Confucius Institute Technical Portfolio Anastasia Angeli 1
Introduction This document is a technical substantiation of the main Portfolio that should be seen as one document that complement each other. The document is divided into fours parts, each covering Research, Integration and Reflection.
Contents
Environmental and Sustainability Strategy Structural Strategy Detail Design Design Legislation and Codes References
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Environment and Sustainability
Reflection
Originally I was planning to use CCHP unit on site but then I realized that the energy demand is too little for that and heat recovered from the plant would not be used up and, hence, would be mostly wasted. Hence, a ground source heat pump has been introduced as an alternative heating system. Another thing that I have focused on but did not go in depth was cooling systems as I did not feel that it is required and relied on natural ventilation. In terms of acoustic systems, it has been added after the design has been pretty much settled, hence the acoustic attenuator was an add-on and could require more space than it was given due to its size. Structure-wise, Brettstapel is acknowledged to be an expensive option that may only be viable for prestige construction, although nailed Brettstapel panels have been incorporated into social housing schemes before even in Scotland (Woodknowledge Wales, 2013), hence it was seen as a forward thinking alternative construction system.
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Research Principles of sustainable design Sustainability and environmental comfort have been considered from a variety of levels. I have focused on light, air quality, thermal and acoustic comfort in this section. These elements have been researched, looking into BREEAM and WELL Building standards as well as World Green Building Council guidance (2019). Key key research outcome was that all three areas are interlinked with health, environmental and economic aspects and, hence, need to be considered in a coherent way.
Acoustic challenges
Environmental challenges addressed
In order to achieve a low energy building with natural cross-ventillation, noise break-in from other rooms and outdoor spaces has to be addressed. MACH Honeycomb acoustic attenuator is designed to overcome this issue.
Rain and wind – roof to provide weather resistance
Walls and floors serving interior sound insulation function Noise from external sources – walls to provide weather, thermal and noise insulation
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Heat – insulation and air exchange to be considered
Fire – fire resistance in case of emergency
Dampness – walls and floor to provide adequate damp resistance
Solar radiation – windows to allow light in and shading to prevent overheating
Brettstapel
Summary table of key features of Brettstapel
Brettstapel construction is a massive timber copnstruction (explained in depth in Structure section) that is particularly favoured by architects and clients with environmental aspirations as it can be used to create low embodied energy solid panels capable of replacing masonry or concrete (Woodknowledge Wales, 2013).
Thermal mass
• The only 100% wood mass timber construction product • No metal fixings and no glue • Acts as an insulator and humidity regulator
Performance
• Structural design covered by IBC and NBCC • Proven fire resistance • Long life span
Many houses built to Passivhaus standard have been made with Brettstapel – e.g. House at Batchuns, Austria or Pfennlgäcker Nursery school, Germany Is best suited for low-value timber, of which UK has a great deal.The resultant Brettstapel panels are strong and useful. The major advantage in ecological terms is adding value to low-value timber, which otherwise would be used for paper or pallets (2013).
Flexibility
• Variety of surface profiles available, including acoustic profile for noise reduction • Dimensionally accurate panels due to CNC machining
On site efficiency
• Speed of construction - 2000m² floor plate erected in one week due to prefabrication • Simplified transport and storage due to flat packing of panels
Sustainability
• • • • •
With solid wood with density around 750kg/m – it is thermally massive and reasonably insulative. Open finish in the interior allows panels to absorb moisture from the internal climate, regulating the indoor relative humidity and creating a healthy micro-climate for visitors (Halliday, 2015).
No site waste due to optimised off-site prefabrication Wood fibre sourced locally Average of 1600 kg CO2 captured per one ton Using wood, which is a renewable material Local softwood can be specified as a variety of species can be used, including SPF, Douglas Fir, Hemlock and Cedar • Less volume of product used due to structural efficiency • No toxic additives used and no glue • Possibility of using low-value timber due construction method adding the structural qualities and coherence (Info from Woodknowledge Wales, 2013)
Sustainable artificial lighting strategies The RIBA CPD Roadshow (2019) talk has been attended on Designing with Light presented by John Cullen Lighting company that provided information on latest energy efficient light sources products, building regulations updates, circuiting, control and integration for maximum impact from artificial lighting. It has been suggested that 2700 Kelvins is the best colour temperature for the interior, while the exterior lighting can vary, depending on the location. Colour Rendering Index has been another feature discusses as being influential for the outcome - the higher the better (100 CRI being the best), that allows colours to be represented more accurately - important in the restaurant setting where the appetite could be influenced by this characteristic. Binning is the last characteristic discussed, which is responsible for the uniformity of light (John Cullen Lighting, 2019), resulting in a more consistence colour throughout as the lighting is tightened with more rigour.
Light Characteristics Colour Rendering Index
CRI 70
CRI 80
CRI 90
Colour temperature (Kelvin)
CRI 97
1900 candle flame
2700 warm white light
3000 sunrise/ sunset
5000 noon sunlight
(Colour samples taken from John Cullen, 2019)
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Research Accoya
Relative annual Carbon emissions (kg CO2/year)
Performance benefits of Accoya
Accoya which is manufactured using sustainably sourced wood and achieves aesthetically pleasing, durable, stable, long-lasting results (Williams Homes LTD, 2016).
The study carried out by Camco (Verco) shows Carbon emissions of different structural materials in a bridge structure, comparing Accoya with other typical structural alternatives. The graph shows that Accoya has much lower Carbon foot print per year, comparing to steel , however sustainably sourced Ekki, being carbon capturing, has scored higher in that sense (Accsus Technologies, 2012).
1. Naturally insulating • massive wood resulting in good thermal mass • ideal for energy conservation friendly projects
Due to the ability of achieving greater spans, less stainless steel joints are required, which helps minimise steer material and work required (Accsus Technologies, 2012).
