Traditional Construction for a Sustainable Future

Carole Ryan

• Publisher: Routledge
• Year: 2011
• ISBN:
  9781134034611
• Edition: 1
• Topic: Arquitectura
• Subtopic: Arquitectura general

Since the spread of classical design and construction amongst the upper echolons of British society in the late seventeenth century, traditional construction methods have largely fallen by the wayside. Centuries later, as the construction industry faces up to its environmental responsibilities, this book explores its rich and ancient tradition to provide tried and trusted solutions to modern day construction problems.

By way of introduction, the ancient and historical lifestyles that dictated the nature of traditional construction are explored, before focussing on its health and ecological benefits. As well as cultural background, this book includes a detailed scientific description of traditional building materials and their constituents which draws a sharp contrast with modern petrochemical-based materials. The studies of traditional buildings included reveal the sustainability of features such as natural ventilation and breathing walls, and comparisons with modern construction methods show how they could prevent 'sick building syndrome'. The author argues that maintenance for long life, by contrast with the modern concept of life-cycle costing, is at the nub of sustainability and underlies the contribution traditional building construction can make to tackling climate change.

Over 250 original photos, and over fifty bespoke diagrams illustrate the features, techniques, and characteristics of traditional construction that could make such a valuable contribution to the industry today. The inclusion of a close study of how these methods relate to British building regulations makes this book a practical guide for construction professionals, as well as an authoritative resource for students and policy-makers.

1

THE NATURAL WAY OF LIFE AND THE TRADITIONAL HOUSE, ITS INCEPTION AND DEMISE

Ancient lifestyles and the use of natural materials

The meaning of vernacular/traditional

Vernacular building tradition is one based upon time-immemorial building techniques and the use of natural materials, but also upon the siting and location of buildings, the layout of their rooms, and room usage. It is passed on by word of mouth, and materials are used that are close to hand and do not require to be moved any appreciable distance. In addition its very essence is a format devised by the craftsman and occupier, acting in conjunction, and with function only in mind. Vernacular or traditional building is thus a response to a way of life, usually farming, passed on from generation to generation. That farming is now described as an industry is a very telling factor, as this way of life, still evident to our grandparents, has declined and with it the need for the buildings that catered for it.

Early lifestyles and shelters

Such vernacular buildings may have their origin in primitive buildings defined as temporary and constructed in flimsy materials. Today primitive buildings are hard to find, the most recent that may survive include farm buildings constructed of sawn-down telegraph poles and clad in corrugated iron, a product of post-war Britain, when both skilled men and materials were scarce. No one can be entirely sure exactly how ancient man adapted natural materials to primitive shelters as the pre-emptor of this vernacular tradition, as such materials were by their very nature ephemeral, apart from rock shelters. Cave dwellings certainly provided a solid basis for shelter, and had the advantage of a temperature that was cool in summer and warmer in winter.

Photo 1.1 A group of Herefordshire farm buildings indicative of a former way of life

Give anyone an instruction to go into the forest and make a shelter and one can be sure that it will involve cutting equally sized timber poles, placing them in the ground in a circle or two lines, and tying them with vines at the summit. The cladding of this tent-like structure is then a matter of what is available, be it large leaves or bundles of organic material such as leaves or straw. The translation of this into the cruck frame of the earliest surviving houses, some of which bear more than a passing resemblance, being mostly roof and not wall, is a matter of pure speculation. The fact remains that this continued into historic periods with the shielings (summer camp for grazing) of Jura, Scotland, with branches of trees covered with turf in a tepee-like shape, reinforces the possible theory. So does the beehive hut discussed below (the Skellig Islands, County Kerry, Ireland), although these tent-like structures are expressed in stone, the forerunner of mass walling construction. The few remaining black houses of the Isle of Lewis have roofs constructed of branches clad with turf in a linear tent-like form, on stone walls packed with earth. They are the latest and most tangible reminder of tent-like structures, being mostly 18th and 19th century in date. Excavated examples are rare, possibly because they consisted entirely of a wooden branch frame clad with turf that rapidly returned to the soil when occupation ceased. All these examples are reminiscent of a tent-like precursor.

