Design and Specification Issues

Contents

• Strategic issues
• Adaptability and flexibility of use
• Social issues
• Economic factors
• Operational construction issues
• General issues: Adaptability
• Construction planning and logistics
• Materials
• Methods of construction
• Material efficiency and waste
• Waste management in use
• Waste hierarchies

Strategic Issues

• Moving sustainable -design towards greater commercial feasibility
• Applying existing sustainability standards in a coherent ‘one stop shop’
• BREEAM, Offices, Retail warehouses, Industrial, Retail developments,
Code for Sustainable Homes
- Apply principle to all buildings in the absence of a formal scheme
- Since a ‘Pass’ can be achieved for no financial outlay and is easy to achieve always aim for ‘Excellent’ or higher
- Choice of materials to achieve Code for Sustainable Homes rating is on an ABC scale A being the best, but it only classifies the greener end of conventional materials available and the scope does not address many sustainable, renewable, natural, recycled materials.

Adaptability & Flexibility of Use

Lifetime Homes:
• Accommodate changes in families from young couple, add children and into old age
- Model: Greenwich Millennium Village housing flat layouts, slide away walls between bedrooms and living rooms, allow opening up of the house during the day
- The Garston Integer House has partitions between two bedrooms hung on tracks to allow lateral movement to change room sizes
• Provision or adding or updating new technology in the future:
- Model Integer House: services run behind removable skirtings to allow rapid rewiring or additions of services
- BedZED services run behind hollow skirtings, dado, movement joint covers
• Access and independence: Controls (disabilities)
- Door openings minimum 900 mm. corridors minimum 900 mm
- Flush threshold front and rear. BRAD M Toilets
• Positive approach: do not over design to meet specific requirements of the brief that if the Client moves out the building become redundant because no other users can occupy the building
• A poor response: design an ice rink as a factory to revert to a factory use if the Ice Rink use fails

Social & Health Issues

• Privacy and community
• Health and safety
• Poor indoor air quality if high performance windows and doors and airtightness improvements without adequate ventilation
• Build tight, Ventilate right
• Choice of materials: Low VOC paints and other materials, less solvent based paints, but more importantly more natural, less synthetic
• Children’s play and interaction
• Noise impact
• Daylight
• Housing: Secured by Design (Police Commissioners)
• Building for Life
- Access and independence: Controls (disabilities)
- Door openings minimum 900 mm. corridors minimum 900 mm
- Flush threshold front and rear
- BRAD M Toilets with grab bars

Economic Factors

• Lean Construction seeking efficiency and waste reduction in all management activities
• Co-ordinated Project Information to minimise Quality Related Events and reduce defects and waste
• Reduced running costs (Energy & Utility services)
• Retire to no domestic services bills
• Understanding whole life costing
• Integrating Best Value approach
• Supply chain management addressing: materials choices, minimising packaging waste, take-back schemes for packaging and materials, use or return to stock, uses of recycled materials
• Local sourcing reducing transport miles for materials
• Consider secure external storage provision for Internet shopping anytime delivery

Operational Construction Issues

• Soil/ground conditioning.
• Impact on neighbourhood, adopt Considerate Contractor Scheme methods.
• Waste minimisation and management.
• Recycling paper and segregating plastic bottles and tin cans etc.
• Transport movements and waste.
• Efficiency in mass production of hot food.
• Efficient waste management in kitchens and food areas.

General Issues: Adaptability

• Set out to achieve consistent component life equal to design life.
• Design a long life durable structure with replaceable shorter life building fabric and secondary components.
• Design shorter life components to be robust enough to dismantle and reassemble.
• Allow for sizing and operation of current and foreseeable lower carbon energy systems and appliances.
• Renewable compliant or renewable ready:
- Make provision for additional services in future, on roofs, in the structure, roof upstands, etc.
- Design easy access to services to allow simple additions or replacement of system wiring.
• Specify reversible fixings for internal walls, fittings and services.
• Specify layering of building and services to minimise penetrations through vapour barriers, air tightness layers, damp proof membranes and gas proof membranes, thermal and acoustic insulation, etc.
• Specify modular components and make assemblies multiples of units.
• Specify easily replaceable external wall components: Segal method.
• Explore use of wireless technology for some systems. (Caution: CDM: Radiation).

