Year Three Technical Investigation Healthy Materials by Vic

VICTORIA MILLER ARC 6012 TECHNICAL INVESTIGATION REPORT SUSTAINABLE SELF BUILD S17138146

What materials could be used to make a self built house healthier and more environmentally responsible?

CONTENTS

Page

Introduction

The Aim and Research Methodologies

Background

Graven Hill Site Visit

Materials Matter

The System

9-10

Why are healthy materials important?

11-12

Analysing the challenging areas in the system

Alternative Solutions

14-19

Insulation

14-16

Plasterboard

17-18

Concrete

Conclusion

References

21-23

List of Figures

Appendix 25-29 Group Project

Introduction Amid the current housing crisis in the UK, RIBA has also declared an environment and climate emergency action plan. The action plan supports a zero carbon built environment, but with many of the current commercial new builds using industry standard materials which have a huge impact on the environment and peoples health this report will investigate how changing the standard materials could make the house a healthier and more environmentally conscious build. An investigation into projects which have used healthier materials will highlight the use of materials which have low impact implications on peoples health and the environment. The healthier material suggestions will be applied to the self build timber frame system designed with Cherwell District Council’s Build! Initiative programme who aim to deliver affordable housing across Oxfordshire.

The Aim

Research Methodologies

1. Investigate what makes a material healthy

1. Visit to Cherwell District Council in North Oxfordshire with an informative presentation about all the projects, programmes and schemes available.

2. Recognise the importance of using healthier, sustainable materials 3. Analyse the timber framed self build system

2. Visit to Graven Hill with a tour explaining how the site works and the various types of housing available.

4. Highlight the areas of the house which could use healthier materials

3. Desktop research : The question is topical in accordance with RIBA climate emergency declaration and the ‘Prescription for Healthier Building Materials: A Design and Implementation Protocol’ which was developed by Arup and published through the AIA which guides teams on more sustainable approaches to building providing more transparency on the materials impact on the environment as well as the human health impacts.

5. Analyse precedents which have successfully used healthier materials 6. Summarise

Background Cherwell District Council are at the forefront of providing self build opportunites to local people with two main programmes available : the Graven Hill development and the Build! Programme. There is an increasing demand for custom builds and self builds in the UK and Cherwell District Council’s Graven Hill enables individuals to design and build a house which is completely unique to the house next door. Situated in open, green spaces surrounded by woodlands and a network of green corridors for walkers and cyclists, Graven Hill is the largest development in the UK which allows self build and custom build opportunities. Once used as Ministry of Defence land, the council bought the hundreds of acres of disused land and have created street layouts with plots ready to build on as well as a school and a pub creating a new village. Self build projects account for approximately 12,000 new houses in England every year and provides individuals the opportunity to choose the materials which ultimately impact the owners, the builders, the environment and the efficiency and sustainability of the house. Graven Hill attracts people with a variety of scales of budget and enables the individuals to have the choice of a pre prepared plot and then have the choice of how to go forward with many designing and building the house themselves, under guidance. The Build! programme is another alternative way Cherwell District Council delivers housing for local people. Set up in 2012, this initiative delvers affordable housing to people on the housing register and so far has provided 260 homes across the District. The Build! Programme enables people on the housing register list opportunities to help build their home and fit their own kitchen all under the guidance of the site managers and in return they would receive a discount on the purchase price. This initiative also works with local apprentices providing job opportunites working on real projects. Figure 1 : Self build made simple with Graven Hill. Source: Facit Homes (2018)

Graven Hill Site Visit The tour showed us the variety of housing and building techniques.

Figure: 2-9 Site Visit to Biscester Source: Authors Own (2019)

Materials Matter According to Klepeis (2001) people spend approximately 90% of their time indoors and research in the last decade has proven that many of the materials that are breathed in expose them to hazardous and toxic materials which provide a poor indoor air quality which can have serious long term health implications. Whilst the manufacturers, architects, designers and builders are aware of the affects these materials can have they are widely used in the built environment and will continue to be used until there is a larger demand for the use of healthier materials because it is a market driven division.