Another parallel tradition which has a very ancient origin can be seen in the presence of lintel and post structures in chambered tombs (dolmens) to be seen in great numbers in Malta but also in the British Isles, and even the structure of Stonehenge hints at this form of construction.

The post and lintel is the basis of the possible classical tradition of the ancient world of Greece. There many theories on the origin and reason for Stonehenge, but few dwell on the possibility of two ring beam structures, one inside the other, of post and lintel format. The inner ring beam is higher, surely hinting at a possible use as a support for a hefty tree-like series of rafters, tied at the apex; in essence a giant megalithic tent. In some archaeological quarters such theories would be regarded as heresy, but the possibility cannot be discounted.

Photo 1.2 A rock shelter for animals on the island of Malta

Photo 1.3 Remains of a megalithic chambered tomb in Malta

Diagram 1.1 Stonehenge, conjectural reconstruction (after Fletcher, 1921)

The influence of climate

Climate must have been the greatest factor influencing the development of buildings, and has a bearing also on the quality and productivity of their environment. Physiological and psychological tolerance by humans to extreme heat or cold and the capacity of the same to affect the ecology, particularly vegetation and other animals, would have determined the vernacular architectural response to shelter. The use of vines for binding timber, the quality of the timber itself which determines how it can be modified, and the nature of animal skins for possible cladding or roofs and walls, will all be determined by the effect of climate upon environment. An even greater influence of climate is on the roof form of buildings. Roofs need to respond to temperature, solar radiation, precipitation and winds. Steep roof slopes are used in wet-temperate and cooler zones, the most prime examples being surviving British farmhouses with long low sloping roofs facing down a valley, encouraging run-off long before water can reach the walls.

Diagram 1.2 Primitive shelters (adapted from Fletcher, 1921)

Photo 1.4 Long, low, sloping thatched roof deliberately contrived to protect the rest of the building from adverse weather conditions.

Hot dry zones, in comparison, utilise flat roofs that can be constructed in considerable depth to absorb the sun’s rays long before the heat reaches the dwelling beneath. A more graphic reason why flat roofs are unsuitable for the British climate would be difficult to find, and yet they were constructed in great numbers in the post-Second World War period, indicating a loss of knowledge of traditional forms. In some cultures domed roofs were utilised to reflect the day’s heat back into the night sky, because of their greater surface area, but this does not explain the format of the 5th-century early Christian huts on the Skelligs (Irish coastal islands, County Kerry) with their corbelled roofs. In this inhospitable location, the roof form may well be an idea imported from warmer climes, or simply a response to the only material being available. The naturally shaly rock would lend itself to forming a roof by corbelling inwards until the apex was reached.

Photo 1.5 Corbelled huts on the Skellig Islands

Climate certainly affects design for comfort levels in buildings, although it has to be remembered that our own comfort levels contrast greatly with those of our immediate ancestors, a factor that is rarely taken into account by most recent occupants of vernacular buildings. The builders of these were more intent on creating shelters from extremes of climate and a shelter for the fire, and their occupiers were content to endure greater contrasts between heat and cold then we are. They also placed reliance on clothing that functioned both internally and externally, with little differentiation. That the fireplace was essential for air quality was possibly recognised, but in general, ventilation and day lighting was rarely addressed. The former was catered for naturally by the many draughts, and in the choice of porous materials for wall and roof, the latter must have been more difficult unless tasks could be directly illuminated by the fire. Domestic tasks, often large scale and dirty, had more credence out of doors in natural light, but the British climate would certainly have militated against doing so. A good example of this is the Dorset covered rear loggia or shire, known to have housed a multitude of dirty tasks. Unfortunately these rarely survive, having fallen victim to the modern desire for a conservatory in this south-facing location, but its original format was doubtless originally designed to capture light and solar gain.

The nature of traditional construction demanded small openings for stability and the need to retain heat, the walls acting as a thermal store, so they did not allow for large windows. Conversely it is interesting to note that even until recent periods, elderly farmer’s wives pursued their domestic tasks with the kitchen door wide open, even on the coldest day. Such a way of life would be unthinkable now. Another factor that characterises traditional buildings is the lime-washing of both interiors and exteriors. Widely thought to have its origins in the use of lime as a disinfectant and inhibitor of woodworm and fungal decay by virtue of its strong alkaline chemistry, the white interiors would have helped to reflect light to militate against the use of small windows. The external white coating would have kept the house cooler in summer, building up to a fine plaster to protect the masonry and joints, although the practice would have provided no solar gain in the depths of winter.

