Fact file

There are over 10,000 floating homes in Holland alone and is expected to grow to 20,000 by the year 2020

In Berlin and Hamburg floating structures are being utilised for student and key-worker housing.

Britain led the way in this technology in World War II when they constructed the floating Mulberry harbour.

A brief background on floating and flood-resistant structures

For decades, floating and flood-resistant structures have delivered value both in water spaces and areas prone to flooding.

Large floating structures are made possible by linking pontoons together using steel cabling or large bolts. These pontoons can be guaranteed for 100 years without being taken out of the water with a maintenance regime consisting of yearly visual checks and ultrasound checks every 5 years. There is a large amount of historical data to support this. A particularly good example is a 70-year-old 800 sq. m Russian pontoon that had been in the Siberian ice flows acting as a weather station. When it was taken out of water for inspection, it was found to have no damage and was easily reissued with safety certificates to permit its continued use.

Floating concrete pontoons are made of concrete mixed with a polyglass and reinforced steel, often called Cement 500 or Cement 600. The thickness of the concrete wall is usually around 18-30cm depending on the weight of the home. NGM’s large mixed-use structure ha s a weight of 2000kg per square metre. They are made in a mould and can vary in size from small individual homes to large working platforms. In most marinas throughout the world, cement floating pontoons form the basic infrastructure that allows boats to moor and people access to them from the land.

The cement pontoons and platforms make for a perfectly rigid, stable and sound surface or base from which to build large as well as small homes and apartment structures. The visible part of the cement above the waterline can be clad in a variety of ways to become a distinguishing feature of the house. Depending on the volume and the weight of the building, the draught line lies anywhere between 0.8m and 2.8m. The freeboard or height above water level can range between 0.5m and 3m.

On floodplains, the structures can rest on stilts while the tide is out, or in a cement sleeve that is built into the subsoil. Thereby, the home is not permanently floating but it has the capability of dealing with a flood situation – rising and falling within the sleeve secured by piles holding the structure upright mitigating stability issues.

NGM has been inspired by examples where innovative design solutions have created value in challenging environments throughout the world such as in the following examples.

	Venice* Venice is one of the best examples of waterside value creation, showing that being close to the water increases the value of the buildings.
	Flood-resistant homes, Maasbommel, Holland* The “can-float” flood resistant homes in Massbommel, Holland, have been such a success that a further 15 Dutch provinces have approved similar developments. A total of 1200 "can float" homes will be built by 2012. These homes are built on the wrong side of the flood defence. The development paid for the new flood defences which resulted in greatly reduced flood risk for the town of Maasbommel allowing the town's homes to be insurable following large floods in 1992 and 1995.
	Floating King Pacific Lodge, British Columbia, Canada* The five star floating King Pacific Lodge hotel in BC, Canada, sits adjacent to greenbelt protected land and has been a great success.
	Floating greenhouse, Holland* Floating greenhouses are being used to reclaim hundreds of thousands of acres of low-lying farmland that is being purposely flooded due to the effect of saline intrusion. The greenhouses will be connected using floating roads of which there are many examples throughout the world.
	'Sphinxes' development, Holland* The Sphinxes development, comprising five buildings, was constructed on the waterfront has been a great success and incorporated the parking for the residents in the concrete bases of the buildings.

*buildings not designed or built by NGM