Chapter 6: Material Procurement, Production and Use
6.4 WERE CHANGES IN ARCHITECTURE A RESULT OF NEW MATERIALS?
As discussed in the preceding chapters (see section 2.3), building materials have been an essential component of the argument for a timber-to-stone transition and for an evolutionary progression of architecture in Etruria. Focus on a supposed, seventh- and early sixth- centuries BC material transition produced a view where superior materials replaced inferior ones. Not only considered a witness of the domestic architectural changes in this period, the transition from inadequate to viable also prevails as the primary reason for all architectural changes. According to some archaeologists, such as Torelli (1985) and Ridgway (1988), as well as Pallottino (1975) before them,
464 conscious decisions on material choice, made throughout central Italy, triggered the architectural changes purportedly recognised archaeologically. Accordingly, the intentional choices of superior construction materials altered the domestic architectural fabric, allowing for greater diversity in architectural design.
Based on research into the adoption of new technology, it is unclear how much the changes in manufactured material production and use resulted from a choice of material superiority. This is especially evident in the Etruscan archaeological record. Traditional manufactured building materials from the eighth century and earlier (such as timber and wattle) are still as significant in the sixth century as they had been in the eighth.
However, those who see the appearance of new architectural styles as part of an evolutionary progression base their arguments on the notion that superior materials triumphed over inferior materials in due course.
Based on recent studies of traditional building materials, even this assumption, where new manufactured materials were a superior choice, is untenable.
Nowhere is the superiority of one manufactured building material over another clearer than in the advantages of timber-built over stone- built structures in earthquake prone regions. A number of case studies in Turkey and Greece note that stone, steel and concrete structures fail more often following seismic events than their timber counterparts (Doğangün et al. 2006; Gülkan and Langenbach 2004; Langenbach 2003;
465 Makarios and Demosthenous 2006). While timber structures were by no means safe from damage, their overall elasticity and stress resistance prevented collapse at a much more significant rate than buildings without a timber frame.
The advantages of timber built structures in central Italy are apparent in the archaeological evidence, too. Demonstrable damage to ashlar tufa stone has been found at San Giovenale (Blomé and Nylander 2001; Nylander 2013:138-142). This damage attests to the 550/530 BC earthquake that struck southern Etruria. These seismic events are blamed for the roof fall of House II in Area F East, in particular, as well as the destruction of many of the other houses at the Borgo and the acropolis (Blomé and Nylander 2001; Karlsson 2006:163-164; Nylander 2013:138-142; Pohl 2009:20-21). As many modern structural engineers now realise, it is clear that extensive use of ashlar masonry and possibly also terracotta would have been less architecturally sound in an earthquake than the traditional manufactured materials (Langenbach 2003; Vasconcelos et al. 2013).
On top of the seismic analyses, a number of engineering articles indicate the weaknesses of historical, self-supporting ashlar walls to vertical compression stress and shear stresses (Foti 2013; Lourenỗo 1998;
Valluzzi 2007; Vasconcelos et al. 2013). In comparison, timber-built structures are more likely to withstand these pressures (Vasconcelos et al. 2013). Subsequently, systems of internal worked timber beams and
466 posts have been widely suggested for reinforcement in building conservation of stone-built structures (Valluzzi 2007; Vasconcelos et al.
2013).
Thatch, too, should be seen as an equally suitable, if not superior, roofing material to terracotta tiling, particularly in the seventh century.
With clay waterproofing and consistent maintenance, thatching can survive intact for upwards of a century in some cases (Hall 1982:23).
Although by no means a light material, thatch is also significantly lighter than terracotta, making for less vertical compression stress on the walls and therefore greater structural stability (Damgaard Andersen 2001:255;
ệ. Wikander 1993:162). If kept dry, then thatch is essentially watertight and rot free, especially when clay-revetted (Fenton and Walker 1982:69;
ệ. Wikander 1990).
Flammability is the main problem with thatch and the only truly superior aspect of terracotta. Since it must be kept dry, interior heat (i.e.
through hearth fire and smoke) must be maintained (Ley 1995:5; ệ.
Wikander 1990). Although slightly less-flammable when clay revetment is added, the dangers of flammability are omnipresent in thatched buildings (Ley 1995; ệ. Wikander 1990; 1993:161-162). Archaeological evidence supports the known flammability of thatch, with destruction events by fire evident in the Iron Age buildings on the acropolis at San Giovenale (Karlsson 2006:137-142). However, buildings with tile roofs
467 were not safe from fire either, as seen in the destruction of the Southeast Building at Poggio Civitate (Tuck and Nielsen 2001; 2008).
ệ. Wikander (1990:289) suggests that the vulnerabilities of thatch might be a possible cause for the widespread adoption of terracotta.
Rather than arguing that terracotta was somehow a more permanent (e.g. Steingrọber 2001:20, 26) or desirable (e.g. Izzet 2007:153-154) manufactured material, he proposes that increased urbanisation created the driving motivator for the change in manufactured roofing materials.
Due to the known flammability of thatch and the increasing density of settlements starting at the end of the eighth century, ệ. Wikander (1990:289) contends that, by the late seventh century, fire in a single domicile was no longer limited to that domicile but was instead a threat to the community. Starting with temples (the most culturally valuable or, at least, expensively produced structures), he suggests that by the sixth century, urban buildings had adopted terracotta not because it was more permanent or visually appealing but because it was safer in the new, urban environment.
This alternative motivation for changing production and use of manufactured materials is illustrative of possible influences besides technological superiority in the appearance of terracotta roof tiles in the seventh century BC and their subsequent widespread use. Urbanism, as argued in a sense by Steingrọber (2001) and Gros and Torelli (1988), in fact played a crucial, formative part in changing production and use of
468 manufactured building materials but it is not based on material superiority. Instead, the economic and social changes of urban environments led to the adoption of materials that were not superior to the traditional materials in themselves but better suited to changing residential contexts.
Even with the appearance of terracotta tiling, many traditional (and also in some ways technically efficient manufactured materials), namely timber, wattle and mud brick remain the primary manufactured materials used in buildings from 800-500 BC. Therefore, despite all the changes to manufactured materials brought on by urbanisation, use remains relatively constant. What changed appears to have been the methods of production. By the late seventh century, the production of manufactured materials was no longer a domestic affair but was instead conducted by specialists. Shifting production of manufactured building materials fits well with the wider literature on manufactured ceramics and metals (Nijboer 1997, 1998, 2006; see Chapter 7). This change in production altered the use of manufactured materials, where increased standardisation and quantity became the norm by the sixth century.