Author: admin_thermalperformance

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Circular Economy & Fit for Purpose

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;

  1. The definition of “Waste”, its more complex than you think (definitely for the lawyers)
  2. Fees or Waste Levy, a $ amount you need to pay to government for producing waste (hence the definition)
  3. 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)
  • Recycling Intent, 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”.

At scale this pdf demonstrates it wellDownload

Hang on, back it up…

I want to repurpose or reuse it;

  • At scale – see above, still waste
  • Single items or smaller groups of items, keep reading

If your intent was repurpose as a “second hand material” then it depends on the items and your ultimate goal for them.

In a circular economy, these are two distinct categories:

  • Intention was Reuse
    • If your goal was to prolong the life of an item/material
    • You demolish, reclaim, separate in a suitable manner, very little damage
    • Item/material requires no treatment and/or very little processing to return it ready for its original purpose/use
    • Yes, it is considered second hand, subject to factors above
  • Intention was Disposal
    • It is waste
    • If there is scale, unwanted, surplus, requires recycling, processing, its waste

So, if your goal is to resell, repurpose, reuse then make sure;

  1. Item is identified prior to demolition, stripping, separation
  2. You have given the item a value (monetary, sentimental, historical)
  3. Demonstrate you still want it, stored correctly etc.
  4. Don’t make a big thing of cutting it or pulling the nails out (processing)
  5. It can be reused with a similar purpose as it was in its previous use

With the above it can not be considered “Waste” I am sure there will be a lawyer out there with a different opinion.

If you choose to sell/move it to another location/give to a new owner it is a “2nd hand material” not waste.

All depending on your “state of mind” of course!

What happens next, (risk management)!

  • Council, Building Surveyor, Certifier, Engineer should ask is it “Fit for Purpose”?, is there a warranty? (regulatory/liability)
  • Can I get it in enough quantity? (buildability)
  • Owner/Community perception of quality? (reputation)
  • Will if perform as expected/understrength? (safety)
  • Resale/Valuation of building with repurposed material? (financial)
  • Poorly inspected/certified, moisture/mould/contaminants (health)
  • Insurance (all of the above)

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Passive Performance

We provide consultancy, advice, supply & install service for Passive House Construction & Air Barriers.

Do you need help with Passive House?

If you are a Designer who would like assistance with;

  • Ideas and concepts that will work
  • What details to provide
  • Planning the Air Barrier layer & or Blower Door Test
  • 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
  • Remove the fear of the unknown Blower Door Test (BDT)!
  • Achieve the ACH required!
  • Make the unseen or unknown visible with technology (pressure, smoke and infra-red cameras)
  • Reduce your risk & or do your installation, if preferred. We ensure the building is as airtight as possible before we finish the job
  • Work with you. Builders you can keep building, while we do the WRB and IAB!
  • Test early & test often, once the windows are installed, we test and then re-test after plumbers & electricians
  • Fix any damage to the air barrier system!
  • Provide Blower Door testing (ATTMA accredited). Depending on the project goals, we can do your BDT or work with your preferred tester!
  • Use the latest methods, tapes, sheets & liquids such as Proclima Intello, Adhero & Visconn.
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What is WUFI?

WUFI analysis is a method used to simulate the hygrothermal (heat and moisture) behavior of building components. Developed by the Fraunhofer Institute for Building Physics, WUFI stands for “Wärme Und Feuchte Instationär,” which is German for “Heat and Moisture Transient”.

Key Features of WUFI Analysis:

  • 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!

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Building Wraps, Class 4, Water Control, Condensation, Reflective, What the?

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
    • Air barrier – Air resistance of ≥0.1 MNs/m3
    • Non-air barrier – Air resistance of ≤0.1 MNs/m3

So what is this really all that about?  Condensation mainly and how to manage it, see our post on Condensation!

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.

Next thing to talk about is “direction of flow”?, please read more here!

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.
  • Occupant behavior

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Understanding Condensation!

Condensation is the process where water vapor becomes liquid. It is the reverse action of evaporation, where liquid water becomes a vapor.

Air contains some water vapour; warm moist air holds more vapour than cooler air.

Condensation occurs in one of two ways:

  1. The air is cooled to its dew point.
  2. The air becomes so saturated with water vapor that it cannot hold any more water.

The dew point is the temperature at which condensation occurs, Air temperatures can reach or fall below the dew point naturally, often at night which will make building elements cold either at or below dew point.

That’s why you see water droplets on the ground and around structures, and objects left outside in the morning.

You are likely to notice condensation on your window frames when you have a warm shower on a cold morning (cold aluminium at or lower than dew point temperature and warm moist air = condensation).

Condensation can also produce water droplets on the outside of a glass of cold water/beer. When warm air hits the cold surface, it reaches its dew point and condenses, leaving droplets of water on the glass.

