How to build a gingerbread house – or an entire gingerbread city

Behind the beautiful glazed facades of today’s shiniest sky scrapers stand skeletons of columns and beams. The higher you build, the stronger the materials you require, says Diego Philipps, a senior engineer who’s worked on many a high-rise building in London, New York and the Middle East.

Yet he doesn’t usually transport his constructions to work on the bus – as he did with a spectacular three-storey tower, built almost entirely from gingerbread and gummy bears. This was Philipp’s entry for engineering consultancy WSP’s gingerbread competition, which attracts entries from structural engineers behind some of the capital’s tallest skyscrapers, from the Shard to 22 Bishopsgate. “There is a big difference between building a normal skyscraper and a gingerbread tower,” admits Philipps, associate director in property and building at WSP.

Gingerbread houses – often painstakingly made and magically decorated – are part of Christmas, and date back to the 1600s or earlier, according to food historians. Today, cooks vie to build the most opulent and ornate gingerbread houses, and millions of kits are sold every year. Yet construction is tricky, even for the most highly qualified engineers.

“When we build tall, the first thing we think about are external forces such as wind or earthquakes. Typically, we’ll use concrete or steel,” says Philipps. “With gingerbread, we only have to worry about gravity.” Engineers entering the fray also don’t have to worry about downdraughts – the fierce gusts at ground level generated by some high-rise towers. They have merely to cope with a lack of foundations and the limits of their baking.

Precision is critical, says Philipps, who deployed a tried and tested gingerbread recipe, sourced from the BBC. He built his own template for 12 rectangular panels (90 x 20mm) – to form three separate towers which could be stacked. For the windows, he used a square mould to pierce the raw dough, which he’d rolled out to 5mm thick.

He baked his gingerbread for 15 minutes at 180 degrees Celsius. “During construction, you encounter many difficulties – not least how you can transport large amounts of concrete, or how to use a crane to manoeuvre large steel beams 50 feet up. Here, your limits are the size of your oven – which determines the biggest panel you can bake. And you have to be careful not to break it.”

How do panels behave when fabricated horizontally and tilted to vertical during installation? “These are the types of questions we ask when designing a building,” says Philipps. He warns to be aware that gingerbread includes a raising agent. “After you bake it, it’s bigger. That doesn’t happen with concrete or steel – you’ll need to trim the gingerbread when it’s still warm and soft.”

Five minutes before the gingerbread is fully baked comes the opportunity for artistic flourish – in this case, gummy bears. Put a coloured pastille in each window cavity and bake for another five minutes until they melt to fill the gap, Philipps recommends. “I’ve seen people bake church-style stained glass windows with these,” he says. “That’s possibly a little ambitious.”

When creating a tower, engineers need to consider the critical aspect ratio – the height versus the width of the structure at its narrowest point. Philipps went for a conservative 7:1. “This is the norm – most London towers are built to this ratio.”

Perhaps in next year’s competition, Philipps might feel bullish enough to try a skinny tower. “There has been an explosion of super-slender blocks in New York,” he says. A recent crop of luxury residential towers have been built with ratios of up to 13:1, in order to squeeze the most value from a constrained city centre plot. By far the most extreme is a tower planned at 437.5 metres with a 24:1 ratio – 111 West 57th Street. “This beats them all,” says Philipps, who doubts a gingerbread tower could survive these extreme dimensions. The taller you go, he says, the stiffer and stronger the structure needs to be.

Royal icing made from egg white and icing sugar is the critical bonding agent. “Just as with a real building, when you place panels vertically, each panel wants to fall outwards – and that’s exactly what happened to me. Remember this building has no floors which could help hold everything together.”

Instead, he resorted to binding his three separate towers together with bootlaces, until icing set hard. When he began to stack one tower on top of the other to create a 70cm tall tower, structural integrity was severely tested. “I had to use tape,” he admits. “It was a bit of a cheat. I realised the imperfections of the panels would create an eccentricity at the point of contact of the towers, and the weight of the structure would cause panels to open.”

Happily, he says, gingerbread’s compressive strength is high, whereas its tensile strength is nothing to write home about. “Stack it high and gingerbread can very easily support its own weight,” he says. “But if you pull it, it will crack very easily.”