Healthy Material

Unhealthy Material

These are materials which can reduce the toxicity in the home improving the indoor air quality, providing a healthier indoor environment to live in. These materials also have a low impact on the environment during process.

Materials which either absorb or emit VOCs and other pollutants which can affect the indoor air quality

The System The self built house which has been designed for Cherwell District Council’s clients looks at using a timber frame with a passive house equivalent system. This building system provides a quick to construct method and delivers an energy efficient home for the client but the materials chosen could recognise the potential in reducing the energy, environmental and health impacts ensuring a healthier outcome for humans and the environment. The life cycle of the products which are harmful mean people during the extraction, manufacturing, transporting, installing and ultimately the disposal of the product are exposed to the hazardous products as well as also having a detrimental impact of the environment. With the transparancy of such materials and with the availablitly of better alternative materials which are much more environmentally conscious and do not have high toxicity levels during manufacturing, installation and in the home these can provide ‘remedies for sick buildings’ (Woolley, 2017).

OUTSIDE

INSIDE

9 8 7 6

11 12 13

5 5

5 14

2 1

Window to Wall Join Detail Scale1:10 1. 12 mm plasterboard 2. 60 mm insulation 3. Damp proof membrane (DPM) 4. 12 mm OSB 5. 100 mm insulation 6. 150 mm x 50 mm Load bearing timber 7. Insulation to prevent thermal bridging

8. 60 mm cill batten to prevent thermal bridging and secure cill 9. 20 mm cill board 10. Tripple glazing window 11. Window Cill 12. 25 mm cladding battens 13. 100 mm timber frame 14. 12 mm OSB 15. Damp proof membrance (DPM) 16. 15 mm red cedar verticle cladding

Figure 10 Cross section of wall detail Source: Window to wall group (2019) 9

1:10 12

6 14 13 4

5 2

1 16

1:50

16 12

Window to Wall Join Detail Scale 1:10 and 1:50 1. 12 mm plasterboard 2. 60 mm insulation 3. Damp proof membrane (DPM) 4. 12 mm OSB 5. 100 mm insulation 6. 150 mm x 50 mm Load bearing timber 7. Insulation to prevent thermal bridging

5 14

5 5

2 4

Figure 10 Cross section of wall detail Source: Window to wall group (2019)

Why is it important to try and use healthier materials?

VOCs Volatile Organic Compounds (VOCs) are measured using two different types of technologies. The first one uses flame ionisation detection and the second uses photo ionisation detection, both measure the number of chemical particles in the atmosphere.

People are exposed to air pollutants both indoors and outdoors but with new research showing that with people spending much more time indoors, they are being exposed to air pollutants which have significant adverse affects on their health. Building construction and how the home is used needs to assessed. There are construction materials available which do not expose people to such high quantities of pollutants but they do not neccessarily provide the desired budgets, speed or aesthetic.

VOCs are emitted as gases from certain materials and are important to address because there are a variety of chemicals which can have long term health implications. VOCs are up to ten times higher indoors and are found in household cleaning products, wood preservatives, paints and building materials.

“Poor indoor air quality can partly be

Formaldehyde

attributed to emissions of formaldehyde and volatile organic compounds (VOCs) from building materials. These emissions negatively affect people’s comfort, health, and productivity. Formaldehyde, which is regarded as a human carcinogen, is of particular concern in the indoor

Formaldehyde is an odourless gas. If there is formaldehyde detected it needs to be tested in a laboratory using ultraviolet detection which is why it is very hazardous. The World Health Organisation (WHO) guideline provides advice and awareness on the adverse effects of exposure to the common indoor air pollutants and discusses multiple solutions to prevent high concentrated levels indoors.

