature and pressure within the Earth's crust. This causes profound physical and chemical changes within the stone and It also means that marble can be classified into several categories based on texture, chemical and mineral assemblages. These variations are what cause the stone to be soft and porous, which undermines its effectiveness in external applications.

A soft, porous stone combined with extreme temperatures makes for a building/cladding material that performs poorly and is difficult to maintain. "Marble doesn't respond well to the external climate in this region. The higher the temperature, the more stress that is placed on the marble," explains Mohammed. "More stress on the marble leads to decay, which leads to a decrease in thickness. That ultimately leads to cracking."

"Decaying and cracking are huge problems with marble in the region," adds Annie Hayes, owner of Dubai-based StoneConcepts. "Once [marble] is damaged, it's damaged. You can't do anything with cracked marble."

In fact, according to Moreiras, Paraguassu & Ribeiro (2007), when marble is exposed to the environment of urban centres, pollution from sulphur oxide, nitrogen oxide, carbon monoxide and carbon dioxide, causes a measurable alteration in its ability to reflect light.

Moreover, due to their acidity, these elements actually precipitate a breakdown of the components in marble, which further leads to decay.

Furthermore, marble needs to be sealed properly-on all six sides of the slab-to retain its lustre and combat against decay.

But, ironically, in a climate not ideally suited for marble, where extra care should be taken to preserve the costly material, improper sealing is one of the most commonly cited errors.

"You need to seal all six sides when you're installing it, otherwise you get water absorbing in through the edges," explains McLachlan. "Ideally you want to dip the whole sheet in a solvent that will resist water and staining."

"All too often [marble] isn't sealed properly or it's sealed post-installation. Sometimes good building practices aren't adhered to. It's a shame; the salt gets in and begins to blister and decay the stone," adds Battisby.

The combination of acidic cleaning solvents-to which marble is particularly susceptible-poorly sealed slabs and prolonged exposure to the noxious elements in cigarette smoke could conceivably have an effect on interior marble similar to that of urban environments on exterior marble.

"The buildings here need to feel like palaces so we use marble. Cost and appearance are two of the most important factors when choosing marble," says McLachlan. "Performance of the stone can be an afterthought in this region."

Marble & procurement

An oft-cited ‘truth' in the marble industry is that the best variety of the stone comes from Italy. According to McLachlan, the Italian Supply Theory is a well-known fallacy.

"The stones you get in Italy aren't necessarily from Italy," he explains. "They can be mined in China and marketed under a different name in Italy. There is a huge variety of marble in Italy and you can tell the ones that are quarried there...some clearly come from China."

"Some of the smaller European quarries have been exhausted so people looking for a French stone could really be buying a Chinese stone," adds McLachlan.

If this is indeed a true representation of procurement within the industry, marble becomes even more suspect.

The embodied energy alone in a material that is quarried in China, transported to a market in Europe and then shipped to the Middle East could very easily derail a green building process.

"The marble in China is fine but I think it's more about quantity rather than quality," says Battisby. "We tend to be a bit wary of it. It can be very porous.... Ultimately it may not be appropriate."The problem is compounded when a locally sourced alternative is available but simply ruled out because it lacks the specified charateristics.

"You can get emperador medium marble from Italy, Saudi Arabia and Pakistan; it's the same stone but it looks different," says Battisby. "The Italian version from the same vein is beautiful, it has an even distribution of colour, but the Saudi version is very dense, it looks like concrete....It's all about the look," explains Battisby.

"We can be hemmed in to pick regional stones," says McLachlan. "Sometimes clients will specify that because it cuts down on transport and embodied energy, but the suppliers here don't have the quantity to support anything too large."

"Requiring 20,000 to 40,000m2 of one marble presents obvious consistency challenges. So, you've got to always have that in mind. Can I procure enough marble to keep it consistent?" adds McLachlan.

Just as in durability and performance, aesthetics, rather than accessibility, is the driving force in procuring marble.

Marble & green buildings

Both LEED and ENB call for architects and interior designers to use materials that are renewable and have been sourced locally. Given the logistics of procuring it, desirable marble fits neither of these criteria. However, to be fair, the jury is still out on the relationship of natural stones to green buildings.

According to an April 2008 statement from John Mattke, the co-chair of the Natural Stone Council (NSC) and the chairman of the NSC's committee on sustainability: "Buildings-and not cars like many might think-are the largest source of both energy consumption and greenhouse gas emissions in America and around the world."

As such, the NSC is working with the American Institute of Architects (AIA) and organisations around the world to more clearly define this relationship. On one hand, the use of natural stone in buildings comes with a high level of embodied energy in procurement, manufacturing and transportation, but natural elements offer literally tonnes of recyclable material.

Depending on which LEED components are carried over from the USGBC's version, the use of natural stone in architecture can garner credits for material reuse, building reuse, a low level of Volatile Organic Compounds (VOC) and the use of an innovative material.

A final word

Neither its beauty nor its historical relevance is disputed. Perhaps the best way to approach the marble issue is to question its appropriateness for the context in which it's being used.

Independent research suggests that marble has durability issues in highly trafficked areas, especially within the Middle Eastern climate. Industry experts agree that installation and maintenance of marble in the Middle East leaves much to be desired and, likewise, that poorly maintained marble and water absorption are the chief causes of material decay.

The energy embodied in procuring marble-especially when it's transported across the globe and back-is unparalleled in any other building material.

All of these reasons are compounded when considering granite, travertine and sandstone would all perform better-both inside and outside-in a Middle Eastern context. Moreover, all are more cost-efficient than marble but lack its lustre or elegance and thus, are often passed over.

While it's clear that natural stone plays some role in garnering green building credits, it's unclear how much carbon footprint from procurement is actually offset by its use.

Marble is pretty but we've come to a point in the building history of the Middle East where pretty isn't enough. The shift in architecture is toward efficient buildings that are environmentally friendly in every facet of the building process. What purpose does it serve for our exteriors and superstructures to be environmentally friendly if our interiors are clad with under-performing material and saturated with embodied energy?

RELATED LINK:Possible impossibilities

For all the latest construction news from the UAE and Gulf countries, follow us on Twitter and Linkedin, like us on Facebook and subscribe to our YouTube page, which is updated daily.