optimising the use of unfired clay products in rural ... · optimising the use of unfired clay...

OPTIMISING THE USE OF UNFIRED CLAY PRODUCTS IN RURAL HOUSING: THE ROLE OFHOLISTIC EVALUATION

Fionn Stevenson 1Bruce Taylor2

Tom Morton3

1 School of Architecture, University of Dundee, 13 Perth Road, Dundee DD1 4HT, Scotland,[email protected]

2 Scott Sutherland School, The Robert Gordon University, Garthdee Road, Aberdeen AB10 7QB Scotland,[email protected]

3 Arc-architects, 69 Burnside, Auchtermuchty, Fife KY14 7AJ, Scotland, [email protected]

Keywords: unfired clay, sustainable housing, post occupancy evaluation, Scotland

SummaryUnfired clay has been promoted as an environmentally benign material which helps to optimise the heatingand humidity requirements for users through its particular properties. Although there has been muchphysical testing of the material there has been relatively little evaluation of it through case studies. Thispaper summarises a two year evaluation of an innovative house project in the Highlands of Scotland whichincorporates qualitative post occupancy evaluation as well as traditional physical monitoring and a carefulevaluation of the construction process. It presents a uniquely hybrid and holistic research methodologywhich successfully highlights some key issues for innovative design using unfired clay products as aresponsive envelope and which closes the rural resource loop. Strategies adopted by users can often becounterproductive to design intent unless all parties understand the interaction between building and user,which is always context and culture specific. A number of unanticipated outcomes were identified throughthe research which has informed future guidance. When all the results are taken together, the use of unfiredclay has clearly been beneficial from the residents point of view, and this has been corroborated by themonitoring exercise. The project also provides a replicable bioregional model for sustainable rural housingthat empowers the local community and sustains local identity through decentralised production.

1. The PlaceEast Dalguise is a small hamlet in the region of Perthshire half way up a North East facing hill in the middleof Scotland, lying at latitude of 56 degrees. It is essentially a rural place which demands a local approach tothe sustainable use of construction resources. The region is well endowed with natural constructionmaterials, containing fine woodland, granite and sandstone together with the finest alluvial clay in the UKalong the River Tay. For more processed materials, the only surviving local brickworks is 38 miles away, thenearest cement manufacturer is 95 miles away, and for steel and glass you would have to travel outside ofScotland. 60% of new build houses in the region are now energy intensive timber kits, with the majority oftheir timber imported from other countries and even the finished components traveling considerabledistances (Stewart Milne, 2003). They use virtually no local materials or products in their construction.The decline in rural small scale production industries for construction materials in Scotland has occurred atthe same time as a significant deskilling of the local construction workforce particularly in relation to joinery,bricklaying and masonry. The rise of global pre-fabrication means that local construction workersincreasingly rely on pre-made units, which they simply put together (Seaden, 2003). They often have noresource to “fix” these units when they fail for any reason during transportation or site assembly. The unitsare simply returned and repaired or replaced by a factory that is often hundreds of miles away.While much research is currently focused on reducing the urban ecological footprint, the rural use ofresources impacts upon the sustainability of the planet by stealth, largely through transportation and waste.Scotland has effectively run out of landfill sites to dump the waste from its single biggest non-domestic wastestream; construction waste (SEPA, 2003). At the same time, global warming has introduced the sharpimperative to reduce overheating in housing in the UK, with external temperatures predicted to rise by up toseven degrees in the latter part of this century (CIBSE 2005), while reducing energy use by 60% to preventany further deterioration of the climate (RCEP, 2000).A demonstration project in East Dalguise has engaged with these interrelated and complex issues andprovided not only a replicable model for sustainable rural housing that empowers the local community andsustains local identity, but also uses a uniquely holistic approach to its evaluation.