”

environment. Woolley, 2017

In the book it discusses the indirect sources of formaldehyde which occur through the oxidation How are materials measured? of VOCs and during a survey carried out by Building regularions establishment (BRE) in the UK between 1997-1999 presented between 0.2 According to the Wolrd Health Organisations 1.7 ppm with the standard acceptable level in the ‘WHO Guidelines for Indoor Air Quality’ the UK being 0.75 ppm. approach to setting air quality guidelines is based on reviewing scientific evidence which There are some residential fibreglass insulations links the health outcomes of the exposure to bearing formaldehyde based binders which selected common pollutants found in homes and are dangerous if breathed in. Formaldehyde locates the indoor sources and pathways to said is a carcinogen and during the manufacturing, exposure. installation and disposal stages the correct personal protective equipment (PPE) must be There are many different components which worn. The fibreglass insulation is non- biogradable produce pollutants within the construction of the because fibregalss is a non biodegradable house and so different measuring systems apply. substance but this substance ensures the product This report will focus on the pollutants which are is resistant to mold however the mold is still able hazardous, cause long term health issues but to grow on fibreglass. Woolley, (2017) writes have healthier alternatives which perform well. that Tedhams, the manager for a residential insulation manufacturers claims “It’s pretty clear in the industry that fibreglass insulation is not a contributor to indoor - air quality issues”. 11

“Air pollutant levels are 2 - 5 times higher indoors”

However, in most homes the insulation is reguarly fitted with a vapour permeadble plasterboard so this needs to be recognised as contributing to poor indoor air quality.

epa (2018) Indoor Air Quality. Available at: https://www.epa.gov/reportenvironment/indoor-air-quality

Formaldehyde can also be found in some other products in the house including paints, carpets, composite woods and naturually occurs in raw wood however the wood composites provide a significant source of VOCs as the heat treatments, adhesives, resins and glues are used to combine them.

Practicing Sustainability A sustainable material is one which is non toxic, can be disposed of safely and in many cases can stand the test of time. Some building materials are often not designed to be recycled and can consume a lot of energy to produce and manufacture and then can create more waste once demolished becoming part of a construction waste landfill landscape.

Measuring the harmful chemicals which are released from materials in the home is a very important process to prevent the exposure to the chemicals and to provide the highest air quality standard possible for the home owner. However, another stage in assessing whether the material is considered healthy is to trace the life cycle of the product from extraction to disposal which can determine whether this product is sustainble and environmentally responsible.

In terms of the Brundtland definition, sustainability is about providing for the needs of the present generation without compromising the needs of the future generations (Brundtland 1987).

The BREEAM BRE Environmental and Sustainability 2008 Standard Assessor Manual reads that the use of materials has a direct impact on project costs and the type of materials seclected can have a wide range of impacts on the environment and where possible use

Sustainable building design is dependant on designing efficiently and resourcing responsibly and effectively to ensure all stages of the process have the least impact possible on the environment. As Liddell (2013) points out, some forms of timber become toxic waste from the moment they are treated potentially making a product that will only have one use and cannot be used for anything else as well as causing a problem to dispose of.

- local materials - responsibly sourced materials - materials with a high recycled content - non toxic materials - materials with a low embodied impact - durable materials - materials which minimise need for waste and disposal As well as re-considering using materials which have high toxicity levels.

“420 tonnes of materials were used by the UK construction industry each year

Of these materials approximately 120 tonnes became waste

”

RMF (2019) Construction waste facts. Available at: https://www.rmfservices.co.uk/recycled_raised_flooring/construction_waste_facts.aspx [ Accessed on 12.12.19]

However, the future direction of using healthier materials to create lower impact building designs resembles vernacular dwellings our ancestors would have built. Using natural, renewable materials made from biological sources such as wool and straw which can be combined with low impact materials such as lime and earth mixed into composites provide building materials which cause less pollution and use less energy to grow and produce (Woolley, 2013). Whilst these materials are not innovative, using them in such a way that does not make the house look so ‘handmade’ will ensure the house design is more desirable to more people and so will be used in mainstream construction.

