Hollow joints made in the thickness of an item system
Hollow joints made in the thickness of a system of ites 'abonons' abononpasscrée my account connecting research magazine magazine newsletters services for offerings of the exploitations of the work receivables BTPWebinarsindes-INDEXCONSTRUCTIONS and TALENTS MONTMESMESMESMESMES MESdirect
The facade of the Niwa collective housing building in Vanves has a first in France: a junction of deep hollow joint panels with the groove of the insulation.
L'agence parisienne Kengo Kuma & As-sociates (KKAA) a remporté en 2014 le concours pour un projet de cinq bâtiments d'habitation, totalisant 164 logements en R+4 à Vanves (92). Sur des parois en béton banché, le dessin de façade proposait une relecture du jardin minéral japonais - le nom du projet, Niwa, signifiant « jardin » dans la langue nippone. Les architectes souhaitaient jouer sur le contraste des matériaux naturels, entre le bois des brise-soleil et des panneaux de façade rappelant l'aspect de la roche reconstituée. Ces panneaux, de 250 cm de haut sur 80 cm de large, déclinent trois finitions différentes (couleurs et textures). Pour obtenir cet aspect, les architectes ont envisagé dès l'APS une solution d'enduit et engagé des discussions avec l'industriel Parexlanko. Après échanges, leur choix s'est porté sur l'association d'un enduit hydraulique EHI et d'enduits en granulat de marbre concassé de la gamme Marbri (lire encadré p. 42).
Two other options were in the running: a clothing made up of prefabricated coated panels, and a cladding solution reported on ite."They were not retained because the prefabrication posed the problem of predetermined dimensions, little in line with the continuities of heights desired, while the cladding involved visible unwanted hooks", explains the architect Charlotte Brussieux, project managerThe KKAA agency.The economic constraints of this very cut project, presenting a large facade area (more than 6,000 m²), also pleaded for the plaster on ite.
A groove in the insulation
However, this choice posed a major challenge, insofar as the drawing of the facade provided a very cut aspect of the panels, separated by deep hollow joints of 30 mm vertically and 20 mm horizontally. “There are already hollow joint techniques on coating, but only in the thickness of the finish. For example, we can arrange this seal in the coating underlayers for a maximum depth of 6 mm, or on the finish layer for a maximum depth of 2 mm. But on this project, the depth of the vertical joint required a new solution since it was a question of carrying out hollow joints in the thickness of the complete ite system, "summarizes Alexandre Pierre, project manager at Parexlanko. A mobile model in wallpapers was therefore carried out in early 2016 by the technical services of Parexlanko in their Malesherbes factory (45), in order to better understand the implementation and set up an application methodology.
"The first proposal consisted of a dilation joint whose dimensions were close to what was sought," says Pierre Alexandre.But the rounded and rude aspect of this joint did not satisfy the architects, who wanted a rectilinear joint more in line with the nervous drawing of the facade.The solution chosen therefore consisted in groorking the insulation - polystyrene panels thick grape of 14 cm - using a hot wire, to insert a profile designed specifically for the project.This profile is linked to the reinforcement, to which will then be applied, in a classic way, a plaster on ite, the coating under layers and then the finish.
A prototype to facilitate implementation
Initially planned in PVC, the profile will ultimately be made of gray postlated aluminum, for reasons of aesthetic integration.From a regulatory point of view, however, few obstacles have arisen.“The coatings used are already covered by a technical opinion notifying the arrangements to be taken to comply with the different fire, seismic, shock, rain, wind, etc. regulations, etc., underlines Pierre Alexandre.
It is more assembly and implementation that were unpublished.The final model will be presented to the architect Kengo Kuma for validation of the methodology in February 2016. From the start of the site in 2017, a prototype on a 1 scale on two floors with outgoing angle is built in situ.
Its role will be crucial to several titles. First of all, it is a question of setting the implementation: “The quantities are enormous, of the order of 5,800 linear meters (ML) of vertical profile, 300 ml of horizontal profile, and also 700 ml of profile D 'Angle, because the outgoing angles of the building are also treated as a hollow joint, ”pushes Alexandre Pierre. Parexlanko technicians thus support the Antunes company, in charge of the facades, for its realization. The prototype must also make it possible to stall the phasing of the work and in particular the application of the three types of coatings inducing layout issues. Finally, it turns out to be useful for validating the aesthetic rendering in real conditions. "We had some apprehensions about the appearance of the facades, potentially non -homogeneous if the projections of crushed marble had been unequal," explains Charlotte Brussieux. But, in the end, the rendering evokes more a system of cladding panels than a coating on it. What reassure the project management team, as much as the municipal town planning services, who came to inspect the holding of crushed marble and its adequacy with the local urban plan. On the site, the company simply devastated to the roadmap by adopting a mode of groove of the more practical insulation, obtained either by cutting over hot wire, or by assembly of blocks of different thicknesses to form the groove.
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