The 2005 World Sustainable Building Conference,Tokyo, 27-29 September 2005 (SB05Tokyo)

- 2565 -

09-008

2. The Project

2.1 Project BackgroundThe one and a half storey unfired clay-brick house was built using a mixture of government grant fundingand private finance, and completed in the Summer of 2003. The prospective residents acted as the maincontractors for the project, subcontracting most of the construction to local contractors and self-buildingsome elements, where possible, to keep costs down. The architects who designed the house wereparticularly interested in developing a sustainable, low cost and buildable rural housing model, and soughtgovernment research funding to develop and evaluate the project from the outset of the design process.

Figure 1 Ground floor plan of demonstration house at East Dalguise, Perthshire

The ground floor plan (Fig 1) shows the external walls which comprise of a load bearing timber frame withthe inner brick leaf of unfired clay brick finished with clay plaster. The cavity is filled with 200 mm celluloseinsulation and the external finish is local larch timber cladding. The ground floor is concrete slab coveredwith 120 mm dense polystyrene insulation on top of which is concrete screed with underfloor heating pipes.The finished floor is untreated oakwood. The slate finished roof contains 220 mm cellulose insulation and islined with plasterboard. The timber glazing is a modest 16% of the wall area. The roof area was deliberatelydesigned for future conversion to room-in-the-roof bedrooms and was quickly adapted for this use by theresidents within the first year of occupancy.The unfired clay bricks were developed by the local brickworks, who estimated that 40% of their productiondid not have to be fired for the uses they were put to and saw their wide potential for constructionapplications, as well as a welcome opportunity for diversification. Unfired bricks typically have 350 Kwh/m3compared with 1462 kWh/m3 for fired bricks, which represented a significant environmental benefit as wellas reduced manufacturing costs.When the brick is combined with the plaster, the inner leaf has 27 times the physical mass as conventionalplasterboard lining in timber frame construction. The unusual house construction, which reverses thetraditional construction of masonry outer skin and inner timber frame, allows the thermal mass to be fullyemployed as a potential “heat sink” for the house. This can help to even out the diurnal temperature swings(Roaf et al, 2001) that can be experienced in Scotland, even though it is at a relatively high latitude and hasa maritime climate. It also allows the unusual hygroscopic properties of unfired clay to be tested due to itscomplete exposure to the interior of the house.

2.2 The Research PlanThe primary focus of the research was on the use of the unfired clay bricks and clay plasters as aninnovative construction material in Scotland which could help to address the issues set out in Section 1. Theoverall aim was to see how these products and materials performed in practice compared to laboratorystandards, as well as to disseminate good practice through the lessons learnt.The evaluation of the project was carried out in seven stages:a) Buildability: ease of construction, adaptability to standard labour skills, site storage, waste management,health & safety issues, robustness through construction, assessed by site records, interviews andinspections.b) Durability: shrinkage, damage from abrasion & impacts, assessed by visual inspection.c) Thermal performance: field monitoring of temperatures through the wall at four key locations in theoccupied house, as well as heat flux at one of these locations, at 15 minute intervals over one year.


d) Relative Humidity performance: field monitoring of relative humidity through the wall at four key locationsin the occupied house, at 15 minute intervals over one year.e) Air-tightness: Whole house pressurization test after completion.f) Acoustic performance: testing the acoustic insulation experienced across the internal wall construction.g) Post Occupancy Evaluation: on site visits and telephone interviews with the residents and weekly logssheets recorded over one year, all of which were related to the other stages of evaluation.The monitoring for stages b), c), d) and g) spanned from November 2003 until November 2004. Over amillion points of data were generated for the thermal and moisture performance, with the electronic loggingequipment transmitting the data to a remote University via a telephone network. The results and analysisfrom the evaluative stages relate to the performance of both the house design and the unfired clay productsused, and, crucially, the interrelationships between these two elements and the residents. They aresummarized under the next three sections.