Analysing the challenging areas in the system

Timber

Wall Structure

Plasterboard Paint / Finishes Insulation OSB

Flooring (Carpets)

Floor and Foundation Structure

Concrete

In a standard commercially built house, none of these materials are sustainable and considered healthy materials. Is this material healthy?

Yes, it’s healthy!

Timber Plasterboard Wall finishes (specifically paints) Insulation OSB Concrete Foundations Flooring (specifically carpets) Figure 10 Cross section of wall detail Source: Window to wall group (2019) Figure 11 Concrete Section detail. Source: Foundations / floor to door join group

Nope!

Are there solutions?

Alternative solutions This report will discuss the alternative options for the three materials which have the largest envionmental impact and affect the indoor air quality: insulation, plasterboard and concrete. Insulation The system designed for the Cherwell District Council uses a total of 460 mm of insulation in order for the system to achieve passive house equivalence. By achieving this level of air tightness on the house ensures a cleaner, healthier indoor living environment for the occupiers.

House with a high level of air tightness Reduced energy usage Lower CO2 emissions Lower energy bills Healthier indoor living environment

The wall to window join model that the group created uses Steico Flex wood fibre insulation which is considered a healthy material and can be used throughout the house within the walls, floor and roof.

The Future Homes Standard 2025 is a commitment set out by the government to ensure energy efficient standards are met by the 2050 target. The expectation when following this is that the average home will produce 75-80% less carbon emissions compared to the current energy efficient requirements now. There is a plan for two options: Option 1 looks at ‘future homes fabric’ ideal delivering less heat loss throughout the house or option 2 looks at ‘fabric plus technology’ where the standards are similar to current standards now but will be used alongside low carbon heating and technology.

This product is traceable, the raw wood is sourced from a sustainable forest and is FSC and / or PEFC certified. The alternative insulation options which could be used within this house design are Mineral rock wool or Hempcrete. Hempcrete would change the timber frame system but the provides a load bearing structure whilst providing thermal mass as it acts as insulation too.

Option 1: 20% reduction in carbon emissions compared to the current standard for an average home and this would be partly achieved with using triple glazing, which is what is used in the Cherwell District Council system. Option 2: 31% reduction in carbon emissions compared to the current standard now for an average home now but uses double glazing not triple. Option 2 is the current preferred option delivering reduced carbon emissions resulting in lower bills but the building costs are much higher than option 1. Option 1 is similar to the fabric first approach to sustainable construction and addresses more issues than simply carbon emissions of the household but option 2 is more achieveable with the time given.

House with a low level of air tightness Energy leakage Growing CO2 emissions High energy bills Mould Growth Poor indoor air quality

Standard House Wall Section

Timber framed hybrid with passive house equivalence

Material

Measurement

Material

Measurement

External Brick

112.5 mm

External red cedar verticle cladding

15 mm

Cavity Wall filled with 100 mm Insulation (no air gap)

Timber batten (air gap)(then DPM)

25 mm

Internal Blockwork

100 mm

Insulation

100 mm

Plasterboard

12mm

OSB (then DPM)

12 mm

Insulation

300 mm

OSB (then DPM)

12 mm

Insulation

60 mm

Plasterboard

12 mm

Standard (lowest) 0.3 W / (m2K) u value for this type of system

This wall structure 0.14 W/ (mK) with passive house equivalence achieve a u value

Figure 12 Wall sections. Source: Authors own Photograph model showing the window to wall structure Source: Group

The hybrid timber framed system provides passive house equivalence which is a good long term solution but it is obvious to see the building cost will be significanltly higher.

Mineral Rock Wool

The thickness of the insulation helps the building achieve passive house standard which increases the air quality indoors however an insulation which does not contains zero pollutants or low pollutants to peoples health and the enviornment needs to be introduced.

This system looks at using three layers of rock wool in a stud wall to optimise passive house equivalence.

