Sawhorse House

Sawhorse House

Alejandro Soffia, Arquitecto
La Reina, Santiago, Chile
Project Year
Private Houses
Juan Durán Sierralta

Sawhorse House

Alejandro Soffia, Arquitecto as Architects

This is a refurbishment of an Economic House designed by Arturo Urzúa and Federica Frank in the decade of the 60’s. The project recognizes the interesting and pragmatic pre-existing structural system, and mades a new lecture of it to support, as a Sawhorse, a new completely different second floor with SIP panels.

Personal Matters I am interested in getting away from certain perceptions that our society has, justifiably, about some practices of our discipline. Many people think architecture is expensive, rigid, and even lustful. It`s difficult to understand that many works pursue aesthetic aims - many times ingenuous - subjecting posterity to the constructive process. In these cases the order of the factors did alters the product, making the projects more complex, and above all unnecessarily expensive. What fault does the owner have to pay this surcharge? And many times he does not even know…

I prefer to start working with the simplicity of construction materials, which allow us to create an imaginary of neutrality and efficiency. If a responsibility for design is to define our aesthetic relationship with the world, clinging to the properties of the materials allows the works of architecture to express themselves in a transparent, optimal way, facilitating their accessibility. Based on these ideas I faced my projects with prefabrication strategies (SIP Panel Houses) and simple technologies (Hostal Ritoque, Polycarbonate Cabin). Due to the preexistence of Casa Caballete, without neglecting these ways of achieving a high quality design at low cost, I have also sought to leave only the necessary, stripping the project of the unnecessary, especially linking with the structure. The structural elements are those that must be constructed from the beginning and also should be essential. I am interested in this sense in the structural analysis of the morphology of organisms already developed, where their structural elements seemed to be the just and necessary to fulfill their vital functions.

Home of Federica Frank and Arturo Urzúa The project was to transform a preexisting social housing of a single floor in two. It is a repeatable unit within a condominium complex, along a passageway, one of the urbanization models typical of “La Reina” District in Santiago. The lot is legally protected under the figure of a Cooperative, a social organization that allowed to buy between several people a small cloth of land and to subdivide it, in addition to opting for soft loans from the State. The set of 20 houses of the "Rapa Nui" Cooperative has only one type of dwelling, and has two simple operations in its repetition. The first consists of being attached to one of the dividing lines of property, and the second to alternate in a short and a long measure to the building line

The house itself has a square floor composed of an reinforced masonry ring and an interior distribution of partitions around a central hallway. The aisle is defined in its four vertices by 4 x 4 "wooden pillars, which in turn respectively support 4 rafters that meet each other in the transversal axis of the house

which allows to construct it the corners by squaring, without having to use concrete pillars. However more or less in the center of each wall, where the structural deformation is greater in this type of corner structures, a concrete pillar of 20 x 40 cm is placed, and transversally to the wall to be more efficient from the structural point of view

Over these rafters are wooden joists, ceiling joists and roof sheets. The masonry ring is reinforced since it uses structural industrial bricks of 17.5 x 24 cm

Thus, in the manner of a buttress, it holds a chain of concrete that finally crowns the system. The windows go from floor to ceiling, with small light walls when they don’t fill the bay. The parquet flooring would perhaps give it a “Kahnian” material contrast in its origins, dialoguing in a patagonian austerity between eucalyptus, cement and clay.

Housing of Johanna Whittle and Daniel Morales The family that would inhabit the new house was more on sharing in a large common space, than to segment the various daily activities in individual spaces. Therefore I wanted a large space where the collective acts of the house, such as cooking, eating and living, would be related. Given the efficient distribution of the original plant, it was easy to accommodate that large space on a new single floor, and to leave the other for all the individual uses like sleeping and bathrooms. Then it was thought - of course - to completely release the first floor to house the large common space, and leave the bedrooms upstairs. So when you access the home one would find the public space away from the intimate space in the second. In addition one would have a perfect relationship with the patio. However, given the narrowness of the terrain, and the imposing presence of the Andes Mountains, the second floor would have a higher quality spatiality. Therefore it was decided to invert the program, leaving the bedrooms on the first floor and the large common space in the second. To access the second floor would maintain a core of central circulation, and originally a second staircase that would link the large space with the patio to facilitate accessibility . However for reasons of budget, it was decided to eliminate this second staircase.

The volume of the second floor is strongly determined by normative aspects. From the outset the first floor plan was not possible to extrude vertically to a second. Therefore we had to distance from the southern dividin limit, also without possible sight by its proximity with it`s neighbor. On the opposite side, because of the north neighbor's adjoining, the volume of the second floor could advance in this way, but only until it meets the angle of “adosamiento”, that unfolds in 45º from a height of 3.5 m from the level of natural level

Therefore, although the volume of the second floor was dipped as an orthogonal prism outdated in relation to the first, in the development of its height was taking the form of a double slope roof. According to the regulations described, both north and south walls could not have windows. West wall lead to the passage, and added to the radiation in summer, we preferred to maintain it only with a punctual window. Thus the main window gives to the east and coincides with the view to the Andes Range. Finally, to recover the constant and direct presence of the sun, we opened a lucarna stretched all the length of the longitudinal axis of the house

To structure the volume of the second floor it was considered the same strategy of the preexisting housing, supporting the roof by horizontal pieces that were supported in this last case by vertical elements. The new sawhorse respects the composition, location and orientation of the original, but replaces the wooden structure with steel tubular pillars 135 x 135 x 5 mm and double C beams 200 x 50 x 5 mm

The new structure allows the support of the mezzanine and the inclined planes of the roof. It also lodges inside the staircase

The rest of the structure is through the walls supporting both the second and the first floor. The mezzanine is made up of SIP panels of 210 mm thickness, and the volume of the second floor, both walls and roof with panels 110 mm thick

The dimensions of this are determined by the unit multiplication of the width of the panels (122 cm). In this way the project is subject to both the logics of prefabrication and material optimization.

The volume of the second floor is finished by structuring with a ring of walls in panels, the presence of a core of bathroom and two diagonals on the only open side

Finally, during the process of building the system, it aroses the concern to strengthen lateral resistance. In this way appears a last constructive element, that through the stiffening of the sawhorse in its upper part, strengthens the meeting of the four main pillars of the house.

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