3. Construction Issues

3.1 BuildabilityThe bricklayers found the unfired clay bricks very easy to use and preferred them to fired bricks becausethey were kinder on the hands and much easier to cut. The plasterers found the clay plasters less dusty thangypsum, but heavier and slightly harder to work. They also experienced some difficulties initially in obtainingthe right finish, largely due to their complete inexperience of the working qualities of clay plasters. The self-finishing clay plasters do not lend themselves to a polished finish, which is what plasterers generally aim forwith the predominant gypsum plaster. The bricklayers needed no additional training to use the new productand were keen to use them again. However, training for plasterers will be vital to ensure the proper use ofclay plasters. These plasters also differ from commonly used gypsum plasters in that they set by dryingwhich takes more time. Clear guidance should be given to contractors on this so that the works can beefficiently planned.At the end of the construction period, although the majority of plaster joints remained sound, some cracksopened up at the head of the internal partitions, indicating differential settlement. There was some minorcracking on the surface of the plaster, primarily linked to differential substrates. Good practice and guidancecan minimise this problem. The residents also noticed that the clay plaster was taking “a number of knocks”compared to plasterboard, but were relatively unperturbed because the relative softness of the bricks andplaster enabled them to easily fill cracks and holes as necessary. A hidden benefit for the residents was thatthey felt able to “adjust” the walls by carving the window reveals to a more rounded shape. They found itvery easy to fix items to the walls, using the type of screws that are normally used for timber, without theneed for plastic or wooden plugs.The relative simplicity of the house construction and materials used has thus empowered the residents andgiven them a degree of confidence to carry out alterations and maintenance as necessary. In the long term,this will save considerable embodied energy as it allows the house to remain highly adaptable for manyyears.

3.2 Waste, Biodegradeability and Embodied EnergyThere was very little wastage from the plastering as any residual clay plaster could simply be reworked fromday to day. The wasted unfired bricks were simply redistributed over the site and left to disintegrate backinto the soil, being 100% biodegradeable and water soluble. As a result, there was no requirement todispose of waste offsite, and no unsightly brick spoil, which represents a real advantage for this product inrural situations. Its biodegredeability provides a very effective way of closing a resource loop both duringmanufacture and on site, without any additional processing or transportation. This can have significantadvantages over recycling and reclamation in rural areas, where either of these is inefficient due toexcessive transportation distances involved. This proved to be the case in this project, where themanufacturer deemed it uneconomic to transport the wasted bricks back to the factory for recycling.The unfired bricks are manufactured using a simple mechanical conveyor and continuous extrusion. Theyare air dried for approximately two days in large drying chambers which reduces the moisture content of thebricks to approximately 2%, and uses approximately 17% of the overall energy normally required to dry andkiln-fire the bricks at the same brickworks. The UK definition used to calculate their embodied energy istaken to be the amount of energy required to source, process, and transport the product to the site. It doesnot include their complete lifecycle in terms of their use in this and other buildings over time, as this is toounpredictable. The detailed calculations for the embodied energy involved in the unfired clay bricks for thisproject are described elsewhere (Stevenson, 2005a).In summary, 220kwh/m3 (146 KWh/tonne) compares favourably with previous embodied energy estimatesfor unfired clay brick, using nearly six times less energy than an ordinary brick. This is partly due to the


relatively low transport costs achieved through the use of a local product. Industrialised processes willalways require space-efficient drying chambers, which in turn will always require an energy input. It may bepossible, however, to use waste heat from the kilns to heat these in the future. This would give a distinctadvantage to having unfired and fired products manufactured side by side on the same site. Anotheropportunity for further reducing the embodied energy of the unfired clay brick is to use solar energy for pre-heating the incoming air of the drying chambers.

3.3 TransportationTransport is a critical issue in relation to resource use in rural areas. In the UK, we spend as much energy ontransporting our construction materials as we do making them in the first place (DETR, 2000). While urbanareas can mimic ecosystems and use industrial ecology to help minimise transportation, rural areas do nothave the critical mass for this type of dynamic industrial interaction and often depend on relatively longsupply chains spread over large distances in order to procure any sizeable building activity.Scotland, like many countries, has a concentrated urban sprawl where most of its industrial production takesplace and from which the vast bulk of construction resources is transported inefficiently along relatively poorroads. At the same time, there are virtually no rural depots either for locally reclaimed or recycled buildingproducts and materials, which means that demolition waste has to be transported further away. Thedevelopment of decentralised production for local construction materials such as clay, which can be eitherreturned to earth via its biodegradeability or easily reclaimed and recycled locally due to its relatively simplecomposition as a building element, is a key means of reducing transportation for rural construction over itsentire lifecycle (Berge, 2000).

