Chapter 6: Material Procurement, Production and Use
6.1 THE DIFFERENCE BETWEEN BUILDING MATERIALS AND BUILDING
In discussions of architecture, the term ‘building material’ is often used as a catchall, representing components of a structure in an imprecise fashion (e.g. Becker 2014:11; Donati 2000:317-321; Edlund- Berry 2013:700). While not necessarily problematic when a simple description is the goal, if the term is used in descriptive reconstruction without specific reference to its context, then the result of the analysis can be as imprecise as the initial description. Such analyses can lead to sweeping conclusions about material procurement, production and use that are ultimately untenable and, more often than not, confusing (e.g.
descriptions of graticcio; Camporeale 1985:129-130; Donati 1994:33, 93;
Nylander 1986; Wendt 1986; see Chapter 5). Contextualising the term
‘building material’ by classifying the types of building materials in analysis is crucial and often overlooked in the discussion of architectural features.
Generally, structural engineers split the description of building materials into two broad types: raw and manufactured materials (Ward- Harvey 2009:1-2; see Glossary). The first type, ‘raw materials’, represents the unprocessed elements of structural components. The other type,
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‘manufactured materials’, represents the synthetic (i.e. manmade) parts of a structure. Although separate terms, these material types are representative of processes and are therefore not mutually exclusive, considering that manufactured materials are produced from raw materials.
The application of such terminology can be observed in the description of an ashlar block of tufa stone. Describing the block as a raw material recognises in the first place its composition (tufa stone) and also, to varying levels of accuracy, its provenance (a specific tufa source). In contrast, describing the block as a manufactured material qualifies it by its process of manufacture (carved ashlar masonry). Identifying its manufacture establishes that, in contrast with other manufactured materials comprised of stone, an ashlar block is both physically and conceptually different.
Failing to acknowledge the distinction between the two terminological types can lead to a confusion of building materials with building techniques. A building technique is the practical use of a material (be it a raw or a manufactured material) in a structure (OED Online 2009). Since they are not raw materials, without the specific classification of ‘manufactured materials’, manufactured materials can be (and have been) mistaken for building techniques and vice versa (as seen in more detail in the next section). For instance, wattle is a manufactured material comprised of the raw materials cane (Arundo donax) and wood.
409 It should be considered a manufactured material because it has a discernible crafting process and although it is most often used in walling, its use in construction is not defined by its manufacture. The process of using that wattle as a specific component in the construction of a structure is a building technique. Therefore, the wattle walling technique is a separate process from wattle as a manufactured material, even though that distinction is not often realised in the literature.
In contrast, half-timbering is not a manufactured material. Rather, half-timbering is a building technique that describes the use of certain manufactured materials in the process of construction. Those manufactured materials are produced in independent processes from the construction itself and are, namely, shaped timber beams and posts as well as an infilling, such as wattle or mud brick. While these manufactured materials are made for an explicit purpose (i.e. to be used in walling), they themselves are the product of a completed operational sequence, to be used within a wholly separate operation (i.e. in conjunction with other products in a building technique).
Furthermore, not allowing for a distinction between material type and technique has played a major part in the confusing combination of wattle and half-timbering in the literature. Recognition of half-timbering as a building technique is common, such as Nylander’s (1986:56) and Wendt’s (1986:59) descriptions of San Giovenale and Acquarossa, respectively. Yet, their inclusion of wattle in the description of half-
410 timbering is confusing because there is a failure to identify wattle as a separate manufactured material used in the half-timbering technique.
Instead, when describing the infill of the half-timber frame, many refer to the make-up of the infill (the raw materials) rather than the wattle or mud brick (the manufactured materials) used in the half-timbered structures (e.g. Bartoloni 2012:266-267, 274; Nylander 1986:56; Wendt 1986:59). By not realising the distinction between the raw and manufactured materials, the half-timbering appears as though it were a manufactured material itself as opposed to a way of using building materials in a structure.
The distinctions between material types and between materials and techniques are therefore critical because they decouple procurement from production and production from construction. Vagueness in discussion leads to confusion in interpretive analysis, as seen in the presentation of the supposed, seventh and sixth centuries BC transition in building materials. Steingrọber’s (2001) account of Etruscan architectural change is a good example of the confusion. He states that,
“the definite transition from the hut to the rectangular house, from transitory to more solid structures and materials including new building techniques (roof terracottas, opus craticium, clay bricks, walls with stone pillars) took place” (Steingrọber 2001:26). The conflation of “structures and materials” with “building techniques” is unspecific. Does Steingrọber think that the availability of new building materials drove the transition
411 to permanent structures or that the transition to permanent structures forced the adoption of new materials? The “new building techniques”
certainly seem to result from the use of “more solid structures and materials” but what Steingrọber identifies as material and what he identifies as a building technique is unclear given his addition of “roof terracottas” and “clay bricks” along with his list of building techniques.
His use of “clay bricks” reveals the confusion of terms particularly well. Mud bricks are manufactured materials made of the raw materials soil, water and straw (Genovesi 2001:315; Rael 2009:112-115). Only when the mud bricks are added together and used to construct a wall are they then a building technique. Without giving the descriptive value of the building technique (in this case ‘walling’), Steingrọber risks the conflation of the material mud brick with the technique mud brick walling.
The conflated terminology may have resulted from naming a building technique after the manufactured material that comprises it, as Steingrọber does above. As seen in the previous chapter, the associated naming of techniques has created a problematic focus on building materials, particularly in the discussion of walling. Via association, changes to techniques and even structural form are directly tied to the building materials of a structure. From this associative focus, any perceived change to building technique directly results from the materials they are associated with.
412 Building materials are basic elements in the discussion of architecture and it is therefore necessary to maintain clarity in terminology to prevent confusion in analysis. Splitting the discussion of materials into more clearly defined types dispels much of the confusion between procurement and production. The remaining confusion between manufactured material and building technique is less easily rid of.
However, with strict adherence to the accurate use of terminology and an awareness of the distinction of materials and techniques, the confusing combination of completely separate processes can be avoided. An example of the analytical clarity this recognition provides can be seen in forthcoming sections of this chapter.