The table below analyses the use of two of the commonly used healthier insulations, wood fiber and rock wool. The model the group made used wood fibre but either of these insulations are suitable.

Straw Bales This system offers one solution to use a low impact building material which can be locally sourced and performs well as insulation. Straw bales can also be used as the main load bearing structure too. Advantages Low cost renewable material Can be locally sourced Very good insulation qualities

Disadvantages Bales vary in size Concern if there is flood damage Requires external and internal finishes Allergen risk

Avoids thermal bridging and can provide good levels or air tightness

Test

Steico_ Flex Wood Fibre

Mineral Rock Wool

VOC Emission

80 mg/m3

220 mg/m3

Formaldehyde Emission

62 mg/m3

below 9 mg/m3

Carcinogenic Compound Emissions Presence of Flame Retardants

0 mg/m3

YES

Toxic in a Fire

Presence of Pesticides

Wood fibre and mineral rock wool insulation are increasing in popularity for their high standards of producing low emissions.

Figure 13 Straw bale monochrome house in Ontario. Source: Koff N (2015) Figure 14 - 15 Not the last straw. Source: Paczek, T (2017)

Figure 16 Choosing the right wall assembly. Source:Gibson, S (2013)

Plasterboard

The averge radon level in a UK home is 20 bq / m3

Clay Plaster Advantages

Water Resistant

Good at absorbing atmospheric humidity Non toxic Can be locally sourced Hypo-allergenic

Low carbon footprint Made using raw materials which would otherwise be waste, ECOboards can be recycled and given another use.

2 34

Insulation

Gypsum base plaster Gypsum plaster Paint

When analysing the structure of the wall it contains plasterboard and OSB which both emit unhealthy pollutants. ECOboards provide a healthy alternative for chipboard, MDF, OSB and plywood.

ECOboard Advantages

Clay Plaster Wall

Commercial Wall

Radon is a naturally occuring radioactive gas in the ground or bedrock. Radon levels can be expected to be higher in the lower section of a house if built on bedrock but there are many cases where radon levels have been high with the problem being traced back to gypsum plasterboard where the material is contamiated with the radioactive gas. Plasterboard is also often the only barrier between the inner wall insulation and the resident which means they are exposed to VOCs, fibres released by the insulation materials and as some plasterboards are susceptible to mould growth there is the possibility there will be spores in the atmosphere from this.

1 Insulation 2 Base coat of clay plaster 3 Top coat of clay plaster with pigment

Wall Build Up Commercial Wall

Embodied energy per m2 3.2 kg CO2e

Clay plaster wall

0.8 kgCO2e

Performance

Clay Plaster

Plaster

Cement

Conventional Emulsion Paint

Yes

Breathable

Mould Resistant

Dust Free

Easy to maintain

Absorbs toxics

Durable

One plasterboard alternative which provides also delivers the final internal finish is a clay wall applied similarly to wet plaster.

Healthy

excellent

Clay vapour resistance R factor = 30 - 50 MNs / gm

good

poor

Data sourced from clay works (2019) sustainability.Available at https://clay-works.com/specifications/sustainability/

Applied by hand clay can be mixed with straw to make a composite. Together, the materials provide a non toxic indoor environment.

Clay plasters are increasing in popularity in retail and commercial spaces. Snohettas design for Aesop in London recieved a Surface Design Award in 2019.

Clay plaster has one of the lowest embodied CO2 emissions due to local extraction, and low energy required during processing. For optimum comfort to create a healthy indoor environment humidity levels should be maintained between 30 - 70% which clay plasters naturally meet.

Figure 17 Applying red clay made from the site soil. Source: Simply Construct: Straw and Clay (2018) Figure 18 Clay House by Simon Astridge. Source: Worley, N (2016) Figure 19 Aesop Store, Duke of York Square. Source:Aesop Skincare (2019)

“

Concrete

The building sector within the EU consumes roughly 40% of the end use of energy and causes around 1/3 of the EUS

Concrete emits alot of radiation depending on the moisture content. Blast furnace slag = 50% higher radiation emissions that normal concrete

”

carbon emissions

Lime concrete is a natural composite and any waste product will eventually disintegrate into the soil.

