Friday, July 17, 2015

Modular Housing Floats Their Boats

Outside the Box: It's time to take another look at factory-built homes

A floating community of prefabricated homes in the IJburg district of Amsterdam are affordable and indistinguishable from conventionally built homes. MARLIES ROHMER ARCHITECTURE + URBAN PLANNING / OTTAWA CITIZEN

Our frigid Canadian winters dictate not only how we construct homes but when. From spring to late fall, building sites are busy and slow down during the winter months. It makes one wonder why we haven’t adopted faster building methods when it comes to housing ourselves.

The answer lies in the post-Second World War boom era. Then, the need to house many immigrants, returning veterans, and their young families led to a revolution in homebuilding. Old methods had to be filed into history and new ones invented.

Saving valuable materials and shortening construction time by coordinating between the sizes of different components were the underlying principles of many inventions. The modularity of wood frame wall studs, batt insulation, plywood, and gypsum wallboard helped speed up production.

Yet, the process of building a home remains the same to this day. Products are shipped to the site and assembled manually by trades.

Canadians have so far failed to follow the lead of other countries such as Finland or Sweden with populations and climate similar to ours and Japan, where prefabrication constitutes a significant chunk of the housing market.

The IJburg project is one of the first to apply land-built prefabricated housing typologies to floating homes. The homes were built in a distant plant and then towed to the site and attached to jetties (floating walkways). AVI FRIEDMAN / OTTAWA CITIZEN

Why didn’t we embrace factory-built homes? Lack of economy of scale to justify investment in plants, no significant cost advantage, and the end product’s poor look made these homes unappealing to consumers and unattractive to builders.

Changing times and recent trends make it a splendid opportunity to revisit how and when we construct homes.

A visitor to a Scandinavian neighbourhood constructed with industrialized methods will not be able to differentiate these homes from other conventionally built structures. Attractive design, exterior projections, a variety of building materials and, above all, high-quality construction explain why these nations like prefab homes.

If you want to see the latest in factory-built dwellings, visit the IJburg district of Amsterdam in the Netherlands, where the Dutch have built their homes on water.

Designed by Marlies Rohmer Architecture + Urban Planning, the project has taken the form of a floating community. Impressively, it has produced homes at half the construction cost of land-based housing in the city.

A community built on water, a skating rink is just outside the door at IJburg in Amsterdam. MARLIES ROHMER ARCHITECTURE + URBAN PLANNING / OTTAWA CITIZEN

The houses offer an alternative to expensive Amsterdam canal houses in that they are affordable yet close to downtown. This project is one of the first to apply land-built prefabricated housing typologies to floating homes. The homes were built in a distant plant and then towed to the site and attached to jetties (floating walkways).

Three housing types cater to different living situations and price points. Completely private houses are available; these are detached units that rely on an individual flotation tank that holds them in place. Semi-detached houses combine two units on one such tank, while triplexes combine three residences. This last selection is geared toward the rental market and is, understandably, the most affordable.

The nature of the community’s master plan allows buyers to fit their house to their unique needs. It is a wonderfully flexible arrangement. For example, if a resident wished to have their house face the sunset or sunrise, it is, incredibly, a feasible option. They can select a desired location in the lake.

Three housing types cater to different needs and price points — singles, semi-detached and triplexes.AVI FRIEDMAN / OTTAWA CITIZEN

The units are modular and easy to mass produce, further saving on construction costs. The flotation tanks are made of double-reinforced concrete filled with polystyrene. When compared to traditional foundation types, this is a very inexpensive design.

Walls are prefabricated off-site, making on-site construction extremely simple. Once the houses are constructed using prefab parts, multi-house units can be grouped to a single flotation device. Construction materials are high-quality and long-lasting — and require minimal maintenance.

A result of quality construction, the floating houses of IJburg consume an average of 15 per cent less energy than standard homes. Gas, water and sewage services are supplied by insulated cables and flexible pipes. A heat pump and heat exchanger provide homes with heating and cooling. The surrounding water helps control the interior temperature of the buildings.

The mounting cost of housing in Canada combined with the introduction of new technologies makes it necessary to tackle new demands head on. Builders need to see prefabrication in much the same way as the car industry sees automobile assembly. The home can become the high-quality end product of a new industrial design and production process.

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