3.4 A Bioregional Approach to MaterialityThe simple and limited palette of natural materials used on this project (unfired clay, slate, timber) togetherwith an appropriately limited use of more highly processed glass and concrete, makes the buildingconstruction relatively easy to understand and maintain by the rural user, who has “tacit knowledge” of thelocal vernacular from living in the area (Polanyi, 1966). Covering the clay bricks externally with timbercladding may be seen by some as a “dishonest” use of local materials (see figure 2), but historically unfiredclay usually had an external covering in Scotland, due to its relative vulnerability to the weather, and timberwas often used to clad buildings. There are popular misconceptions about stone being the predominanthistorical construction material for Scotland. In fact, timber and earth construction were more normal for ruralbuildings up until the 19th century, using local materials that were readily to hand (Davies et al, 2002).It is equally important, however, that these locally procured materials deliver a robust performance bothintrinsically and in relation to the house design. The next section describes how the local unfired clay bricksand the clay plaster performed over a range of tests and during extensive monitoring.

Figure 2 Illustration of demonstration house at East Dalguise, Perthshire after one year’s occupation


4. Physical Performance

4.1 Thermal PerformanceThe thermal performance of the unfired clay bricks and plaster, detailed elsewhere (Taylor, 2005a, Taylor etal, 2005), reveals their complex behaviour when tested in the field. The walls store and release heatprimarily over the 24 hour cycle but also to a lesser degree over periods up to 7 days. Night cooling wouldappear to be reducing the indoor air temperature by up to 2 ºC for a 7 to 10 ºC swing in outdoor airtemperature. When the heating is off, the indoor living air room temperature lags the outdoor air temperatureby only 2 hours on average, with wide variations due to natural ventilation. When the heating is on, however,the time lag for a step change response increases to 3.6 hours, suggesting that the thermal mass “buffering”is more effective during the heating season. This may be due to a greater proportion of heat exchangebetween the surfaces and air being radiant in the winter, with the use of the under floor heating and thewood burning stove, than in the summer.Despite the inclusion of significant thermal mass, the occupants experienced some mild overheating in theupper storey of the house during a cool summer in the first year of occupation, with indoor temperaturesoccasionally reaching 25-26ºC due in part to solar gains through the south facing roof. This demonstratesthe need to identify where the major solar gains are likely to arise during the summer then locate the thermalmass as close as possible to the sources of those gains, when designing the house. The house had acomparatively short four month heating season and the residents felt that the house was consistently warmand cosy, with a very even and pleasant temperature throughout the year. This can be attributed to thecombination of high insulation and thermal mass in the house, combined with steady low level underfloorheating.

4.2 Ventilation, Moisture Performance and Air QualityWhile the building was relatively air tight with only 0.54 air changes per hour at ambient atmosphericpressure according to the pressure testing (Taylor et al, 2004), the occupants opened the windows a greatdeal of the time throughout the year. There was also ventilation induced by the use of the wood burningstove in the winter and even when not used the chimney provided a small amount of natural ventilation aswarm air vented through it.Ventilations levels in the house where therefore much higher than the generally accepted optimum level of0.5 air changes per hour, which reduced the potential energy performance of the building in the heatingseason, but did not affect its energy performance in the summer. The air tightness of the building was due tothe external sheathing and breather layer rather the clay brick construction itself. The good air tightnessdemonstrates that the construction system used in this project is very tolerant of semi-skilled workmanship.There is no evidence of condensation having occurred any where in the bathroom and bedroom externalwalls throughout the whole year as described in the detailed report on moisture performance (Taylor,2005b). This is particularly significant as it was a year in which the weather was conducive to causinginterstitial condensation with some very cold and some very wet periods. The high levels of naturalventilation in the house meant that the indoor air humidity and moisture content changed very quickly inresponse to changes in the outdoor air. The smaller and slower exchange of water vapour between theinternal air and the clay walls was masked by these changes making it hard to assess the degree to whichthe clay plaster and bricks were tempering the air humidity in the main living areas. Despite thischangeability, the relative air humidity in the house overall always remained within the optimal range of 40-60% while the external air relative humidity ranged from 25%-95% with a mean of 75% which suggests thatthe unfired clay bricks are having some effect.The ability of the unfired bricks to temper the air humidity was examined in the bathroom where there weresharp increases and decreases in air humidity and moisture content, but with controllable ventilation levels.Contrary to expectations there was little difference in the pattern of changes of moisture content in thebathroom air when the extract fan was not operating, suggesting that the main route for the reduction in thespikes in humidity during showering was by absorption/desorption in the clay brick/plaster wall, mainly in theplaster depth. The extract fan would appear to be unnecessary for reducing moisture levels in this bathroomdue this effect. The residents confirmed that condensation never occurred on the internal shower roomwalling when they were showering, which correlates with the monitoring results. They were also very positiveabout the general air quality and humidity levels stating that the house “never felt too dry or too damp” andmaintained this very even atmospheric quality throughout the year. They attribute this to the use of theunfired clay products for the walling.