2. Consistent and local supply • produced from average quality softwood • could be manufactured with local woods 3. Non-toxic and recyclable • treatment of the material is non-toxic • can be safely reused and recycled
Accoya
Ekki Ekki Concrete (sustainably (unsustainably sourced) sourced)
Steel
Stages of Accoya production
1. Cutting the trees in the forest - old and weak pieces work just as good due to special treatment that gives its strength
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(Info from Accsus Technologies, 2012)
2. Using chemical principles to change properties of the wood and make it more dureable and structurally strong
3. Treating cut timber planks using Acetic Anhydride and distributed to Arnold Laver in Filton
Copper
Key features
Copper production
Copper is a pure, natural material used for centuries as an effective roof covering, with the added attraction of unique, changing visual characteristics. Its durability and resistance to corrosion offers almost indefinite design life, requiring no (or very little) decoration, maintenance or cleaning. In addition to than copper is environmentally friendly, fully recyclable, safe to use and can be worked at all temperatures (Copper Concept, 2006).
• • • • • • • • •
Mining
Copper is a natural element within the Earth’s crust which has been incorporated into living organisms throughout the evolutionary process (Copper Concept, 2006). Nature is well adapted to making best use of copper, protecting itself from any negative effects. This balance carries through to the long-term effects of man’s use of copper on buildings.
Comparison with other metals
Lightweight Low Thermal Movement No maintenance required Durable Cost Effective Recyclable Low embodied energy Thermal expansion: 0.0168mm/m/˚C (20-100˚) Tensile strength: 210 - 240 N/mm2 (half hard)
Copper
Stainless steel
Aluminium
Thickness (mm)
0.6
0.4
0.7
CO2 equivalent emissions (kg/m²)
6.6
10.9
7.5
Life span (years)
200
100
100
Embodied (MJ/m²)
103.3
157.2
115.4
Energy
Smelting
Fire / electrolytic refining
Scrap cleaned
Melting / alloying
Semi- /continuous casting
Life Cycle of Copper
Metal Corrosion and wear
Metal Extraction
Complex Compound Ion
Mineral
The comparison table shows key benefits of using copper as a cladding and roofing material, mainly due to its long life span, which is twice as long as stainless steel and aluminium. However, for the structural elements copper would not be the best option due to its lack of strength (Copper Life Style, 2012). Copper cladding can also be valued for its changing colour characteristics, the rough guideline of the colour change is shown below (2012). However, it has been noticed recently that in larger cities copper tends to turn more black rather than green due to hight levels of pollution.
Hot rolling
Extrusion
Cold rolling
Drawing
Sheet / strip
Wire / tube
Mineralisation
(Info from Copper Concept, 2006)
(Copper Concept, 2006)
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Integration Sustainability measures from production, implementation to demolition The amount of CO2 emissions that construction can influence is significant, accounting for almost 47% of total CO2 emissions of the UK (Department for Business innovation and skill, 2010), hence it was important to make sure that the key material used in the construction is low in Carbon values and Brettstapel wall on average would capture 1600 kg CO2 per one ton (Structure Craft, 2017). This structure itself is not carbon intensive due to reduced need for timber treatment and use of not very high quality timber (Henderson, 2010). Another way of minimizing Carbon produced by the scheme was to use locally sourced materials with low embodied energy and low Carbon content (Pearce, 2006) and allowing for the material to be reused after the building has been de-constructed.
PV Solar panels at 10 ° facing South
Solar shading strategy, responding to direction it is facing to reduce need for mechanical cooling and heating Plant room with ground source heat pump, connected to the river edge, providing energy
Edible landscape features, enhancing biodiversity, watered with recycled grey water
Brettstapel construction, using untreated local softwood, minimizing energy use at the construction, could be recycled after demolition
Use of crushed bricks from the demolished shed as compact hardcore in the foundation
Greenery and trees enhancing air quality and adding to the future resilience Using reclaimed Accoya timber where structural performance is not a priority, e.g. decking Retrofitting existing buildings to minimise the need of new built where possible 10
Bicycle parking,encouraging active transport modes
Copper
Accoya
Copper has been chosen as a cladding material for buildings, due to the reasons discussed in the Research section. Other materials to be included in the cladding are stainless steel (fixings and structural support of the balconies) and glass. Where possible, reclaimed cladding materials are going to be used in order to reduce energy use of the building at the construction stage.
The key material that is proposed to be used throughout the construction is timber due to its low environmental impact and its versatility. Main cladding and rooftop decking material is Accoya which is not sourced locally, however, is supplied through local businesses as reclaimed material. Having hardwood properties, this softwood seemed to be a perfect material for its extensive use in the scheme.
As discussed in the previous section, copper ages with time, which has been embraced in the project by using not patinated copper to allow it to change through time. Predicted change in of copper colour in 10 years time scale is shown in the images below.
A sample of Accoya has been requested from Arnold Laver in order to check its water resistance (durability was trusted to be high based on research). Images on the right show change of Accoya after it was put in the water for 2 weeks.
Copper straight after completion
New Accoya as it was received
Left in the water for another one week, at a lower level
Copper in 10 years time, expectation
Accoya straight after being left in the water for one week
Taken out of the water for one day after the experiment
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Integration Linking measures with the impact
Environmental considerations
Biophilia has been considered in the main portfolio and the idea of connection with nature has been taken further at the more technical level. Impact of air quality, thermal and acoustic comfort and light have been looked at in relation to health, environmental and economic impact, which is synthesised in a table on the right.
• Greenery is visible from the inside – well-being • Non-toxic paints and furnishings incorporated
• Acoustic Attenuator and thick insulation throughout – comfortable acoustics in study and work spaces • Good airflow
• Access to natural light – connection with nature • Seeing change of light outside – feeling of being alive, being part of the living world
Trees fit into paved areas
• PV panels – green energy – cleaner air for future generations • Outdoor vegetation for Carbon Capture
• Thick insulation and use of Brettstapel – air tightness and less need for heating and cooling • Efficient heating systems – less energy required
• Efficient light bulbs at required intensity and colour temperature • Timers and dimming sensors – using as little energy as possible
Greenery and landscaping is an important feature of the development.The way of incorporating new trees in the paved area has been found with GreenBlue Urban Systems, providing urban landscape solutions throughout the UK.