Liddell, 2010

Liddell discusses in his 2010 CPD, “the obsession with the carbon atom is at the detrement of all the other issues we need to be dealing with...we need a holistic approach” which looks at how there have been innovative environmental houses built which have technologies attached and fitted throughout the house but over time have failed thus suggesting that much more needs to be considered before installing technology to reduce the households carbon footprint.

“concrete responsible for 8 % of all c02 emissions” Williams, F (2019)

Lime has been used for building for over 10,000 years and uses less energy to produce than cement because it can burn at a lower temperature.

20%

less carbon emissions

Gais Lista Group Architects, The Non-Toxic House Gaia Lista Group Architects Gigtgti House in Norway provides a non toxic indoor environment with the aim that the house with be environmentally sound as well as providing a healthy, habitable environment. Some of the features in this house have influenced the alternative material suggestions for the house for Cherwell District Council. Some of the features include: Lime concrete as the primary construction material, cellulose fibre insulation, sheep wool has been used around the windows acting as a draught excluder, non toxic paints have been used throughout the house.

Lime burns at 900 - 1000 celsius

Cement burns at over 1300 celsius

Figure 20 Affordable Low Allergy Housing. Source: Gaia Lista (2005)

Conclusion

This report has investigated the criteria for a hosue to be considered a sustainable, healthy home and has outlined the importance of recognising the impact material choices have on all stages during the construction of a house. The timber frame system which has been designed specifically for Cherwell District Council, has been analysed and some of they key high impact components of the house have been given healther material suggestions. Not only would these healthier materials provide a better indoor air quality for the occupiers, but by sourcing from biologically renewable and locally sourced places, where possible, the life cycle of the products ensure the impact on the environment and peoples health is significally lowered. Whilst this means using materials which are natural, the processes are very labour intensive and slower to produce so in the current commercial housing market are not cost effective. However, for a self build project this provides the perfect opportunity to design a low impact house using locally sourced materials and delivering a non toxic indoor environment. This report has referenced key building regularions as well as future building regulation aims which looks at developing houses which produce lower carbon emissions by household and during construction. The key stages in achieving a sustainable, healthy home are : 1. Use locally sourced materials, ensuring carbon emissions during transportation are minimal. 2. Use materials which do not require final finishes such as wood, this reduces the overall cost of the project and the need for sourcing non toxic paints and finishes 3. Use non-toxic materials throughout the house. This ensures the life cycle of the products does not expose people to hazardous chemicals during extraction, manufacturing, transporting, installing and disposal of. This also ensures the indoor air quaility is better to live in. 4. Use biological products which can be mixed to make a composite, this ensures the source is renewable and can be disposed of safely. In order to create buildings which are healthier for the people living there and enhance the surrounding environment architects, designers and builders need to recognise some responsibility in delivering the awareness on chemicals which are in buildings and provide clients with viable options in sustainable builds. 20

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Woolley, T (2013) Low Impact Building. Housing using Renewable Materials. 1st Edn. Place of publication: West Sussex. Publisher: John Wiley & Sons, Ltd. Video

