Established in Paris in 1987 by Anne Lacaton and Jean-Philippe Vassal, the practice have designed commercial, educational, cultural and residential buildings. A connecting thread across their work is the desire to find what is essential in each situation and to create a modest language of architecture based on an economy of means. Whether it is their celebrated conversion of the Palais de Tokyo or their social housing refurbishments, Lacaton and Vassal make intelligent re-use of the existing, minimising new building through innovative design, and through an appreciation of the transformative possibilities in each situation. They maintain that ninety percent of what is required for most projects is already available on site. Philippe Lacaton traces this attitude to five years spent in Niger which he describes as a formative experience, where he witnessed first hand what could be achieved with very little through the innovation and creativity of those living in scarcity.

The practice have recently published a book, PLUS: Large Scale Housing Development-an Exceptional Case, on the transformation of social housing in the Parisian suburbs that demonstrates their design approach well. Here they make the case for alterations and remodelling rather than the demolition advocated by local authorities. Lacaton and Vassal maintain that demolition is not an environmentally friendly option, regardless of how green the replacement building may be. Instead they outline an approach for remodelling the dysfunctional buildings from the inside out, starting with the needs of the users and letting this dictate their form and look. Walls and façades are removed, balconies are added, communal spaces created, alongside the addition of a lightweight structure for a winter garden. These changes occur building by building with the ability to transform the character of the entire neighbourhood. Through a careful phasing of work, their approach also has the advantage of not displacing and scattering established groups of residents. The practice is currently implementing this strategy on a sixteen storey block of flats in the 17th arrondissement of Paris and a housing block on a high-rise estate in La Chesnaie, Saint-Nazaire, France.

Lacaton and Vassal state that the first task of the architect is to think, and to decide whether to build or not. They see their role as extending far beyond just building, creatively engaging with the legal and regulatory aspects of each project. Famously, they often manage to stretch budgets far beyond the norm to create spaces that, whilst not according to accepted niceties of finish and surface, are incredibly generous. For example, their social housing project in Mulhouse, France provides twice the normal area by reducing costs through a careful handling of the construction programme and by using unusual construction methods, but to achieve this the architects also had to engage with tax regulators and housing law in order that tenants were not overtaxed. Horticultural greenhouses were erected on top of a concrete frame, with users adapting the raw aesthetic in huge variety of ways, and architects enjoying this apparent loss of control with relish.

• Palais de Tokyo
• School of Architecture, Nantes
• Social Housing, Mulhouse

Anne Lacaton and Phillippe Vassal, "Cité Manifeste," in Transparent Plastics: Design and Technology, ed. Simone Jeska (Basel: Birkhäuser, 2008), 86-91.

Anne Lacaton and Phillippe Vassal, "It'll be nice tomorrow - The beauty of the obvious," Archilab, 1999, http://www.archilab.org/public/1999/artistes/laca01en.htm

"Jean Philippe Vassal Interview / Lacaton & Vassal / Part 1 & 2 / 0300TV," http://www.0300tv.com/2009/05/jean-philippe-vassal-interview-lacaton-vassal-part-1/; http://www.0300tv.com/2009/05/jean-philippe-vassal-lacaton-vassal-feb-2009-part-2/

"Feature: Architects' Offices.," A + U: Architecture and Urbanism 424, no. 1 (2006): 162.

"It Will be Beautiful Tomorrow: The Work of Lacaton & Vassal," Life Without Buildings, http://lifewithoutbuildings.net/2004/11/new-to-me-lacaton-vassal.html

Pamela Buxton, "Comfort and Joy," Building Design, 2004, http://www.bdonline.co.uk/story.asp?sectioncode=429&storyCode=3043747

Andreas Ruby, Ilka Ruby, and Dietmar Steiner, eds., Lacaton & Vassal (2G Books) (Barcelona: Gustavo Gili, 2007).

Axel Simon, "Social housing, Mulhouse: Anne Lacaton and Jean Philippe Vassal," A10: New European Architecture, no. 3 (2005): 33-35.

Catherine Slessor, "Nantes School of Architecture, Nantes, France: Lacaton & Vassal," Architectural Review 225, no. 1348 (2009): 68-73.

Robin Wilson, "Art in process: the Palais de Tokyo, a showpiece of the 1938 Paris exposition, has been re-opened after years of inactivity and decay. It is again a dynamic exhibition venue, but in a way that would never have been imagined 60 years ago," Architectural Review (2003), http://findarticles.com/p/articles/mi_m3575/is_1272_213/ai_98831552/

"The question of monumentality for me is no longer important, and you can replace this by other things which are generosity and poetry, and to make something where people can have some emotions."
- Philippe Lacaton; http://imomus.livejournal.com/220762.html

'Each flat has to become a villa, it means that each flat has no more to stay behind a window but in front of each window it has to be now a new door, opening to a very large balcony-wintergarden. And at this moment the relation between inside, outside totally changes and you are no more in a flat, you are in a villa.'
- Philippe Vassal; http://www.0300tv.com/2009/05/jean-philippe-vassal-lacaton-vassal-feb-2009-part-2/

• Ecosistema Urbano