• Increased clean and fresh air flow • Less need for mechanical ventilation – using hybrid strategy
• PV panels – reduced energy use • Deciduous trees and efficient shape – prevents overheating
• Skylights and white wall finishes –capturing Northern light • Allowing natural light in – increasing human productivity
Evaporating and cooling
From paved area into the Arboflow collector
Internal spaces considerations
Circadian rhythm of artificial light Daylight
Acoustics
Biophilia Movement
Standing up desks
Air quality
Drainage
Ground water recharge 12
Thermal Comfort
Collaboration space
Water strategy and services
Water collection points from the roof into the WCs
Services positioning and water run-off
Rainwater is to be collected by the surface of the roof and collected in water tanks underneath the toilets, under the paving to safe space in the habitable area. This water would then be reused in the toilets and for watering the community garden and other on site greenery (as is shown on the diagram below). The unused water will be discharged back into the river, through the gravel that would slow the surface water runoff, which could become an issue in urban areas with little permeable surfacing. Another consideration that would make a difference for maintenance after the implementation of the scheme, is locating the services in grouped strips in order to minimize maintenance disruption, as shown on the diagram at the right.
Water collection
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Integration Energy strategies
Heating strategy diagram
Due to a relatively small energy demand of the Confucius Institute, no need in a CCHP unit has been identified, hence energy will be captured from the river bank that would then be raised to an appropriate temperature for the underfloor heating (around 38°) by the heat pump and then raised further , when required by an additional system until 65° that could be used in radiators, positioned under extensive window areas, as shown on the diagrams on the right. PV solar panels, added on the roof of the North building (visually hidden with the pitched roof section, facing towards the Redcliffe Parade) at the flat area, angled at 10° to allow for maximum solar capture with access from the stairs for easy maintenance and cleaning when needed.
Solar panels positioning
Light hitting the solar panels at different times of the year
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Heat from water into the building
Solar light and shading
Sun heating the facade
Sun path has been considered in order to make sure that the building benefits from soft North-facing natural light and have the most of the sun light that would have an opportunity to come into the open spaces provided by the scheme.
Another function of the ribbon was pdoviding shading that would still allow light in but at a lower intensity, as can be shown on a diagram below.
Different shadowing strategies have been used on the site to make sure that the Southern facade is shaded at all times with deep fixed shading (combination of vertical on the outside for keep the visual coherence and horizontal elements inside to provide constant shadow) and East and West shading responds to the time of the day with moveable vertical shading and with deciduous trees that would provide shading in the summer and let much wanted low sun light in the winter.
Model of the ribbon at different angles creating different visual transparency through
Depth and width that would achieve best results have been examined throguh modelling, seen on the right having thin and deep strips of timber not only allows selected views in only at certain angles but also woud allow reflected light in ather than direct blinding light.
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4A Rule of thumb for natural lighting allowance distances 15
Integration Solar gain and shading
East / West
South
Measures considered to prevent over heating and minimise need of energy consumption: lower block on the south side allows more light into the north block and the courtyard North-facing rooftop lights and double height spaces make sure the building takes advantage on the natural light cladding is reflective in its nature that helps capturing matural light in otherwise shaded areas, such as a South side of the courtyard ribbon is acting as additional shading to vertical shading added where needed PV panels on the rooftop of the north building installed at 10° angle to capture solar energy
Solar gain and shading Measures considered to prevent over heating and minimise need of energy consumption: • lower block on the south side allows more light into the north block and the courtyard • North-facing rooftop lights and double height spaces make sure the building takes advantage on the natural light • cladding is reflective in its nature that helps capturing matural light in otherwise shaded areas, such as a South side of the courtyard • ribbon is acting as additional shading to vertical shading added where needed • PV panels on the rooftop of the north building installed at 10° angle to capture solar energy
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Letting light at 30°
Ventilation and acoustics Massive timber construction and thick layer of Perlite and cellulose insulation makes sure that the building is air-tight which helps decreasing temperature variation throughout the day. Other Passivhaus concepts have been considered at the design stage of the building. Distance between windows and maximum room widths have been considered in order to allow for sufficient natural ventilation, supported by mechanical ventilation that would be used in the event of hot weather. To stop noise from the outside coming into the building and to provide noise break between areas of different activity Acoustic Attenuator of Mach System has been chosen that can be seen below.
Honeycomb Acoustic Attenuator (Mach system)
Airflow rule of thumb applied
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5A Ventilation strategy
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Structural Strategy
Reflection
At the initial stage, I was looking at folded plate structures and roofs as I felt like it could provide a nice link to paper folding use of the building. However, I soon realized that this structure often requires concrete to be achieved and visually does not create light and translucent paper effect but rather a heavy impactful structure which was not something I was after. This is one of the reasons why I have moved to Brettstapel after looking at its qualities and features. One of the key issues that I came across when designing with Brettstapel was the fact that the literature on Brettstapel is limited due to its small establishment in the UK. Hence, it is often compared with CLT and Glulam. Sustainable benefit is similar, however structural performance comparisons are less understood for Brettstapel. There is little structural data on its performance (Gordon, 2015).
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Research Brettstapel
Span Table
Timber options
Brettstapel (meaning stacked planks), is a solid wood panel type that pioneered in Germany which uses either nails or wooden dowels to fix parallel softwood lamellae together to form structural panels. A resulting panel is anisotropic (vary in different locations) and behaves in a similar manner in expansion as would a large panel cut from solid timber. However, because of the parallel alignment of lamellae, Brettstapel panels may perform better structurally than CLT structurally both as diaphragms and shear walls; under compression Brettstapel can take up to twice the loading of similar sized CLT panels (Smiths, 2013). Brettstapel floor panels are capable of spanning greater distances than other solid wood panels of similar thickness and are therefore also particularly suitable for cantilevered structures. Brettstapel walls have up to twice the load bearing capacity of other solid wood shear walls (Smith, 2013). Brettstapel may be produced in a range of grades, e.g. using low value falling boards for ‘industrial’ grades or high value softwoods such as Douglas fir for exposed ‘architectural grade’ panels.
