To explore the potential for lightweight solutions we use the doll house scale of 1:12, which is based on one inch representing one foot in Anglo-Saxon measurements. The advantage is that you are likely to run into real technical problems, which will be similar to the kind you will have to solve in the full size project. The availability of matching doll furniture in toy shops is a bonus.
A model this size provides insight. Simultaneously it serves to illustrate in which direction thoughts are developing. Every detail holds two contexts: the one about parts that need further research and elaboration, and the one about an impression of the actual design and construction, which is separately established in models to explore and test working principles.
Terraced houses, with closed sides, are the family to which the lightweight house will belong. The reason for this is that the design will look reasonably familiar to an audience, in spite of the unusual considerations behind the structure. It will show that it is supposed to be a normal house and no tent, or hut, or castle in the air, or some architectural statement. Principles of lightweight construction in a terraced house will lead to new propositions that are expected to be applicable in the development of all kinds of other house and building types.
Material reduction implies optimum distribution of stress. Favouring tension stress, as brought forward by
Buckminster Fuller, implies that the main enclosing body of the house does not stand on the ground, but is suspended from a horizontal structure that is supported by wide thin walled columns that take up the inevitable pressure. These columns could be made of rolled steel, or composites of wound fibres. A composite structure could be given a more appropriate form for withstanding buckling. Appropriate forming is the most obvious way to save material. The doll house model has got six columns, simple steel pipes. Less of those would have needed a larger circumference; when there are more they can each be narrower. In this stage an intuitive choice of six is sufficient.
To stabilize the columns horizontally they need a mutual cross connection. In the model this is achieved with tensegrity. A lightweight, possibly hollow, thick beam – to provide the cross connection – is fitted between pairs of columns, without any screws or rivets. They would damage the thin column walls. Instead each beam is clamped between the columns by spanning a tension belt around these, resulting in the near absence of a bending load.
The vertical column structure supports two horizontal beams, that could for example consist of wood and foam. Inflatable beams are another option. These could also contain or support a gutter for rain drainage. For watery details like this we have to be aware that the lightweight house is positioned right next to other houses, with their own drainage systems.
From the beams side walls will hang. They consist of woven cloth, fixed along the entire edge, to equally distribute forces along the beams. There could be a number of segments to be able to remove wall parts and replace or repair, or even just clean them.
In the model the textile walls contain off the shelf foam plate insulation. In 1:1 reality, insulation can be a matter of spraying foam into panels (measuring in the range of 2.5 x 3 metres) that either consist of 3D woven or knit fabric, or of simple stitched covers that define the shape. We have been experimenting with PUR in spray cans, which is difficult to control for this particular application. It could work with industrial processes. Foams offer manifold options. A new idea may be the kind of ‘foaming wood’ that Marjan van Aubel has been using in her ‘Well-proven chair’. When defining form textile has an important advantage: no expensive 3D mould is required.
Avoiding the need for 3D moulds by using 2D fabrics should be common sense. It saves tool making costs and is an interesting research requirement. Textile parts can easily be cut in 2D and consequentially translated into 3D forms. Mankind has been doing that for ages – look at the clothing industry.
In their turn 2D shapes can relatively simply be defined in algorithms that control cutting machines. It is possible to build a modular system that is not defined in ‘hard’ material proportions, but rather in software, thereby rendering the outcome much more variable.
1 In architecture there is a direction of styling based on choosing parameters in algorithms. It is known as ‘parametric architecture’. Recently deceased Zaha Hadid is an outstanding example of a parametricist architect. The parameters that architects pick to define form tend to be limited to those that are considered to influence a certain idea of visual aesthetics and architectural program and function.
In engineering parameters are used to establish production methods, make stiffness estimations, determine distribution of fasteners, control sound dampening, insulation, material use, buckling, thermal warp and many other properties that can be optimized together.
2 Currently 3D printing is making its way into daily practice. It has potential, but it also is a fashionable and rather overrated process. Both the required and the produced material quality are all too often disregarded, which may be caused by the seductive magic of seeing a simple device slowly spitting out actual objects from nothing. The main advantage of 3D-printing is adaptability through parameter variation. It is quickly becoming indispensable in the world of medicine (prosthetics) and prototyping. The main disadvantage is its slowness and uselessness for unprintable properties, such as the specific mattress quality you get by spraying foam into stitched fabric. The technology will continue to improve, but there will always be limitations.
From the wall segments, in their turn, horizontal beams are suspended, similar to the upper ones. They serve as floor supports. In addition, the walls of the story beneath are suspended from them. A floor consists of blocks of Styrofoam (or a similar airy material). Each panel will have a bottom with a catenary form, to match a band of textile that supports it, again to equally distribute stress over the width of the floor. Consequentially over its length a floor from underneath will look a bit link like an airplane wing hanging through the house, front to back. The textile slings, in which it hangs, can serve to attach lighting elements.
The top of the floor is flat and hollow, covered with hatches all the way. Cables, pipes and ducts are accessible everywhere because of this. They are not structural parts and therefore can be excluded from the construction process. In common ‘construction culture’ piping systems are always the bottleneck. They cause workers to have to stop working and wait ‘until the others are ready’. Here, inhabitants can change the whereabouts of pipes at will, anytime. Continuous easy access to the house’s infrastructure contributes to its proposition as a convenient user object. The system of access is refined by guiding cables and pipes vertically along the columns. Connections to networks (sewer, water, heat, energy, information) are situated at ground level.
In the model two floors hang below one another. At the bottom the ground floor connects directly to the street. It could provide space for vehicles and there could be storage, for instance for bicycles, tools, and garden equipment. To close the space one can think of curtains made of leopard print canvas, a classic decoration, a different façade, or more or less fashionable prints. If the opening needs to be vandal proof, canvas will probably be not strong enough. Other lightweight options need to be considered.
Control devices for climate, lighting, etcetera, could also be located there, but they could also be placed directly underneath the roof, or be distributed across the whole house. After all technology is programmed to gradually disappear.