Clouds are masses of water droplets in the atmosphere, as more water vapor collects in clouds, they can become saturated with water vapor.  As the density, or closeness of the molecules increase the clouds cannot hold any more water vapor. The vapor condenses and becomes rain.

Cold air holds less water vapor than warm air. This is why warm climates are often more humid than cold ones: Water vapor stays in the air instead of condensing into rain. Cold climates are more likely to have rain, because water vapor condenses more easily there.

When looking at the weather conditions you will see a term Relative Humidity expressed as a percentage of the maximum amount of water vapor the air could hold at that temperature, the higher number more vapour in the air.

More Building related, we are worried about what is called interstitial condensation which is the same process described above however occurs inside your walls or roof (usually hidden), this can lead to mould, mildew & decay hence can affect your health and the buildings structural adequacy.

Most issues with interstitial condensation are caused by us (humans) showering, breathing, cooking, washing & drying clothes inside a house.

As we increase building standards to produce buildings that are warm/cool (temperature difference from inside to outside) & airtight (no uncontrolled air movement, exfiltration/infiltration) we increase the risk of condensation occurring, so we need to be very aware of the materials we specify and how we construct buildings.  i.e. vapour open, vapour closed, what ventilation, what ACH or permeability we are expecting and if condensation does occur how does the building drain it out and how well/quickly the products dry out.

Contact us if you would like further information or help with a project.

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What is meant by Direction of Heat Flow?

Heat flow or Heat transfer, is the movement of thermal energy from a region of higher temperature to a region of lower temperature. This process continues until thermal equilibrium is reached, that is, until the temperatures in both regions become equal.

Put in simple terms heat flows from something that is hot to something that is cold (elements loose heat not gain cold).

There are three main ways heat flows:

  1. Conduction: This is the transfer of heat within a solid or between solids in direct contact. The heat flows from the hotter part to the cooler part. Examples would be direct fix cladding transferring solar radiation to the internal environment or a window exposed to the internal and external temperatures “conductive heat loss through the window frame”.

  2. Convection: This is the transfer of heat in fluids (liquids and gases) where the heated fluid rises and the cooler fluid sinks due to differences in density, setting up a circulation pattern known as a convection current. This regularly gets referred to as “stack ventilation” or “hot air rises”.

  3. Radiation: This is the transfer of heat in the form of electromagnetic waves, primarily infrared radiation. Unlike conduction and convection, radiation can occur in a vacuum, such as the heat from the Sun reaching Earth.  In building world we use a term thermal mass to describe the ability of a material to hold heat, e.g. solar action through the day will allow the thermal mass to gain heat and then as the air temperature drops at night it radiates the heat back to keep us warm.

It’s important to note that while we often talk about heat ‘flowing,’ it is actually the energy that is moving, not the material itself (except in the case of convection).

So if it is energy moving think about your power bill at home! We will use the words heat loss, this is another ways of saying wasting money.

In building world when describing where a control layer (insulation layer or air barrier) should be installed you will hear people say “on the warm side” this is talking about the direction of heat flow (hot to cold) and is dependant on your climate;

  • If we are talking about bulk insulation it is best located as close to the warm side of the building envelope.
  • If we are talking about an air barrier that restricts air movement, then we want it on the warm side of the building envelope.
  • If we are talking about a vapour barrier that inhibits moisture movement, we want it on the warm side.
  • If we are talking building materials and in a cold climate we want to keep things warm so they don’t reach dew point temperature, we want to reduce or avoid thermal bridging to avoid elements getting cold and reaching dew point temperature.
  • Hot humid climates, the warm side is usually on the outside, hence we are trying to stop heat getting in, trying to stop vapour from the outside, with air conditioning keeping the building cool, there is a high risk of interstitial condensation. Vapour or Air barriers on the outside of the building envelope will reduce the risk.
  • Cooler climates the warm side is usually on the inside, if it is somewhat airtight the vapour level will be higher on the inside, hence temperature or vapour is trying to get out of the building.  Showering and breathing will add moisture vapor to the air, there is a high risk of this vapour going through plasterboard and condensating within the walls. We want Vapour or Air barriers on the inside of the building envelope to stop the potential of this occurring.
  • Temperate climates can be in both directions, usually heating is more dominant hence both heat flow and the vapour drive will be from the inside to the outside similar to cooler climates.

Using the BCA to help the discussion, review BCA Volume 1 J4D4 Roof & Ceiling Construction

  • Climate zones 1 to 5 (middle to top of Australia) it says “downward heat flow” we are adding R value to stop downward heat flow or stop the heat getting in (heat gain).
  • Climate zone 6, (more the bottom of Australia) it says “downward heat flow” we are adding R value to stop downward heat flow or stop the heat getting in.
  • Climate zones 7 & 8 (Tasmania & Snow regions) ) it says “upward heat flow” we are adding R value to stop upward heat flow or stop the heat getting out (heat loss).

If you would like to know anything further, please contact us here!