Typical dimensions
SPF
Douglas Fir
(Woodknowledge, 2013)
Alaskan Yellow Ceddar
Brettstapel composition options
Board 80-300 wide 20-40 thick up to 8000 long
Western Red Cerad
Dowel 18-30 wide/thick 400-600 long Panel 400-600 wide 80-300 thick up to 8000 long 20
(Info from Gordon, 2015)
Hem-Fir
(Structure Craft, 2017)
Accoya Accoya is a new type of wood. It is a so-called acetylated coniferous wood type, which has the same properties as tropical hardwood.Treating it with acetic anhydride creates a sustainable wood that is almost impermeable to water and that is UV resistant. The enormous wooden structures remain light in terms of weight as well as appeal through this use of Accoya. (Accu Grafisch Ontwerpers, 2013) Accoya wood has also proven to be an effective barrier to wood destroying insect damage in multiple field tests and laboratory trials undertaken in many locations in the world. This includes tests with multiple species of termites. A dimensionally stable material that will stay flat and has very minimal bow, cup, warp and split and will not be affected by fungi or rot is desirable. It is also important that the wood is non-toxic and therefore safe for people and animals. Accoya wood meets these requirements. Accoya wood has superior resistance to UV degradation, with extensive tests demonstrating that the natural beauty of the wood lasts longer in even the severest exposed conditions. UV resistance of wood improves the life of any coating by providing a sound coating substrate. It also allows a wider range of feasible colour options. For example, very light pastel coloured stains and clear coatings can be safely used because Accoya will not darken quickly and ruin the effect as most other woods do (Latham, 2019).
Properties of solid ‘Accoya Structural’
Characteristic values (N/mm2 or kg/m3)
Bending Strength
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Tensile strength: Parallel to grain Perpendicular to grain
14 0.4
Compressive strength: Parallel to grain Perpendicular to grain
21 2.5
Shear strength
4
Modulus of elasticity: Parallel to grain Perpendicular to grain
11000 370
Shear modulus
690
Density
380-460
Testing structure for the ribbon element through modelling
(Info from Accsus Technologies, 2012)
Key features: 1. Consistent quality measurable modification quality from surface to core no need to apply chemical preservatives when cut 2. Retained strength and hardness hardness increases with time high strength to weight ratio 3. Excellent machinability easy to process manually no challenges for manufacturers and end users
(Info from Accsus Technologies, 2012)
Accoya structure tested during the Speicify Roadshow at the MoreArt stand
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Case studies Brettstapel Coed y Brenin visitor centre by Architype The building is the first Brettstapel constructed building in the UK to be made from domestically grown and manufactured softwood, which was allowed by the construction system as it makes it possible to create structural walls with not very high quality softwood by putting them together and connecting with hardwood dowels. The scheme has been designed to BREEAM Excellent standard (Woodknowledge Wales, 2013). In Wales, Brettstapel is more often being called ‘Dowellam’ as a more descriptive way of referring to the construction process. An example of a Dowellam building in Wales is the 2013 extension to the Coed y Brenin Visitor Centre near Dolgellau, designed for the Forestry Commission Wales. This was the first ever UK Brettstapel structure to use locally sourced Douglas fir and spruce. Larsen trusses, a type of lightweight vertical two stud framing element, were used to create the exterior insulated envelope, which was filled with cellulose fibre insulation (2013).
(Natural Resources Wales, 2019)
Acharacle School by Gaia Architects The school is one of the first examples in the UK of Brettstapel construction – a glue-free variant of massive timber construction imported from Austria. This has helped to create a highly insulated and airtight school, which easily achieves the internationally recognised German ‘Passivhaus’ standard in terms of fabric performance. (Sust. Architecture + Design Scotland, 2011). All the timber in the building is untreated. The timber used for the Brettstapel panels is Silver fir. As with all timber, this has the ability to absorb a small amount of excessive indoor humidity, which helps to create a healthy indoor environment. (2011)
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(Sust. Architecture + Design Scotland, 2011)
Accoya Ector Hoogstad Architecten’s Reef bench With simple means, Remy&Veenhuizen created a defined area with special significance. The newly built school, which the firm of architects that designed it, Ector Hoogstad Architecten, call ‘a citadel that serves to shield against the ugliness of the surrounding building estate’, has a confined atmosphere. An autonomous village was shaped around a street of light. Remy&Veenhuizen chose to break through this confinement: “We wanted to give the students their own ‘escape area”. This outdoor clubhouse is shaped like stylized dunes, dotted with classic seating elements. Its transparent slatted structure arose by experimenting with spatial models. “This way we keep our freedom of form”, Veenhuizen explains. Designers discovered a method that allowed the slats to move slowly while the construction as a whole still remains solid. Thus, the wooden skeletons look like organic, almost living elements, offering a warm contrast to the school building (Accu Grafisch Ontwerpers, 2013).
(Accu Grafisch Ontwerpers, 2013)
Accoya Burri Moveart’s Playing bench This outdoor furniture company is producing a number of products in Accoya, ranging from outdoor furniture to play spaces. Through a combination of functionality, safety and art, the objects from Moveart offer sustainable solutions for public spaces and of people of all ages. The simple bench offers seating for two people or a space for one person on which to lounge. To support the head and elevate the feet, the upper and lower ends are gently tilted upwards. At the same time, the playful design of the bench lends its own character but does not disrupt existing landscapes (MoveArt, 2019). This achieved through using Accoya that ensures long life of their products and durability.
(MoveArt, 2019)
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Integration Brettstapel
Primary and secondary structural elements
The structure chosen for the building is Brettstapel, also known as Dowellam in English-speaking countries that is a massive timber construction that consists of soft wood planks of timber put together with hardwood dowels. This structure is not carbon intensive due to reduced need for timber treatment and use of not very high quality timber (Henderson, 2010). Structural model on the right is showing the primary and secondary structure - Brettstapel walls.A diagram is showing how the load is transferred, dealing with gravity, bending forces and shear.
