Repurposing structural timber in a circular economy.
Are you looking to re-use, re-purpose or recycle existing timber, how do you know it is fit for purpose?
We test and visually grade timber on your building site, in a factory or shop and certify its structural grade, providing Evidence of Suitability for your Engineer or Certifier.
Turn used or existing timber into Certified Structural Performance.
Don’t risk using an existing timber beam with out a current Grading Certificate, know that it is Fit for Purpose before you buy, re-use or even salvage it.
Re-timber locks in the stored carbon of the existing timber for additional years of service (saving another tree) and allowing the beauty of re-purposed timber to tell its story again.
Re-purposed timber has a density and seasoned stability un-matched by new growth plantation timber.
In the construction industry, the phrase “Fit for Purpose” carries significant legal weight and obligations.
Under the National Construction Code (NCC) ensuring that a building material, design, or assembly is fit for purpose is the pathway to achieving a Certificate of Occupancy.
What Does “Fit for Purpose” Actually Mean?
A material, product or system is considered fit for purpose if it satisfies the NCC Performance Requirements relevant to its use;
It must perform the function it was designed for;
A shower enclosure must be watertight.
A timber beam must resist loads its designed to.
A habitable room must be ventilated to achieve a certain internal air quality.
It must be durable enough to last its expected service life.
It must comply with relevant Australian Standards referenced in the NCC.
Evidence of Suitability (NCC Part A5)
You cannot simply “claim” a product is fit for purpose. A building certifier requires Evidence of Suitability to verify compliance. This typically includes:
CodeMark/WaterMark Certification, high-level certificates that prove a product meets NCC requirements.
Test Reports, results from accredited laboratories (NATA) proving the material passed specific fire, load, or acoustic tests.
Certificate or Report from a professional engineer or other appropriately qualified person, certifies a material, product or form of construction fulfils specific requirements of the BCA and sets out the basis on which certification is given.
Product Technical Statements, detailed data sheets from manufacturers.
The Certifier’s Perspective
A certifier’s role is to mitigate risk. To satisfy a certifier “Fit for Purpose” must be documented. They look for:
Compatibility, does the material meet the design specifications?
Installation Compliance, was the product installed according to the Australian Standards or manufacturer’s instructions? Even a “fit” product becomes “unfit” if installed incorrectly.
Traceability, documentation that proves the material installed on-site is compliant.
The Engineers Expectation
The Engineers role is to provide the scientific proof that a building will perform as intended. They:
Ensure structural integrity, calculating loads (live, dead, wind, snow) to ensure the building doesn’t fail.
Specify materials, assuming they will perform to a certain strength grade or have certain properties required by the design.
System design, designing complex mechanical, fire safety, or hydraulic systems that must integrate seamlessly with the architectural plans.
Risks of Non-Compliance
Using non-conforming building products or failing to prove suitability can lead to:
Order to Remove, a certifier can refuse to accept, forcing expensive rectification work.
Insurance Voidance, many policies will not cover failures caused by non-fit-for-purpose materials.
My original thoughts were cool we can take materials to a manufacture/drop off point and provide them with not quite raw materials but essentially the same thing, their costs go down, we don’t have to pay high tip fees, everyone’s a winner.
How wrong (or naive) was I…
The concept of a Circular Economy is recycling on steroids, but more about – we are going to run out of land fill sites, essentially storage of our waste as a state/country/world, so what are we going to do with it?
There are definitely benefits to a Circular Economy;
Use reclaimed/repurposed/recycled materials (less landfill, less embodied energy)
Supply chain (available materials)
Design for disassembly, modular construction (MMC)
Cost reduction is definitely NOT one!
After letting this cook for a while I reckon it comes down to three things;
The definition of “Waste”, its more complex than you think (definitely for the lawyers)
Fees or Waste Levy, a $ amount you need to pay to government for producing waste (hence the definition)
Scale (are we talking a few lengths of timber on your roof racks or a yard with the ability to process thousands m3 of timber per year)
So, to the definitions;
Waste includes –
any substance (whether solid, liquid or gaseous) that is discharged, emitted or deposited in the environment in such volume, constituency or manner as to cause an alteration in the environment, or
any discarded, rejected, unwanted, surplus or abandoned substance, or
any otherwise discarded, rejected, unwanted, surplus or abandoned substance intended for sale or or for recycling, processing, recovery or purification by a separate operation from that which produced the substance, or
any processed, recycled, re-used or recovered substance produced wholly or partly from waste that is applied to land, or used as fuel, but only in the circumstances prescribed by the regulations, or
any substance prescribed by the regulations to be waste.