Liddell, H (2010) RIBA North East CPD. An introduction to eco - minimalism - the antidote to eco bling. [youtube] Available at: https://www.youtube.com/watch?v=zbYp1H7ZLXM [Accessed 12.12.19] Journals Available Online EPA (2018) Indoor Air Quality, EPA’s Report on the Environment. Available at: https://www.epa.gov/reportenvironment/indoor-air-quality. [Accessed 12.12.19] Hurst, W (2019) Why architects need to wake up to the carbon emergency. Available at: https://www.architectsjournal.co.uk/news/why-architects-need-to-wake-up-to-the-carbon-emergency/10040407.article [Accessed: 12.12.19] Klepeis, N et al (2001) The National Human Activity Pattern Survey (NHAPS): a resource for assessing exposure to environmental pollutants. Journal of Exposure Analysis and Environmental Epidemiology, Volume 11 (Issue 3). Available at: http://dx.doi.org.ezproxy.bcu.ac.uk/10.1038/sj.jea.7500165 RIBA (2019) Five ways house design can help with the climate emergency. Available at : https://www.architecture. com/knowledge-and-resources/knowledge-landing-page/five-ways-house-design-can-help-with-the-climateemergency [Accessed on 12.12.19] RIBA (2019) RIBA declares environment and climate emergency and commits to action plan. Available at: https:// www.architecture.com/knowledge-and-resources/knowledge-landing-page/riba-declares-environment-and-climateemergency-and-commits-to-action-plan [Accessed on 12.12.19] RMF (2019) Construction waste facts. Available at: https://www.rmf-services.co.uk/recycled_raised_flooring/ construction_waste_facts.aspx [ Accessed on 12.12.19] Williams, F (2019) Concrete responsible for 8 per cent of all CO2 emissions, says report. Available at: https://www. architectsjournal.co.uk/news/concrete-responsible-for-8-per-cent-of-all-co2-emissions-says-report/10038404.article [Accessed on 12.12.19]

Online Sites Aesop Skincare (2019) Aesop Store, Duke of York Square. Available at: https://clay-works.com/?gallery=aesop-dukeyork-square-london [Accessed 12.12.19] Cherwell District Councl (2019) About Build!. Avalable at: https://www.cherwell.gov.uk/info/205/build/553/about-build [Accessed on 12.12.19] Clayworks (2019) Natural clay plaster wall finishes. Available at: https://clay-works.com/ [Accessed on 12.12.19] Crosson, N (2015) Build tight and ventilate right: airtightness and joined up thinking for joined up building. Available at: http://www.engineersjournal.ie/2015/07/28/achieving-building-airtightness-training-crest-need-joined-thinking-joinedbuilding/ [Accessed 12.12.19] Facit Homes (2018) Self build made simple with Graven Hill. Available at: http://facit-homes.com/self-build-made-simple-graven-hill [Accessed on: 12.12.19] Friendly Materials (2019) Materials Library. Available at: https://www.friendlymaterials.com/en/insulation/naturalinsulators/fiberboard/flex [Accessed 12.12.19] Gibson, S (2013) Choosing the right wall assembly.Available at: https://www.greenbuildingadvisor.com/article/ choosing-the-right-wall-assembly-2013 [Accessed 12.12.19] Graven Hill (2018) Graven Hill. Imagine. Create. Build. Live. Available at: https://www.gravenhill.co.uk/about-graven-hill/ [Accessed on 12.12.19] Healthy Affordable Materials Project (2016) Healthy Affordable Materials Project. Available at: http:// healthymaterialshealthyhomes.org/ [Accessed on 12.12.19] Kent, D (2007) Lime is a much greener option than cement. Available at: https://www.theguardian.com/ commentisfree/2007/oct/23/comment.comment. [Accessed 12.12.19] Koff N (2015) Straw bale monochrome house in Ontario. Availabel at: https://www.dezeen.com/2015/12/10/k-housenicolas-koff-hamilton-ontario-charred-timber-straw-bales-insulation-monochrome/ [Accessed 12.12.19] Paczek, T (2017) Not the last straw. Available at: https://www.australiandesignreview.com/architecture/not-the-laststraw/ [Accessed 12.12.19] RMF (2019) Construction waste facts. Available at: https://www.rmf-services.co.uk/recycled_raised_flooring/ construction_waste_facts.aspx [ Accessed on 12.12.19] Simply Construct: Straw and Clay (2018) Applying red clay made from the site soil. Available at: https://www.facebook. com/simple.construct/photos/a.372136202805800/1780485741970832/?type=3&theater [Accessed on: 12.12.19] Tyunnos (2016) A house in one night. Available at : http://www.tyunnos.co.uk/ [Accessed on 12.12.19] Worley, N (2016) Clay House by Simon Astridge. Available at: https://www.nicholasworley.com/clay-house/ [ Accessed 12.12.19]

All diagrams authors own or window to wall group unless stated.

