Mainly intended for first-time buyers, Bouygues Immobilier's timber-frame houses combine affordability with quality, comfort and energy efficiency. Their secret is to combine the natural advantages of wood with industrialised construction processes.
A strategic choice for Bouygues Immobilier
Keen to enhance its portfolio of affordably priced housing, Bouygues Immobilier is adding timber-frame houses to its product range. There are several advantages to timber-frame designs: as well as being inexpensive and comfortable, they also meet Bouygues Immobilier's energy efficiency requirements.
Through its subsidiary Ossabois, a timber-frame specialist with over 30 years’ experience, and by using industrialised processes, Bouygues Immobilier can offer homes with BBC-effinergie® low-energy certification at affordable prices, unrivalled on the market. One-third of the houses delivered by Bouygues Immobilier in 2011 had timber frames. This proportion is likely to be maintained even as the number of new-built homes increases in coming years.
What is a timber frame?
A timber-frame house is neither a wooden house nor a mountain chalet. It simply uses wood rather than concrete or steel for its structural elements (walls and floors). Each element is thus made of assembled wooden panels which, after insulation, are covered with a conventional inner lining (plasterboard) and external cladding (timber, rendering). From the outside, a timber-frame house looks like any other house.
Timber frames were originally only used on single-family homes, but have now started to feature on larger buildings. In 2013, Ossabois entered the following markets:
- tourist residences (400 houses for Center Parcs in central France)
- student accommodation (orders from Crous for 200 student rooms in Nice and Chambéry).
The advantages of a timber frame
Only 7% of houses in France have a timber frame. The figure is 30% in Germany and rises to as much as 90% in North America. This success is due to wood’s many natural advantages.
- Five times lighter than concrete, wood has excellent mechanical strength.
- In a fire, wood burns ten times more slowly than concrete.
- Wood insulates twenty times better than concrete and offers better thermal and acoustic insulation.
- Wooden walls are less thick than concrete or brick, allowing for up to 15% more living space.
- Naturally environment-friendly, wood needs less energy during processing and captures large amounts of CO2 while growing.
The industrialisation of the construction process
The last great advantage of a timber frame is that construction can be industrialised, since the building's load-bearing structures are prefabricated at the factory and delivered ready for assembly on-site. As well as reducing manufacturing costs, this ensures consistently high quality through controls at the factory and at each stage of production and assembly. Industrialisation also considerably reduces construction time: a mere 12 months from design to completion for a detached house!
Ossabois, a premium partner
In order to guarantee the quality and cost of its timber-frame programmes, Bouygues Immobilier relies on its subsidiary Ossabois, a French timber-frame specialist with over 30 years’ experience.
Based in central France, Ossabois has two factories capable of producing timber frames for up to ten houses a day. Ossabois also guarantees that all its timber is certified under either the FSC (Forest Stewardship Council) or PEFC (Programme for the Endorsement of Forest Certification) schemes and is sourced exclusively from European forests.
In 2013, Ossabois won a number of major contracts, some of which were for serviced residences. Timber frames were originally used for single-family homes, but are now increasingly featuring on larger buildings.
Two questions to Philippe Morel, head of Bouygues Immobilier's Maisons France division
WHY HAVE YOU DECIDED TO DEVELOP TIMBER-FRAME HOUSES?
We wanted to come up with high-quality homes at very affordable prices. Our aim is to meet demand from potential customers overlooked by other developers: first-time buyers with limited incomes, often looking to move from rented social housing.
The timber-frame house soon became the obvious solution. Industrialised production means lower costs and shorter lead-times without any loss of quality. In addition, our timber-frame houses have BBC-effinergie® low-energy certification under the latest thermal regulations (RT 2012) and are fitted with pellet stoves that cut the energy bill by 30 to 40% in comparison with a conventional house, a key factor for buyers!
With all those advantages, why aren't timber frames more widely used in France?
Don't forget that the lower price is achieved through industrialisation, which means less architectural flexibility. Regional traditions are still very strong in France. For example, builders tend to use brick in the north and cellular concrete in the south because these are deeply rooted habits.
But things are moving forward and new timber-frame projects are springing up everywhere. And they are not only for single-family homes, since timber frames can also be used for apartment blocks or office buildings.
An exceptional building… boasting a timber frame!
Les Lodges, a highly innovative project at Chanteloup-en-Brie, east of Paris, includes 35 timber-frame houses designed by architects AW2. The adaptable, modular houses can be extended by adding prefabricated wooden modules, so that a three-room house can become a four-, five- or even six-room dwelling. Timber frames provide outstanding flexibility.
The project’s eco-friendly design also helps to reduce energy expenses and CO2 emissions. It was singled out by the French environment and energy management agency ADEME as “an exceptional building in the Paris region”.