Given his time again, Philipps would make each successive tower smaller in diameter, and insert a floor between each tower for structural stability. Even the Burj Dubai – the tallest building in the world – has 27 reductions in floor size to control wind shear (the force that wind exerts on a building).  “I think it’s fine to cheat with a little cardboard between floors – we don’t need to be too purist.”

He’s got big ambitions for future contests. In a previous year, he created a gingerbread Burj-al-Arab. Curves are no problem; he used the side of a bowl. This time he’d like to bake a copy of the thin concrete shell structures created by acclaimed 20th-century engineer Felix Candela . “I’ll have to make my own mould. But anything is possible.”

Gingerbread: Build it and they will come

• One of the largest gingerbread houses ever made had an internal volume of 1,110m3 (39,201.8 cubic feet) and was built in Bryan, Texas, as a charity fund-raiser in 2013 (source Guinness World Records). It measured 18.3 x 12.8m, and was 6.1m tall at its highest point. It contained nearly 36 million (35,823,400) calories.

• Every Christmas, the White House welcomes a replica of the building within the State Dining Room – last year’s was covered in white chocolate.

• Stockholm Central Station hosted a life-sized gingerbread house in 2009, made from around 300kg of flour and 110kg of sugar to make nearly 700 kg of dough.

• From the Parthenon to Stonehenge to the Eiffel Tower, some of the world’s most iconic buildings have been recreated in gingerbread.

• Now in its third year, the London’s V&A museum hosts the Gingerbread City – an exhibition featuring more than 50 gingerbread buildings designed and created by architects, designers and engineers, as a celebration of their imagination. A selection of this year’s buildings are pictured above.

• All entries to the Annual National Gingerbread House Competition held in Asheville, North Carolina, must be 75 per cent gingerbread and completely edible. In 2017 – the 25th year the event has run – Ann Bailey won the adult category with her gingerbread depiction of ‘A Christmas Carol’ by Charles Dickens.

Behind the beautiful glazed facades of today’s shiniest sky scrapers stand skeletons of columns and beams. The higher you build, the stronger the materials you require, says Diego Philipps, a senior engineer who’s worked on many a high-rise building in London, New York and the Middle East.

Yet he doesn’t usually transport his constructions to work on the bus – as he did with a spectacular three-storey tower, built almost entirely from gingerbread and gummy bears. This was Philipp’s entry for engineering consultancy WSP’s gingerbread competition, which attracts entries from structural engineers behind some of the capital’s tallest skyscrapers, from the Shard to 22 Bishopsgate. “There is a big difference between building a normal skyscraper and a gingerbread tower,” admits Philipps, associate director in property and building at WSP.

Gingerbread houses – often painstakingly made and magically decorated – are part of Christmas, and date back to the 1600s or earlier, according to food historians. Today, cooks vie to build the most opulent and ornate gingerbread houses, and millions of kits are sold every year. Yet construction is tricky, even for the most highly qualified engineers.

“When we build tall, the first thing we think about are external forces such as wind or earthquakes. Typically, we’ll use concrete or steel,” says Philipps. “With gingerbread, we only have to worry about gravity.” Engineers entering the fray also don’t have to worry about downdraughts – the fierce gusts at ground level generated by some high-rise towers. They have merely to cope with a lack of foundations and the limits of their baking.

Precision is critical, says Philipps, who deployed a tried and tested gingerbread recipe, sourced from the BBC. He built his own template for 12 rectangular panels (90 x 20mm) – to form three separate towers which could be stacked. For the windows, he used a square mould to pierce the raw dough, which he’d rolled out to 5mm thick.

He baked his gingerbread for 15 minutes at 180 degrees Celsius. “During construction, you encounter many difficulties – not least how you can transport large amounts of concrete, or how to use a crane to manoeuvre large steel beams 50 feet up. Here, your limits are the size of your oven – which determines the biggest panel you can bake. And you have to be careful not to break it.”

How do panels behave when fabricated horizontally and tilted to vertical during installation? “These are the types of questions we ask when designing a building,” says Philipps. He warns to be aware that gingerbread includes a raising agent. “After you bake it, it’s bigger. That doesn’t happen with concrete or steel – you’ll need to trim the gingerbread when it’s still warm and soft.”