List of Figures Figure 1: Facit Homes (2018) Self build made simple with Graven Hill. Available at: http://facit-homes.com/self-build-made-simple-graven-hill [Accessed on: 12.12.19] Figure 2-9: Authors Own (2019) Site Visit to Biscester Figure 10: Cross section of wall detail drawn by window to wall join detail group Figure 11: Concrete Section detail drawn by the foundations/ floor to door join group Figure 12: Authors Own (2019) Photograph of group model showing the window to wall structure Figure 13: Koff N (2015) Straw bale monochrome house in Ontario. Availabel at: https://www.dezeen.com/2015/12/10/ k-house-nicolas-koff-hamilton-ontario-charred-timber-straw-bales-insulation-monochrome/ [Accessed 12.12.19] Figure 14 - 15: Paczek, T (2017) Not the last straw. Available at: https://www.australiandesignreview.com/architecture/ not-the-last-straw/ [Accessed 12.12.19] Figure 16: Gibson, S (2013) Choosing the right wall assembly.Available at: https://www.greenbuildingadvisor.com/ article/choosing-the-right-wall-assembly-2013 [Accessed 12.12.19] Figure 17: Simply Construct: Straw and Clay (2018) Applying red clay made from the site soil. Available at: https:// www.facebook.com/simple.construct/photos/a.372136202805800/1780485741970832/?type=3&theater [Accessed on: 12.12.19] Figure 18: Worley, N (2016) Clay House by Simon Astridge. Available at: https://www.nicholasworley.com/clay-house/ [ Accessed 12.12.19] Figure 19: Aesop Skincare (2019) Aesop Store, Duke of York Square. Available at: https://clay-works. com/?gallery=aesop-duke-york-square-london [Accessed 12.12.19] Figure 20: Gaia Lista (2005) Affordable Low Allergy Housing [photograph] Available at: http://www.gaiagroup.org/ Research/RI/LowAllergyHousing/Final_ALAH_GN_compressed.pdf [Accessed 12.12.19] All diagrams authors own or window to wall group unless stated.

Appendix

Group Project Constructing the window to wall join detail Ritesh Mistry Merdeka French Victoria Miller

Advantages

1. Timber can be pre-cut or cut on site allowing for a faster, easier and high accuracy of construction

5. Environmentally sustainable. The FSC logo assures the wood has come from a forest stewardship council certified forest or is made from post consumer waste

2. The thermal performance of timber is good which means the building will be energy efficient

6. Timber is has a low toxicity 7. Has a great life cycle and in most cases can be re-used and recycled

3. Can be built in varying temperatures, including freezing temperatures

8. Visually appealing so does not need final finished surfaces applied on top

4. Easy to transport and suitable for remote sites

Disadvantages

1. Timber can pose a huge risk for fire but this is preventable with treatments.

4. Most wood is prone to rot and infestataions but is preventable with treatments.

2. Moisture indoors and outdoors from the weather, kitchen, shower etc causes problems but is more manageable and can be prevented using moisture membranes .

5. Whilst timber has a great life cycle, many timber suppliers and treatment facilities are not in the UK and the timber must be transported across the seas to recieved treatment. This increases timbers carbon footprint.

3. Changes in the climate causes timber to shrink, swell and bend.

6. Noise during construction.

Window to Wall Detail Section Development

Model Development

INSIDE

1:10 Side section displaying the build up of the wall and the window to wall

OUTSIDE

1:10 Plan of wall to wall join displaying the hybrid timber frame design

OUTSIDE

INSIDE

Final Model