4.3 Acoustic PerformanceThe acoustic insulation offered by the clay brick internal partitions was partially compromised during the fieldtest, due to flanking sound traveling through the ceiling and the doors. As such, the test was inconsequential.The residents, however, experienced the partitions as offering a high degree of acoustic insulation despitethe fact that the relative open plan design tended to increase noise levels reverberating around the living


room and upper storey bedroom/study areas. The residents have intimated that they will be buildingadditional clay brick partitions to create more privacy in the house both at ground floor and first floor level.

4.4 Summary of Physical EvaluationThe ability of the unfired bricks to store and release heat would appear to have created a degree of “thermalbuffering” although this was less than expected when the heating was off, and did not prevent some mildoverheating in the summer due in part to the lack of thermal mass in critical areas of solar gain. Theexceptional hygroscopic properties of unfired clay were evident in the shower room and it is surmised thatthe relative air humidity in the house remained optimal throughout the monitoring period partly as a result ofthese properties.The brick construction was not particularly relevant for airtightness, which was provided mainly by theexternal sheathing of the building. The acoustic insulation properties of the brick were unproven in the fieldtest, but the residents felt that the bricks provided good acoustic insulation between rooms. When all theresults are taken together, the use of unfired clay brick and clay plaster has clearly been beneficial in termsof the house performance from the residents point of view, and this has been verified to a degree by themonitoring exercise.

5. Post Occupancy Evaluation

5.1 Complimentary Approach to MonitoringThe Post Occupancy Evaluation (PoE) was particularly helpful in illuminating the results from the physicalmonitoring. The data from the PoE logsheets recorded which days the residents opened windows, whenthere were any unusual events in the house or externally, when they used the woodstove and when theyused the underfloor heating system. The logsheets also recorded the number of showers taken, when thewashing was drying indoors and how many people were in the house on any given day. The level ofinformation obtained was patchy to begin with, but improved towards the end of the monitoring period. Allthis data was carefully corroborated with the graphical outputs from the thermal and moisture monitoring andallowed significant conclusions to be drawn from how the house was actually being used in relation to whatwas monitored. It helped to solve numerous “puzzling” data points, simply by relating them to particular PoEevents that had taken place at these points. In effect, the PoE acted as a form of triangulation for themonitoring data, although there were also instances when the PoE was tantalizingly silent.