Five minutes before the gingerbread is fully baked comes the opportunity for artistic flourish – in this case, gummy bears. Put a coloured pastille in each window cavity and bake for another five minutes until they melt to fill the gap, Philipps recommends. “I’ve seen people bake church-style stained glass windows with these,” he says. “That’s possibly a little ambitious.”

When creating a tower, engineers need to consider the critical aspect ratio – the height versus the width of the structure at its narrowest point. Philipps went for a conservative 7:1. “This is the norm – most London towers are built to this ratio.”

Perhaps in next year’s competition, Philipps might feel bullish enough to try a skinny tower. “There has been an explosion of super-slender blocks in New York,” he says. A recent crop of luxury residential towers have been built with ratios of up to 13:1, in order to squeeze the most value from a constrained city centre plot. By far the most extreme is a tower planned at 437.5 metres with a 24:1 ratio – 111 West 57th Street. “This beats them all,” says Philipps, who doubts a gingerbread tower could survive these extreme dimensions. The taller you go, he says, the stiffer and stronger the structure needs to be.

Royal icing made from egg white and icing sugar is the critical bonding agent. “Just as with a real building, when you place panels vertically, each panel wants to fall outwards – and that’s exactly what happened to me. Remember this building has no floors which could help hold everything together.”

Instead, he resorted to binding his three separate towers together with bootlaces, until icing set hard. When he began to stack one tower on top of the other to create a 70cm tall tower, structural integrity was severely tested. “I had to use tape,” he admits. “It was a bit of a cheat. I realised the imperfections of the panels would create an eccentricity at the point of contact of the towers, and the weight of the structure would cause panels to open.”

Happily, he says, gingerbread’s compressive strength is high, whereas its tensile strength is nothing to write home about. “Stack it high and gingerbread can very easily support its own weight,” he says. “But if you pull it, it will crack very easily.”

Given his time again, Philipps would make each successive tower smaller in diameter, and insert a floor between each tower for structural stability. Even the Burj Dubai – the tallest building in the world – has 27 reductions in floor size to control wind shear (the force that wind exerts on a building).  “I think it’s fine to cheat with a little cardboard between floors – we don’t need to be too purist.”

He’s got big ambitions for future contests. In a previous year, he created a gingerbread Burj-al-Arab. Curves are no problem; he used the side of a bowl. This time he’d like to bake a copy of the thin concrete shell structures created by acclaimed 20th-century engineer Felix Candela . “I’ll have to make my own mould. But anything is possible.”

Gingerbread: Build it and they will come

• One of the largest gingerbread houses ever made had an internal volume of 1,110m3 (39,201.8 cubic feet) and was built in Bryan, Texas, as a charity fund-raiser in 2013 (source Guinness World Records). It measured 18.3 x 12.8m, and was 6.1m tall at its highest point. It contained nearly 36 million (35,823,400) calories.

• Every Christmas, the White House welcomes a replica of the building within the State Dining Room – last year’s was covered in white chocolate.

• Stockholm Central Station hosted a life-sized gingerbread house in 2009, made from around 300kg of flour and 110kg of sugar to make nearly 700 kg of dough.

• From the Parthenon to Stonehenge to the Eiffel Tower, some of the world’s most iconic buildings have been recreated in gingerbread.

• Now in its third year, the London’s V&A museum hosts the Gingerbread City – an exhibition featuring more than 50 gingerbread buildings designed and created by architects, designers and engineers, as a celebration of their imagination. A selection of this year’s buildings are pictured above.

• All entries to the Annual National Gingerbread House Competition held in Asheville, North Carolina, must be 75 per cent gingerbread and completely edible. In 2017 – the 25th year the event has run – Ann Bailey won the adult category with her gingerbread depiction of ‘A Christmas Carol’ by Charles Dickens.

Helena Pozniakhttps://eandt.theiet.org/rss

https://eandt.theiet.org/content/articles/2018/12/how-to-build-a-gingerbread-house-or-an-entire-gingerbread-city/

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