Section through Brettstapel panel Bending and gravity being tacked by the massive timber Brettstapel construction
OSB board Staggered internal finish
Hardwood dowels
Compact insulation panels 24
Photographs of the 1:10 model
Structural principles
Construction sequence diagram
Due to the nature of the structural system used in the building, there is no structural grid as massive timber walls take gravitational forces down as well as dealing with shear forces.
The building is composed with a number of different elements, key ones being the Brettstapel structure and Accoya ribbon going over the top. The diagram below shows the structural elements of the building in a sequence of how they would be constructed, using the Brettstapel panels, pre-manufactured off-site in order to achieve higher control of the environment and to minimize time spent on construction on site.
The Brettstapel technology allows structural grade timber components to be created from timber predominantly produced in the UK. The technology involves using short lengths of softwood held together with hardwood dowels which swell and tighten the resulting panel into a massive timber, load bearing wall or floor (Smiths, 2013).
1:10 detail model photographs The model has been created to understand the structure of the building, focusing on a chosen cube 5 Ă— 5 Ă— 5 meters, showing a section through the door, main structure and a ribbon.
1. Concrete foundation cast in-situ
2. Services and lift cores built up
3. Ground floor and structural Brettstapel walls put up with panels, manufactured off-site
4. Brettstapel floor slab put on top
5. First floor built up
6. Second floor erected on the North building with slanted roof
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Integration Brettstapel and gravitation forces Hardwood dowels holding timber planks together allow the structure to deal with shear force and gravity making Brettstapel a unique massive wood construction that does not require glue, which links pack to the paper folding as that form of art does not allow use of glue.
Hard wood dowels connecting Douglas Fir planks
Gravitational forces tackled by Brettstapel
Internally exposed Brettstapel with staggered effect
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1:10 model with gravitational forces shown on top
Accoya Dowel connection used in Brettstapel (Dowellam) has inspired other elements of the design - ribbon folding around the building follows similar strategy by being connected with stainless steel rods.This system is also used in the furniture, both in the interior and outdoors.
Outdoor spaces
Structure (Brettstapel)
Ribbon is connected at the direction change and every 1000 mm with stainless steel aluminium threads, mimicking hardwood dowel connection in Brettstapel.
Dowelled finger connection
Visually uniting element
Functions of a ribbon
Partial internal finish RIBBON
Outdoor flooring
Bicycle parking Diagram of where the ribbon comes down into the building
Benches
Shading
Structural wall taking the load of the ribbon coming down from the roof
Aluminium balcony structure supporting the vertical ribbon
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Detail design
Reflection
Detailing is a part of the project that makes it come together and should be the most exciting part of an architectural project as it is the final stage which makes a project come into life. However, I am personally struggling with it a lot, hence this stage of the project always takes me a lot of effort and trials to achieve something that would work. Saying that, at the end I always find it satisfying seeing the detail that could actually be understood and could potentially make my project be built by other people who could read the detailed drawings and understand how I wanted it to come together to make it do what I wanted it to do.
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Research Brettstapel
Wall composition
This construction method in not popular in the UK yet, hence researching on the details of that system has been crucial in order to make sure that the project could be implemented in the way expected. However, it was Brettstapel that allowed the building to be what it is due to its clean finishes, exposed interior wall finish and variation in composition.
1. 130 mm Brettstapel structural wall 2. 15 mm Plywood 3. 180 mm wood fibre insulation 4. 40 mm Battens and cavity 5. 40 mm vertical timber cladding 6. 40 Ă— 200 mm Hardwood timber boards 7. 100 mm steel cleats 8. 400 Ă— 200 mm steel
Hardwood dowels expanding Dried down hardwood dowels are used with lamellae of considerably higher moisture content so that dowels absorb moisture from lamellae thus expanding and locking them together.
frame
Brettstapel construction sequence
Brettstapel wall sketch 1. Optimising Saw - visual defects cut out (to be reused for paper)
2. Finger-jointer - boards structurally finger-joined into continuous lamella
3. Profile Moulder - lamelas run through the moulder to ensure exact thickness
4. Brettstapel Press - high pressure applied vertically and horizontally, hardwood dowels hydraulically fit sideways into holes
5. Panel Planer - ensuring exact thickness and width and smooth finish
6. Gantry-style CNC Machine - openings, notches and drillings milled into the panels, based on project specification
Hardwood dowels Softwood planks 30
Dealing with gravity and shear forces in detail A number of sources have been consulted in order to understand the detailing strategies for Brettstapel walls. A synthesis of some of the key elements is shown on this page, mostly taken from information available on the Welsh variation of Brettstapel, Dowellam (Woodknowledge Wales, 2013), which is the same structure but called differently in order to relate easier to English-speaking audience.
Infill strip of sheathing nailed on site Timber screws to create shear connection to beams
Longitudal cantilevers up to 3 meters are easily achievable Inclined screw connection Plywood or OSB sheathing Closed cell foam sandwich between boards for airtightness Foam gasket or alternative Brettstapel roof panel
Inclined screw connection to transfer shear load from sheathing diaphragm to beam Brettstapel panel
Infill strip to stitch panels Typical 50-100 mm gap between panels Brettstapel panel edge
Brettstapel panel
Infill strip nailed on site - typical strip is 200 mm
Acoustic mat Screws from below Steel angle
Infill strip of sheathing nailed on site Post fixed screws from below Steel beam
Transverse cantilever screw reinforcement to allow up to 4 meters cantilever Closed cell from gasket sandwich between boards for airtightness
Steel angle to transfer diaphragm and gravity forces Ledger board Gypsum
Brettstapel wall panel Inclined screw connections to transfer shear loads
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Research Curtain wall - Schueco A variety of curtain walling have been considered and Schueco FW 50+ SG curtain wall has been considered to be most fit for the project for its purpose and for the sustainability features it offers.