A substance is not precluded from being waste merely because it is or may be processed, recycled, re-used or recovered.
Short version, if you no longer want it on your site and intend to remove it, it is most likely waste. If it is waste then you guessed it, fees apply.
If you produced waste, then you pay fees no matter if it being recycled or going to land fill.
From NSW Environment Protection Authority – Guide to the NSW Resource Recovery orders and exemptions policy framework
In the figure above fees become applicable some where between “Reuse waste” & “Recycle waste”.
So how is it Reuse? – Good question and no I am not joking
In NSW, whether a substance is considered “waste” depends significantly on the state of mind of the original owner (the intent). If you, as the original owner, view a substance as unwanted, surplus, rejected, or abandoned, it is classified as waste under the Protection of the Environment Operations (POEO) Act 1997.
Key Factors;
Original Owner’s Intent (state of mind)
Unwanted or Surplus, its waste (even if someone else can use it)
RecyclingIntent, separate operation – its waste (only ceases to be waste once it has been substantially reprocessed)
Reuse Intent if original owners plan was to reuse, it was reclaimed in an appropriate way (little damage), requiring little to no process for it to be in its original state or purpose , then it is possibly not waste depending on your state of mind
Environmental Impact if when exposed in the environment it causes pollution
Lawful Disposal you can only transport waste to a place that is lawfully authorised to receive it i.e. a place with an Environment Protection License (EPL) = Fees
Stockpiling Temporarily storing unwanted material on your land can trigger “waste storage” licensing requirements = EPL = Fees
Scale, if you want a lot gone its waste, the ability to go and drop off a large amount of material will definitely be considered waste (unwanted/surplus/ requires recycling, processing or purification), if where you take it has a lot of it – its stockpiling (EPL)
Sorry, I can’t stop thinking “government needs to clip the ticket on the way through”.
Call or email, We can chat about what you need and how we can help
If you are a Builder who needs help with;
Passive House Principles
How to look at the job and think “Passive House”
Installation details
Window installation
Weather Resistant Barriers (WRB)
Internal Air Barriers (IAB)
We can help you. We talk thorough details & options prior to construction, plan your membrane layers, work with you to install and test before we leave site to ensure airtight buildings
It is very important to talk to us before you start construction to achieve your ACH goal without excessive costs and re-work.
We don’t just give you a detail and say good luck, we are hands on and work with you to get framing details right, with no added delays or complexity, so you can keep building.
Passive Performance, blends the art & science of airtight systems, We;
Detail & explain elements to reduce issues with air barriers & thermal bridging in the design
Dynamic Simulations: WUFI performs dynamic simulations of coupled heat and moisture transfer, providing realistic results under actual climate conditions.
Comprehensive Modeling: It accounts for vapor diffusion, capillary transport, sorption, and weather conditions like rain and solar radiation.
Risk Assessment: The software helps assess the risk of moisture accumulation, which can lead to mold growth and structural damage.
Material Properties: It uses standard material properties and easy-to-determine moisture storage and liquid transport functions.
Applications:
Building Design: Used by architects and engineers to design buildings that are energy-efficient and moisture-resistant.
Wall & Roof construction methods: Helps designers & builder test or confirm the performance of proposed construction methods.
New Homes & Renovation Projects: Assists in evaluating the hygrothermal performance of buildings allow strategies to avoid condensation and mould risk.
Would you like to know more about how WUFI analysis can be applied to your project? Contact us!
Hopefully this is educational so you can use as a reference to determine what is best for your situation.
With the increasing building regulations and changes in the Building Code, we thought it was timely for a discussion on what it all means. Different people/different terminology, they get called water control layers, pliable building membranes, wraps, sarking, weather resistant barriers WRB.
If we start with the NCC or Building Code 2022;
Building Code – Volume 1 2022
F3D3 Sarking – refers you to AS 4200.1 & AS 4200.2.
F8D3 External wall construction – pliable building membrane, talks about the AS, location, permeability, potentially a drained cavity, material open or closed to vapour & reflective wraps must have an air gap.