It is interesting to note that mass walling construction, which has its origin in the need to provide thick walls for stability, also results in walls that are capable of operating the thermal flywheel effect. The building is warm in winter, as the internal surfaces absorb the heat from the fire, reflecting it out when the fire dies down, but also keep buildings cool in summer by resisting the penetration of the sun’s rays. It is known that walls need to be a minimum of 250 mm (10 in) to provide an eight-hour thermal lag (Oliver 1997a: 132), and walls in most 16th- or 17th-century farmhouses are at least 500 mm (20 in) and in some cases considerably more.

Photo 1.6 A partially underbuilt Dorset shire for undertaking unpleasant tasks beneath its shelter

The location factor

The location of a farmhouse, in respect of its immediate landscape, is rarely examined today when making a decision to purchase (apart from a nice view), yet our ancestors would have taken many factors into account before deciding to build. The drainage of the ground would have been a key element, plus the presence of a shelter belt of trees, essential in mitigating wind-chill factor. Sadly the first thing that most recent occupiers do is to modify this landscape so that features like this are removed, because they block the view, giving little thought to the value of these trees not only in winter, but in providing essential shade for summer. By the same token the availability of water, a river or brook, was not only essential for human and animal life, but the amount of it falling from the sky, be it great or small, also determined the nature of the shelter. In areas where water is frozen, both the extreme cold and the difficulty of obtaining water will act together to deter settlement. The topography of the landscape also will determine the ease with which settlement can take place, particularly orientation.

Lowland areas, defined as lying at less than 300 m (1,000 ft) above sea level, and rich in vegetation, would always have been attractive to settlement and the vegetation itself a natural source of material for shelter. Upland zones and higher slopes, always more inhospitable in terms of access and materials for shelter, have traditionally been more sparsely populated except in times of war or stress, such as over-population of the lowland zone. Not withstanding this there were advantages, such as ease of defence, avoidance of disease, proximity to pastures, and land availability away from the crowded lowlands for poorer people. In addition, in warmer climes hilltop locations were more comfortable, being cooler in summer, but the British climate demands a hardier breed of occupant altogether. Hilltop towns, such as Bridgnorth in Shropshire, hint at more defensive reasons, and in all events are outcrops in a more lowland plain. It is interesting to note the connection between this form of settlement and the earliest rock shelters. The cellars of hilltop towns, hewn out of the rock, may have provided the material for the rest of the dwelling. Also the void between the inclined hillside and the floor of the main dwelling provided an area for cold storage, taking full advantage of the thermal flywheel effect. In some instances the cut-outs in the rock were dwellings themselves, and until peremptorily closed by the Public Health Acts in the post-war period undoubtedly enjoyed all the advantages of being cool in summer and warm in winter. It is noticeable that the need for shelter from wind, as well as the need for warmth, encouraged the clustering together of dwellings. Deep eaves and sheltered balconies are the rule in more exotic locations such as Malta, providing shelter from winter storms and summer sun.

Photo 1.7 A Mediterranean style farmhouse designed to cope with very hot weather

In British uplands there is more dispersal of settlement and ancient patterns in construction, but more pertinently a continuum in traditional lifestyle and customs, still visible today. This may be due to the slow change discouraged by difficulties of actual access and communication with other settlements. The south Shropshire Hills is an example where until quite recently one could still see a pastoral farming economy and a way of life unaltered by the passage of time.

The intimate connection with green spaces and the eventual loss of contact between man and nature

Settlement then is an essential part of what governed the nature and form of dwellings, but how did this settlement arise? At best it can be regarded as the colonisation of what started as vast tracts of forest covering large...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• Acknowledgements
• 1 The natural way of life and the traditional house, its inception and demise
• 2 Traditional building materials, their sustainability, and the contrast with modern materials
• 3 Traditional sustainable building construction - ancient and modern
• 4 Thermal performance and the breathing wall
• 5 Climate, site, and thermal performance
• 6 The role of the Building Regulations in the sustainability of traditional building construction
• 7 The pathology of traditional buildings
• Bibliography
• Index