Profile alternatives in section
Different frame profiles
Tripple glazing
Energy • Stainless steel spacers create an air-tight edge seal • Highly thermally insulated SI isolators minimise thermal breaks Security and automation • Tested as safety suitable with RC 2 burglar resistance • Top-hung or parallel opening window Enhanced function • Structural glazing facade with max dimensions of 2600 mm by 4200 mm • Cost efficient plastic pocket profile
Stainless steel spacers (Schueco, 2019)
Drainage - Aco Aco drainage solution has been chosen after seeing their products at the Specify Roadshow in Bristol where a specialist has described qualities and features of drains and enhanced durability strategies, achieved through having a drain as one block rather than separate elements that could potentially move in relation to each other.
Parquet - Brimstone Wood Specify Roadshow in Bristol had a stand with their products as well where different timber parquet has been shown, all made from treated local timber. A key selling point of the company is the use of not commonly used timber that grows quickly (around 35 for a tree comparing to the average of 100 years for oak tree). This is seen as an important feature as such timber would work perfectly fine for interior parquet, even though the company claims its durability when exposed to weather as well. 32
Photos from the Specify Roadshow event
Insulated SI isolators
Case Studies Brettstapel and steel construction Soft House in Hamburg by Kennedy & Violich
Timber decking The Docks in Saint-Ouen by Attelier du Pont
A wide variety of Brettstapel construction buildings have been looked at in order to understand its principles and limitations. Most of the examples are located in Austria and Germany with some being built in Wales, often related to as Dowellam.
In order to make sure that rooftop terrace covered with Accoya planks is possible, case studies have been carried out. The following case study also is a good example of incorporating greenery into the scheme.
Types of Insulation Today, importance of sustainable development increases the importance of studies on energy efficiency. Residential and industrial fields consume 70% of total energy consumption and constitute the largest portion of it. There is an energy saving potential of 30% in industry and 70% in homes by insulation.The production of low thermal conductivity lightweight insulation materials from domestic resources and diversification of these materials has gained importance (Demir et. al., 2018).
Cellulose Insulation Cellulose fibre insulation is an environmentally-friendly insulation option (Resources Wales, 2019), created with recycled paper - this material links back to the main use of the project, closing the cycle of paper from the paper folding being reused in the insulation at a greater scale. Newsprint
Recycled cellulose
Insulation panels
Cellulose insulation is made of 80% post-consumer recycled newsprint. The fiber is chemically treated with non-toxic compounds that allows it to resist fire, insects and mold. The Cellulose Insulation Manufacturers Association (CIMA) claims that insulating a 140m² house with cellulose will recycle as much newspaper as an individual will consume in 40 years - this number would be less in the Confucius Institute as a lot of paper is going to be used there daily.
Perlite Insulation Expanded perlite aggregates which have different particle size were used as a main raw material. Perlite is a lightweight material due to their high open and closed micro pores. Expanded perlite aggregate has porous structure and hygroscopic properties. In order to prevent these properties, hydrophobic polymer, and organic or mineral acids additives are used to coat the surface (Demir et. al., 2018). Perlite rock
Crushed rock
Expanded
After perlite aggregates get mixed with certain amount of sodium silicate solution (water glass) and shaped in the mold. As a result, coated expanded Perlite insulation has thermal conductivity of a constant lower than 0.060 W/mK (2018). 33
Integration Material choice Timber and copper are two key cladding materials, supported visually with glass in the curtain glazing and doors and Accoya timber, wrapping the building with a series to thin planks. 5
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Key materials 1. Deep and thin Accoya (light in colour timber) ribbon creating a stripped effect, giving a variety of levels of transparency, depending on the angle in which it is looked at 2. Pavement stone with greenery introduced in thin strips, following the visual aesthetics 3. Copper cladding, segmented into 1000 Ă—500 mm sheets creating a subtle horizontal emphasis, contrasting with verticality of the Accoya ribbon
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4. Internally exposed Brettstapel (Douglas Fir softwood) with staggered effect on walls which take the load off the external ribbon that comes down from the roof visually links external Accoya feature with the interior 5. Cellulose insulation in the walls, substituted with Perlite Insulation where weather resistance and structural firmity in needed
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6. Double glazing as a part of ADS 70 HI 2 Schnitte Door (SchĂźco) with concealed stainless steel hinges
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Annotated 1:10 model
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Wall build up
Brettstapel detail 1:5
Brettstapel has been chosen as a material that allows exposed internal finish at varying composition, two chosen compositions are shown on diagrams below.