Building Code – Volume 2 2022
H1D7 & H2D6 Roof and wall cladding – refers you to the Housing Provisions
H1D9 Condensation management – refers you to the Housing Provisions
Housing Provisions 2022
7.5.2 Timber wall cladding (3) (c) compliance with AS 4200.1
10.8.1 same as F8D3 above
Terminology;
Air control membrane: A membrane installed to limit air transfer between each side of the membrane.
Primary insulation layer: The most interior insulation layer of a wall or roof construction.
Pliable building membrane: (from the BCA) A water barrier as classified by AS 4200.1. (from AS 4200.1) A material that is able to be folded back on itself without causing structural damage to the product that effects its material properties.
Thermal control membrane: a membrane with a surface emissivity (reflective insulation) and/or material R value (bulk insulation) intended to reduce heat transfer.
Sarking-type material: A material such as a reflective insulation or other flexible membrane of a type normally used for a purpose such as waterproofing, vapour management or thermal reflectance.
Vapour control membrane: a pliable building membrane designed to either allow or restrict the transfer of water vapour across the membrane.
Vapour permeance: The degree that water vapour is able to diffuse through a material, measured in μg/N.s and tested in accordance with the ASTM-E96.
Water control membrane: a membrane intended to collect and discharge any water that penetrate a building envelope or cladding.
AS 4200.1 Pliable building membranes and underlays;
Classifies membranes in several categories to ensure they are “fit for purpose” or suitable for the intended application.
Emmitance classification, (or how reflective the product is)
IR Reflective has an emittance of ≤ 0.05
IR Semi-reflective has an emittance of > 0.05 to ≤ 0.15
IR Non-reflective has an emittance of > 0.15
Vapour control classification, (how easy water vapour can pass through), permeance measured in μg/N.s which is micrograms of water passing through a material per Newton second of force applied
Class 1 – Vapour barrier – 0 to <0.0022
Class 2 – Vapour barrier – 0.0022 to < 0.1429
Class 3 – Vapour permeable – 0.1429 to < 0.1403
Class 4 – Vapour permeable – 0.1403 to with no maximum
Water control classification, tested in accordance with AS/NZS 4201.4
Water barrier (it passed the test)
Non-water barrier (it failed the test)
Flammability classification, tested in accordance with AS 1530.2
Low, a flammability index ≤5
High, a flammability index >5
Air control classification, (how air tight or resistance to air passing through it a product is) tested in accordance with ISO 5636-5
It is important to note, you cannot stop condensation from occurring, you can take steps to reduce the likelihood of it occurring and plan to manage it with drainage & ventilation to assisting in drying out the materials to avoid mould and decay in your home.
So, the climate will determine the location of the wrap, membrane, control layer etc. we want to use these materials to either prevent passage of air or maximise the potential of it occurring, we don’t want to use materials that are not compatible (say a permeable wrap with impermeable insulation or sheathing board).
Remember;
Vapour control: usually a product that inhibits vapour movement to stop vapour from the outside.
Vapour permeable: to facilitate vapour movement from the inside to help dry the building out.
Thermal control: to keep things warm and not reach dew point temperature.
Air control: vapour is airborne moisture, hence if we control air movement we can prevent vapour getting into our walls & roofs to reduce the likelihood of interstitial condensation.
Controllable ventilation: can assist in removing vapour if used appropriately.
Smart or Intelligent membranes: that can restrict or facilitate the flow of vapour.
The Building code talks about these concepts, some things are mandatory, some are only if you install etc.
The proposed 2025 building code considers a requirement for a drained and ventilated cavity if you don’t have a control layer. If it’s your licence or reputation I would suggest planning for control layers and a drained and ventilated cavity.
What products are available and their characteristics, we have produced a list of materials for you to review & consider if correct for your application.
Who is involved in the process of designing, specifying and building?
Building Designer
Passive House Consultant
NatHERS Assessor
Blower Door Tester
Builder
Carpenter
Ask them some questions about any of the above and see what they say, they may have an excellent understanding or may be new to risks associated with where the Building Code is taking us.
If you don’t get the responses you were expecting contact us to help you with your project.
So what would we do or recommend;
The answer is “well that depends on”
What climate, what construction methods & materials, how you plan to manage condensation, the strategy you will implement, the budget, ventilation provided.