5.2 The User EffectAssessing the thermal and moisture performance of the unfired clay products “in the field” illustrates theparticular difficulties involved due to the residents’ behaviour introducing certain effects. The PoE revealedseveral unanticipated user effects which relate directly to the residents’ previous housing history, culturalexperience and preferences.The largest effect came from the residents attitudes towards ventilation and heating. Having previously livedin a very inefficient and draughty solid stone cottage which used a lot of fuel and needed significantventilation to control condensation, the residents were quite happy to continue with this regime in their newhouse, once they realised that their energy bills would still be lower than in their old cottage. They expresseda preference for “fresh air at night” which led to one bedroom window being left open almost permanentlyand others being left open all day. They insisted this was quite normal behaviour in Scotland, and this hassince been verified by another study (Stevenson, 2005b). This user effect has also been observed in airtighthousing designed to use mechanical heat recovery systems (Macintosh, 2005). Future design of energyefficient housing and monitoring will have to take account of the user’s desire for opening windows.Another surprising effect was the excessive use of artificial lighting during the day, despite adequateamounts of daylight being available. The residents admitted that they “left the living room lights on most ofthe day”. This arose from the residents’ preference for “lots of light” as well as their having previously lived ina cottage which needed almost continuous artificial lighting due to its small windows. This effect wassignificant given that there were six halogen lamps in the kitchen radiating heat on a relatively constant basisand effectively acting as continuous mini heater in the house.The final unanticipated effect was the residents’ initial lack of engagement with the central heating controlsystem, based on their lack of experience with underfloor heating. In the first cold season, they simply leftthe heating thermostat set at 21ºC in order to achieve comfort levels with no real thought of optimisation. Inthe second cold season, however, they learned to turn the heating down one degree and use the woodstoveas a more responsive “top up” to optimise the heating regime.All of these user effects have contributed towards the building underperforming in terms of energy use (66.5GJ for the year, compared to the estimated 45 GJ). The identification of these effects may also help toexplain in part why other monitored energy efficient houses in Scotland have failed to achieve their targets. Itpoints up the importance of using PoE to understand building performance and relate future design more


closely to user behaviour. Both PoE and monitoring should form an inherent part of any demonstrationprogramme because designing without feedback is a bit like driving when you’re blind –you really have noidea where you are going.

5.3 TrainingAnother important finding from the research is the need to provide guidance and training for residentsmoving into a different housing type from the one they are used to. A careful explanation of how to optimisethe buildings performance should be complimented by “hands on” experimentation with control settings andventilation strategies as part of the training for living in a slow response, relatively air tight building. It mayeven be necessary to ask the residents to suspend their belief systems and reduce the ventilation theybelieve is required to maintain satisfactory air quality for period of time, to prove to them that this is not thecase. Intriguingly in the case of this project, the residents pointed out that their daughter “slept with thewindow closed” and still enjoyed good air quality, but despite this fact, they persisted in keeping their ownbedroom window open.

6. Conclusions

6.1 The Multiple Benefits of Unfired Clay in Local ConstructionThe research demonstrates that the use of unfired clay in locally sourced and manufactured constructionproducts which are biodegradeable, create little waste, and relatively easily worked with by local builders andsemi-skilled residents alike, is an optimally bioregional approach to sustainable design. This includescommunity empowerment through stimulation of the local economy and the specification of ecologicallyappropriate materials for the area (McGinnis, 1999). It has had multiple other benefits including positivehealth benefits for the builder and user through its benign and hygroscopic properties, providing a degree ofuseful thermal mass, low embodied energy and transport costs as well as providing a strong sense of localidentity and place. The success of this approach challenges construction industries to reduce theenvironmental impact of their production through decentralisation and use of natural, local materials as far aspossible when engaged in rural construction (Berge, 2000). The ability of unfired clay to help maintainoptimal relative humidity levels indoors could also prove very useful in combating increasing incidents ofasthma, which currently affects one in three teenagers in Scotland, and are often related to relatively high orlow humidity levels inside buildings (Puttick, 2004).