Shadow gaps finish for better acoustics
Staggered planks finish
Detail model at 1:10 sketched over
Perpendicular connection, floor to wall - butt joint
Wall panel connection, inner walls - half-joint
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Integration 1:40 typical detail
1:10 detail
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2
110 Ă— 40 mm Accoya planks, forming a ribbon, tightened together with 10 mm stainless steel rods
From right to left: 500 Ă— 1000 mm Panels of treated copper, 1mm thick, held by stainless steel brackets; 20 mm Plywood; 150 mm Cellulose insulation, raised 230 mm above the ground level; 140 mm Brettstapel structural wall, open finish on the inside
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1
2
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From top to bottom: 20 mm Brimstone Ash parquet (Brimstone wood), local and fast-growing; 75 mm Screed with underfloor heating; 200 mm concrete cast in-situ; Vapour Barrier; 360 mm Perlite insulation; Waterproof Membrane; 200 mm compacted hardcore, made with crushed bricks from the demolished building
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1:5 detail
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From top to bottom: 32 × 50 mm Accoya decking; Breather Membrane; 20 mm Plywood; 300 mm Fibreboard insulation, tapered at 1:50; Vapour control barrier; 220 mm Brettstapel - douglas Fir soft wood planks with 28 mm Hardwood dowels
From top to bottom: 20 mm Brimstone Ash parquet (Brimstone wood), local and fast-growing 75 screed with underfloor heating; 220 mm Brettstapel - douglas Fir soft wood planks with 28 mm Hardwood dowels
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Stainless steel drain covered with a steel mesh (Aco)
8 1 mm Copper sheet at 5° to allow water runoff; 150 mm deep concealed gutter with 75 mm Water membrane overlap
ADS 70 HI 2 Schnitte Door (Schüco) with Concealed Hinges 32 × 50 mm Accoya decking
25 mm Thermal break connection, steel to timber (Schöck)
Blockwork, tapered at 10° 37
Integration 1:20 typical detail
From top to bottom: 1:5 detail 500 × 1000 mm Copper sheets, 1 mm thick; Breather Membrane; 20 mm Plywood; 300 mm fibreboard insulation, tapered at 3°; Vapour control barrier; 220 mm Brettstapel - douglas Fir soft wood planks with 28 mm Hardwood dowels
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FW 50+ SG Structural Glazing (Schüco), stainless steel retaining clips, aluminium retaining clips and clip rosettes 6 6
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1:5 details
From top to bottom: 32 Ă— 50 mm Accoya decking; 38 mm Timber battens, nailed to Accoya decking from underneath; Waterproof Membrane 20 mm Plywood
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Alluminium frame, protecting rigid water-proof Perlite Insulation 9 From top to bottom: Accoya timber decking; Pavement stone; 50 mm Sandbed; 100 mm Compact hardcore
From top to bottom: Stainless steel bracket, holding Accoya ribbon up; 15 Ă— 250 mm Pavement stone; 50 mm Sandbed; 100 mm Compact hardcore 39
Design Legislation and Codes
Reflection
Starting looking into design legislation at the initial stage of the scheme development felt like a good idea but the crucial thing was to keep looking back in order to make sure that the design complies with the regulations at various levels. In terms of Part L that I have not looked into with much detail, it was only the U values that have been examined retrospectively. I found out that Brettstapel needs a thicker wall to achieve the same U values that may be obtained using other timber frame systems with equivalent insulation materials in thinner walls (Woodknowledge Wales, 2013) which meant that U values for the wall did not meet the requirement outlined in the Legislation.
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Research Part B (Volume 2) - Fire safety
Limitations on travel distance
Design for Horizontal Escape clearly states the maximum distances one can travel in case of emergency. For the use, proposed in the scheme, 45 meters, considering that escape is provided in more than one direction. In addition to that, inner rooms should be entered directly off the access room and not via the corridor (2007, p. 34). A number of escape routes relates to the number of persons using the space. Alternative routes of escape are counted as available in case of the angle being equal or more to 45° - as shown on the diagram below. Max number of people
Min number of escape routes
Approved Document B (Fire Safety) Paragraphs 3.8 and 3.9
Approved Document B (Fire Safety) Paragraph 3.2-3.6
Part L2A - Conservation of fuel and power
Limiting fabric parameters
There is a requirement for the maximum Carbon emission (TER - Target CO2 emission rate) which is linked to U values that have to be calculated in order to show that the building is compliant with the Part L.
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Part K - Protection from Falling, collision and impact Key areas that were looked at in this document have been required dimensions for the stairs - risers and goings, handrails, lengths of flights and landings. Stair nosing requirement and dimensions have been learnt at the RIBA CPD Roadshow (2019) on Stairway Safety from Quantum Flooring Solutions.
Rise
Change of direction is required if stair have more than 36 risers, as shown on the diagram below. In addition to that, for buildings other than dwellings having one riser is not allowed. General access stairs should not exceed 12 risers, while utility stairs could be 16 risers, if necessary (2013, p. 9)
Approved Document K (Falling, collision)
Approved Document K (Falling, collision) Paragraph 1.17 and 1.20
Approved Document K (Falling, collision) Paragraphs 1.11 and 1.34-1.35
Part M - Access and Use of Buildings
Accessible WC and external stair dimensions
Going
Headroom and handrail dimensions
Making sure that all spaces are accessible for all is a key aim of he Approved Document M (2015) which has been created as a response to Disability Discrimination Act (1995) which was primarily focusing on wheelchair users and physically impaired users. It covers wheelchair accessible toilet dimensions, clear entrances, limits of ramp gradients as well as external stair dimensions that would make access onto the site and into the building easy and accessible for people with various mobility needs. Level access, level thresholds and manifestations s something looked at in the Document M to make sure they are visible, accessible and clearly signed.
Approved Document M (Access and Use)
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Integration Part B (Volume 2) - Fire safety
Fire stairs and refuge points
Circulation inside the buildings has been made clear and legible for all visitors, including those with visual and mobility impairments by incorporating lifts and clear differentiation of colour in the stairs and at changes of level.
Refuge points (900Ă—1400 mm) inside the fire protected stair area is provided at all levels to allow wheelchairs to wait for rescue safety in case of fire emergency
The fire escape stair as located at the end of each wing, making the farthest travel distance in case of emergency not exceed 45 meters, considering that more than one direction of escape is provided, which is compliant with Part B, horizontal escape (HM Government, 2010).
Circulation
Fire stairs and exist in plan
There is a clear distinction of areas inside each of the buildings that mirror each other in overall layout.This also makes buildings more energy efficient - this is explained more in depth in the following section on energy use.
Services Circulation
Fire Assembly point
Fire Assembly point
Activity
Activity Circulation Services
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45 meters distance
Part K - Protection from Falling and Impact All stairs in the building, including the utility stairs and the main circulation stairs have been designed in compliance with the current regulations, making sure that they are accessible, comfortable to use and safe.
