G20 Carpentry Timber Framing First Fixing (Checklist) G#1597 N#1527

By July 26, 2014July 10th, 2019Checklist, Code, Encyclopaedia, New Build

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G20 Carpentry/Timber Framing/First Fixing Checklist

G20 Carpentry/Timber Framing/First Fixing Checklist
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Index:


Problems:

  • Tree cutting is seasonal:
    • unseasoned hardwood framed buildings:
    • be aware of the potential for delay until next tree cutting occurs,
    • plan projects around this issue
  • Acidic species:
    • tanning run off can stain porous materials below,
    • provide temporary or sacrificial protective materials or coatings
    • can corrode or stain ferrous metal fasteners or visa versa
    • use austenitic stainless steel fasteners (screws/nails etc.)

Misunderstandings:

  • Durable timbers do not all come from the Tropical Rain Forests
  • There are durable softwoods as well as hardwoods
  • Prefabrication off site does not reduce offcuts,
    • but the off cuts have a greater potential to be used in a factory rather than put in a skip on site

Solutions:

  • Grow trees to be available to replace roof and other timbers in 60-120 years
  • Use any existing trees that are to be cut down as part of the works

Consider:

  • Choose locally sourced timber:
    • first > last:
    • Site > Town > County > Region > Country > Continent > World
  • FSC certified forest timber,
    • it addresses more of the sustainability issues,
    • 276 sources in the UK.
  • Oak and many other species are durable and are available in the UK and Europe
  • Off site prefabrication to reduce on site waste
  • Design structure for appropriate life See A90
    • Short life: 30 years
    • Normal Life: 60 years
    • Long life: 120 years:
  • Design frame for deconstruction, salvage and reuse in future at end of design life. See A90
  • Softwood or Hardwood in place of steel structure
  • Floor structure, roof frame, decking and ramps are opportunities for timber structures made from home-grown structural timber, reducing the need for cement and aggregates on the project
  • Glued laminated timber where poor strength grade timber can be substituted in the middle of the section where it is least stressed
  • Potential to reduce the self weight of the section without significant loss of strength
  • Use of prefabricated pre-insulated breathing wall, floor and roof panels
  • Timber structure in place of concrete
    • to avoid temporary formwork materials (plywood and softwood) used in formwork,
    • potentially used a few times then thrown away to landfill as waste

Avoid:

  • Wood substitutes: unless it is 100% recycled plastic
    • Cradle to Cradle:
      • avoid blending natural (wood fibre, wood flour) and technical (plastic binder)
      • ingredients that cannot be separated at end of life,
    • Proviso: unless the manufacturer:
      • leases the product to the user,
      • has a tack back scheme in place,
      • is already recycling their own post consumer product
  • Illegally forested timber
    • (Use EUTR procedures)
  • Non-sustainably managed forested timber
  • Tropical Rainforest timbers,
    • (there are probably other species which will do the job you need from nearer the site)
  • Endangered species of timber,
    • (Check the CITIES website)
    • See GBE SPECIES TABLE
  • Clear felled virgin forest timber
  • Clear felled plantations if not replanted
  • Indonesian Hardwood,
    • most is reported to be illegally logged:
    • destroys forests, communities and habitation
  • Adhesives if fasteners will do the job required
  • Burning timber off cuts on site

Minimise:

  • PEFC certified forest timber, it does not address all the sustainability issues adequately, choose FSC first
  • Synthetic adhesives if natural alternatives can do the job required

Substitute:

  • Specify by performance requirement then the suppliers can choose available FSC species to do the job required and offer a range of colours close to your requirements

Health:

  • Avoid formaldehyde adhesives in boards, compound or laminated sections See Z20

Wellbeing:

  • Use planed and arrised softwood sections to minimize splinters whilst handling sections

Safety:

  • Normal manual handling and mechanical handling safety measures
  • Bulk timber is heavy and has momentum at the end of a sling from a crane

Precautionary principle:

  • Use a sacrificial coatings during handling and installation
  • Sand off all sacrificial coatings prior to hand over leaving in pristine condition

Resource Efficiency Issues:

Reduce:

  • Use compound I section timbers, in place of solid sections:
  • reduces use of timber, resource use reduction
  • reduces fuel to transport
  • easier to handle on site, often by just one person

Reclaim:

  • All healthy timber that can be reused

Reuse:

  • Second hand timber
  • FSC now recognises reuse of timber
  • Salvaged timber from existing building in:
    • Softwood in stud walls, floors or roofs
    • Floor boarding
    • Doors, Windows

Recycle:

  • Damaged untreated timber
  • Make bat and bird boxes with offcuts
  • Use as mulch in landscape

Recover:

  • Nutrients from untreated timber by composting
  • Energy from timber offcuts by saving in a biomass fuel store for use in the employer’s biomass boiler

Waste Issues:

Hazardous waste & Deleterious Substances:

  • Preservative treated timber is hazardous
  • Do not use preservative treated timber in bat and bird boxes
  • Do not use preservative treated timber in childrens toys
  • Do not use preservative treated timber in food growing planters, raised beds
  • Preservative treated timber is potentially inert in landfill, but leaching may occur

Waste statistics

  • 30 m tonnes (33% of 90 m. tonnes/year) of waste is offcuts (not all timber)
  • 9.4 m tonnes (10.2% of 90 m. tonnes/year) of waste is Temporary works, Site hoardings and Formwork

Waste minimisation:

End of Life options:

  • Dismantle for reuse (build it with the right fasteners)
  • Choose durable species

Appropriateness:

  • off site prefabrication to reduce waste:
  • Use of prefabricated pre-insulated breathing wall, floor and roof panels

Competence:

  • Reclaimed timber for reuse:
    • check suitability for use in structural application
    • there are 900 timber strength graders in UK
    • some structural engineers will assess timbers for reuse
  • Choose species with the right properties for the job
    • Don’t choose your favorite coloured species for every application
    • Don’t choose your favorite coloured species for external applications the colour will fade to silver or grey

Effectiveness:

  • Steel sections can be smaller than timber to meet structural requirements
  • If fire resistance is required steel sections get considerably bigger than timber
  • Encasing steel or applying intumescent paint increases cost and environmental impact
  • Timber sequesters carbon from the atmosphere so reduced atmospheric carbon now
  • Timber buildings can be carbon negative

Yardstick:

  • A standard is being developed to permit embodied carbon and sequestered carbon to be taken into account in Total Carbon calculations for buildings

Maintenance issue:

  • Untreated unseasoned unfinished durable species timber need no decoration and need no maintenance of that decoration

Information sources:

  • The Wood Explorer(USA, part free, mostly paid for access, via apps)
    • A massive knowledge-based site featuring 1648 tree species.
    • TRADA
    • askTRADA

© GBE NGS ASWS BrianMurphy
aka BrianSpecMan
2008 – 25th July 2014 – 15th February 2018

G20 Carpentry/Timber Framing/First Fixing Checklist
Images:


STA CSW banner jpg

© Structural Timber Association


SWS Solid Wood Solutions Logo png

© Solid Wood Solutions


Timber Expo 2013 png


NGS Timber Species A02 BRM 190114 PNG

GBE DataSet
GBE Timber Species (Dataset) G#1371 N#1351

Avoid using the species in the pink rows


21TimberFrame.png

GBE CPD


If you wish to reproduce images, feel free, but please acknowledge the source.


© GBE NGS ASWS BrianMurphy
aka BrianSpecMan
25th July 2014 – 15th February 2018

G20 Carpentry/Timber Framing/First Fixing Checklist
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© GBE NGS ASWS BrianMurphy
aka BrianSpecMan
25th July 2014 – 15th February 2018