• Draw on:
- Greenwich Millennium Village, which: revisited 1956 Parker Morris Standards for Housing (set minimum standards for house, room and storage floor areas); included moveable internal walls – reduces need for extensions, improves quality of life;
- Used Lifetime Homes standards (adaptability through whole life of family through 3 generations).
- Integer House Projects: services run behind skirtings fixed for easy removal
300 mm. wide doors into services ducts to allow access for adaptation and additions.
BS 7543:1992:Guide to durability of buildings and building elements, products and components.

• Component Life Manuals:
- HAPM Component Life Manual (published by SPON).
- Building Performance Group Building Fabric Component Life Manual (published by SPON).
- BLP Services Component Life Manual (published by Blackwell).

Construction Planning and Logistics

• There is a big potential obstacle to our minimising carbon approach:
- To lower embodied carbon we may need to source emerging products which are only available from abroad.
- This pushes up carbon significantly and, in our terms, unsustainably.
• A robust methodology is needed to assess the carbon emissions of any action carried out on the project – an applied and flexible Life Cycle Assessment for buildings.
• Offsite prefabrication and use of standard size components to minimise waste.
• Store materials to prevent deterioration and unused materials for snagging, 12 month defects inspection and ongoing FM maintenance of building.
• Return of palleting and packaging to manufacturer or third party specialist.
• Segregation of waste to allow return to manufacturer under take-back schemes.

Materials

• Increase the use of the following:
- Product quality marks (BSI Kitemark, BBA, etc) 3rd party accreditation.
- Durable materials, long component life.
- Recycled primary materials.
- High recycled content.
- Use of materials made from secondary materials: aggregates.
- Reuse and recycling of construction or demolition waste.
- Natural and renewable materials (wool, timber, non-food crops, etc.).
- High Natural content.
- Manufactured renewables (e.g. biopolymers, biotechnology-manufactured materials).
- Appropriate advanced materials e.g. self compacting concrete.
- FSC certified timber sources and timber based materials, See Z10.
- FSC Chain of custody from forest to site. See Z10.
- ZODP Zero Ozone Depleting Potential materials, See Z50.
- Reduced carbon impact as well as ozone and health benefits.
- Low Greenhouse Gas Potential materials, (reduced carbon impact as well as ozone and health benefits)
- Use of materials with Hygroscopicity, for less risk of condensation and degradation due to moisture, and no loss of performance if wet or in humid conditions.
- Life Cycle Analysis and Costing
- Use of on-site as-found Materials
- On site storage for excess for future maintenance
- Allergy free materials
- Toxicity-free materials

Reduce use of the following:
- Fossil fuel-based materials, petrochemicals, plastics
- Materials containing halogens, formaldehydes and other VOCs, See Z12 and M60
- Materials containing Chlorine, PVC, CFC, HCFC, HFC, CPE, See Z50
- PVC (Polyvinylchloride) See Z50
- CCA (Copper Chrome Arsenic)(Report on CCA from NZ .pdf) Treated softwood, See Z12
- Creosote treated timber See Z12
- Deleterious Substances listed in European Waste Catalogue See A38 APP

Methods of Construction

• Offsite prefabrication: construction industry skills shortage can be ameliorated by more factory production.
• On-site temporary factory production, benefits: less vehicles to deliver materials, aiming for factory conditions and better quality work and less waste.
• Set up on-site factory production under weatherproof enclosure on solid base and thermally comfortable conditions.
• Use of standard size components without cutting, to minimise offcuts and waste.
• Balance with avoiding transporting large volumes of air.
• Panelisation in preference to volumetric, unless fully equipped and heavy.
• Airtightness layer, Breathing wall, hygroscopicity, moisture uptake and release.
• As opposed to vapour resistant barrier, punctured by services, vapour transfer, susceptible insulation, water held against timber sections and breather membrane.
• Breathing walls and roof construction acknowledged and confirmed by BRE.
• Layering of building and services to avoid complexity and puncturing of DPC, DPM, GPM, VB, BM, ATL, etc.
• Making assemblies multiples of units, minimising waste, using left over pieces until all gone.