Central stair at 1:20 @A3 900 mm
300 mm 3000 mm
250 mm
Nosing design 150 mm
Nosing from Quantum Flooring Solutions have been chosen due to a number of reasons • Using 100% recyclable materials • Have photo-luminescent finish that allows the stair to be seen when it is dark • Slip resistance considered - particularly important in the outdoor areas • Designed in accordance with Part K, Part M and BS8300-2 regulations with accessibility for all in mind Stairs at 1:2
55 mm
300 mm
1900 mm 12 consequative risers
35 mm
1600 mm 2700 mm
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Integration Part M - Access and Use of Buildings
Entry points
Making sure that the site and the building is accessible for wheelchair users was essential to the development. The building was kept level where possible, with moveable platforms incorporated at two small level change instances due to the topography of the site. It was made sure that access in and out of the building is accessible for all and is visually clear. Moveable platforms at inner level change Lifts ensuring equal access to all spaces
The only entrance onto the site that includes stairs that, however has an alternative
Level change Access routes onto the site Key entrances into the building Additional entrances
1900 mm level change 46
Part L2A - Conservation of fuel and power
U value calculations
Composition
Conductivity (W/mK)
U values (W/m²K)
Part L requirement
1.6 W/m² K According to window specification (Schüco, 2019)
2.2 W/m² K
0.44 W/m² K which is higher than the required number but would vary from one area to another due to different wall thickness and types of insulation
0.35 W/m² K
Curtain walling Curtain walling: FW 50+ SG Structural Glazing (Schüco)
External wall External wall from right to left: 1 mm Panels of treated copper;
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20 mm Plywood;
0.8
150 mm Cellulose insulation;
0.25
140 mm Brettstapel structural wall, open finish on the inside
0.16
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References Accsus Technologies (2012) Structural Design Guide to EuroCode 5 [online]. 3 August 2012. Retrieved from https://www.trada.co.uk/media/3572/structural-design.pdf. [Accessed 26 March 2019]. Accu Grafisch Ontwerpers (2013) Reef Bench. [online]. Retrieved from: http://www.remyveenhuizen.nl/work/public-space/reef-bench. [Accessed 10 March 2019].Natural Resources Wales (2019) Coed-y-Brenin Visitor Centre. Architype [online]. Retrieved from: https://www.architype.co.uk/project/coed-y-brenin-visitor-centre/. [Accesseed 4 April 2019]. Brettstapel.org (2015) Brettstapel Manufacturers. [online] Retrieved from: brettstapel.org/Brettstapel/Manufacturers.html. [Accessed 16 February 2019]. Copper Life Cycle (2012) The environmental profile of copper products. 4 July 2012. Belgium: European Copper Institute. Copper Concept (2006) The Guide to Copper in Architecture. November 2006. Retrieved from: https://copperconcept.org/en/file/1593/download?token=ej9Q3wHD [Accessed 11 March 2019]. Demir, I., Başpınar, S., and Kahraman E. (2018) Production of Insulations and Construction Materials from Expanded Perlite. Proceedings of 3rd International Sustainable Buildings. pp.24-32. Turkey: Metallurgy and Material Science Engineering Department, Faculty of Technology. Department for Business innovation and skill (2010) Estimating the amount of CO2 emissions that the construction industry can influence. London: The Stationery Office. Gordon, A. I. (2015) Finite Element Analysis of Connections in Dowel Laminated Timber. MEng Thesis. [online] Retrieved from: https://issuu.com/alistairgordon/docs/a.gordon_ meng_thesis. [Accessed 16 February 2019]. Halliday, S. (2015) Sustainable Construction. 7 November 2015. Retrieved from: https://issuu.com/thanhcn/docs/sustainable_construction. [Accessed 16 February 2019]. HM Government (2010) The Building Regulations. Fire Safety. Approved Document B. April 2007. London: HM Government. HM Government (2010) The Building Regulations. Protection from Falling, Collision and Impact. Approved Document K. 2013 ed. London: HM Government. HM Government (2010) Conservation of fuel and power. Approved Document L2A. London: HM Government. HM Government (2010) Access to and use of buildings. Approved Document M. 2015 ed. London: HM Government. John Cullen Lighting (2019) Designing with Light [RIBA CPD Roadshow]. Bristol. 10 April 2019. Latham, J. (2019) Accoya: Sustainable High Performance Wood. [online]. Retrieved from: http://www.lathams-accoya.co.uk/. [Accessed 12 March 2019]. MACH Products (2017) Natural Ventillation without Noise. Natural Ventillation Series. [online] 11 October 2017. Retrieved from machproducts.com [Accessed 2 April 2019]. MoveArt (2019) BURRI moveart - Playing bench «family». Retrieved from: https://www.burri.shop/en/BURRI_moveART__Playing_bench_family.a4605.2.html. [Accessed 10 April 2019]. Pearce, D. (2009) Is the construction sector sustainable? Definitions and Reflections. Building Research & Information. 34 (3). pp. 201-207. Quantum Flooring Solutions (2019) Step on it: Stairway Safety [RIBA CPD Roadshow]. Bristol. 10 April 2019. Schueco (2019) Products: FW 50+ SG. [online]. Retrieved from: https://www.schueco.com/web2/uk/specifier/products/facades/structural_glazing_facade/schueco_ fw_50plus_sg. [Accessed 26 March 2019]. Smith, S. (2013) Solid Wood Solutions [Interview]. (23 February 2013). Structure Craft (2017) Dowel Laminated Timber. The All wood panel. Mass Timber Design Guide. 3 November. Retrieved from: https://structurecraft.imgix.net/assets/img/ materials/StructureCraft-DLT-Design-eGuide-V3.pdf [Accessed 16 February 2019]. Structure Craft (2018) Michael Green Talk – The Future of Wood & Dowel Laminated Timber. Vimeo. Retrieved from: https://vimeo.com/248180026. [Accessed 16 February 2019]. Sust.Architecture + Design Scotland (2011) Material Considerations. Case Study: Acharacle School. Retrieved from: https://www.ads.org.uk/wp-content/uploads/04_AcharacleSchool.pdf. [Accessed April 13 2019]. Williams Homes LTD (2016) Low Carbon Construction. Retrieved from: http://williams-homes.co.uk/index.php/about/. Accessed 10 March 2019]. Woodknowledge Wales (2013) Welsh Softwoods in Construction. October 2013. Retrieved from: http://bc.bangor.ac.uk/news-and-resources/news/documents/ WelshSoftwoodsinConstructionReportNov13.pdf. [Accessed 28 January 2019]. World Green Building Council (2019) Better Places for People. [online] Retrieved from: https://www.worldgbc.org/better-places-people. [Accessed 14 March 2019].
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Confucius Institute Redcliffe Wharf Bristol Anastasia Angeli
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