6.2 Holistic EvaluationThis project has combined research “in the round” to examine the performance of building products inrelation to both a particular place as well as in the building itself. It has examined almost every aspect of theproducts lifecycle, as it has actually been used, including manufacture, transportation, construction andperformance in use. The only aspect missing is the point of demolition, which is hopefully many years hence.The waste aspect of demolition has, however, also been partially demonstrated through waste arising duringconstruction. It has also examined how the user responds to the product as a part of their environment, aswell as how well the product has been employed through the design of the building. As a result, valuableguidance has emerged on how to optimise the use of unfired clay products in housing.The combined results of this research indicate that it is impossible to separate the performance of the unfiredclay bricks and plaster from the construction process and practice, house design as well as the occupanteffects in attempting to come to an overall appraisal of the products. It demonstrates that this form of holisticevaluation is essential in uncovering numerous hidden factors in the actual field performance of theseconstruction materials. Analysing the performance of products and buildings “in the field” can never replacethe work that takes place in a laboratory –these two activities are essentially complimentary. Laboratoryanalysis offers a degree of scientific certainty that fieldwork can rarely replicate. On the other hand, withoutfield trials which involve the building in use, products are untested in reality.Finally, an important point to emerge from this research is that any scientific assessment of the performanceof a building product has to engage with people’s responses and subjective values in relation to where theylive and the particular cultural background they come from. A great amount of generic analysis has beencarried out on sustainable buildings which attempts to create a “level playing field” for their evaluation. Thisis perhaps a mistake, as each building must be looked at specifically in its context and use, and this makes itunique. Equally, universal benchmarking is a chimera without more particularised benchmarking that relatesto a given locality in all its complexity.


References

Berge, B. 2000, Ecology of building materials, Architectural Press.

British Gypsum,2004, www.british-gypsum.com/immediacy-1276 (accessed on 11/1/05).

CIBSE. 2005, Climate Change and the indoor environment: impacts and adaptation, TM36:2005.

Davies,I, Walker,B.,Pendlebury, J. 2002, Timber Cladding in Scotland, Arca Publications.

DETR. 2000, Building a Better Quality of Life: A Strategy for More Sustainable Construction the UK, TheStationery Office (www.construction.detr.gov.uk).

Macintosh, A., Steemers, K. 2005, Ventilation strategies for urban housing: lessons from a PoE case study,Building Research and Information, 33, pp. 17-31.

McGinnis, M. (ed.) 1999, Bioregionalism, Routledge.

Puttick, H. 2004, http://www.govanlc.com/childasthma_herald (accessed 26.02.05).

RCEP. 2000, Energy –the Changing Climate:Summary of the Royal Commission on EnvironmentalPollution’s Report, (http://www.recep.org.uk/energy.html).

Roaf, S., Fuentes, M. and Thomas,S. 2001, Ecohouse: A Design Guide, Architectural Press.

Polanyi,M. 1966, The Tacit Dimension, Routledge.

Seaden, G. 2003, The role of the client in shaping the satisfactory outcome of the construction process. InCole, R. and Lorch, R. (eds.), Buildings, Culture and Environment: informing local and global practices,Blackwell, pp.130-153.

SEPA. 2003, National Waste Plan. http://www.sepa.org.uk/nws/guidance/nwp_html/index.html (accessed25.02.05).

Stevenson, F. 2005a, Embodied Energy and Carbon Dioxide Calculation for Unfired Earth Bricks at DalguiseHouse, Unpublished report as part of Dti Partnership in Innovation Project O-02-TMA1, Low Cost EarthConstruction.

Stevenson, F. 2005b, Evaluation of Kincardine O Neil innovative rural housing design project: CanmorePlace, Communities Scotland.

Stewart Milne. 2003, http://business.scotsman.com/index.cfm?id=791772003 (accessed 25.02.05).

Taylor, B. 2005a, Thermal Performance of Unfired Clay Brick Construction. Unpublished report as part of DtiPartnership in Innovation Project O-02-TMA1, Low Cost Earth Construction.

Taylor, B. 2005b, Moisture Performance of Unfired Clay Brick Construction. Unpublished report as part of DtiPartnership in Innovation Project O-02-TMA1, Low Cost Earth Construction.

Taylor, B., Soliva, C. and Ross, C. 2004, Measurement of Air Permeability of Unfired Clay BrickConstruction. Unpublished report as part of Dti Partnership in Innovation Project O-02-TMA1, Low CostEarth Construction.

Taylor, B., Stevenson, F., and Morton, T. 2005, Thermal Performance of Unfired Clay Brick House. InProceedings of the World Renewable Energy Congress, The University of Aberdeen (forthcomingpublication).


optimising the use of unfired clay products in rural ... · optimising the use of unfired clay...

Documents