Materials Efficiency and Waste

• Design to reuse second hand reclaimed materials: find the materials then design the building around them
e.g. Steel in Doncaster’s Earth Centre Roofs, by Bill Dunster.
• The total CO₂ created by making materials for a building can be reduced by reuse and recycling materials.
• Avoid materials that downcycle as opposed to recycle: e.g. PVC’s properties change in reprocessing so Virgin PVC must be used or recycled PVC has limited application.
• Steel normally contains a high percentage of scrap added in smelting process and can be reprocessed into same grade of steel.
• Design to minimise waste: acknowledge the manufacturing size when designing components and assemblies.
• Acknowledge brick sizes when designing wall lengths, same applies to blockwork and timber constructions.
• Ensure the design of a building accommodates easy storage of separate recyclate, easy composting routes (e.g. direct exit from kitchen worktop to external composting system for organic green waste).
• Design for low cost, efficient deconstruction.

• Consider compatibility of material mix, to increase quality of ‘deconstructed’ materials for re-use or recycling purposes.
• Avoid polymer migration between plastics.
• Minimise use of composites that are difficult to separate, this applied to packaging too.
• Deconstruct not demolition:
• Assemble steel framed building with clamps and bolts in preference to welding, this permits a degree of off-site prefabrication and simple on-site work.
• Assemble timber buildings with bolts, screws and other fasteners in preference to nailing and adhesives.
• Assemble with locational methods of assembly, e.g. Insulation squeeze insert release.
• Assemble using ballast in preference to fastenings and adhesives to allow the building to be deconstructed, and components to be used again. E.g. waterproof membranes.
• Design for deconstruction and reuse: avoid welding, adhesives and nails; use, clamping, bolting, ballast and screws.
• Enable product-purchase to become function-purchase – e.g. very low cost leasing of mechanical or electrical systems and heating appliances; maintains optimum efficiencies and therefore lower carbon emissions through appropriate servicing, and reduces capital costs, enabling operational savings to pay for higher cost of environmentally-better equipment.

Waste Management in Use

• See R31 for more detail.
• Waste segregation at the kitchen sink.
• EcoHomes: Minimum 3 bins: under kitchen sink and 3 bins outside.
• Compostable, Recycleable & Waste.
• Waste segregation bins and temporary storage.
• Composting for soil improvement.
• Vertical home grown food.
• Offsite segregation is possible with the right partnering, at segregation and bulking sites.

Waste Hierarchies

The waste emanating from UK construction sites is huge - between 36 and 40% of all materials delivered to building sites leave in mixed skips. See A38 and for more detail.

• Refuse :
- Unnecessary, excessive, complex or all packaging and protection. Supply chan management - forming partnerships can offer opportunities to demand better services from manufacturers.

• Reject:
- Defective materials should be replaced by the manufacturer at their expense.

• Return:
- Sale or Return ensures that over-ordered and unused materials can be taken back into stock if unused.
- Take-back schemes are emerging for the return of waste or end-of-life materials can be returned to the manufacturer.

• Redesign to reduce:
- Reduce off-cuts by designing to manufactured sizes.

• Reduce Demand:
- Don’t over-design structures.
- Design to reduce the quantity of materials.

• Reuse:
- Reuse materials from demolished/refurbished buildings. Bricks and doors continue to be bricks and doors.

• Reclaim:
- Salvage and reuse demolition and construction materials.

• Retain:
- Retain unused materials for Reuse/Repair.