Removing Cavity Wall Insulation (Q+A) G#38597

By July 10, 2020Code, Encyclopaedia, Q&A

Removing Cavity Wall Insulation Q+A

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Removing Cavity Wall Insulation Q+A
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Q         Reusing cavity wall insulation extracted from cavity walls

  • We are also extracting cavity wall insulation (and refilling with EPS bead) – a recent chat with another installer left us thinking about the extracted material (typically it’s what the industry calls foam insulation) and how it can be re-used for loose fill loft insulation.
  • There is potential for extracting this insulation and re-using it to insulate the loft at the same property.

A          Reusing cavity wall insulation extracted from cavity walls

  • Question: What materials is being extracted, Answer: Foam insulation
    • Does it contain ozone depleting chemicals as foaming agent gases
      • Is it a hazardous waste that needs to be captured along with all the released gases?
      • How much ODP gas has already been released?
    • GBE anticipated a second wave of Ozone Depletion Potential due to pre and post 1980’s ODP use in thermal insulation until their use was outlawed in EU.
      • Specifiers and developers preoccupied with thin construction persisted in specifying ODP gases up to the last minute.
      • Demolition of these buildings will release ODP gases
      • Extracting their insulation will release ODP gases
    • Question: Why is it being extracted?
      • Is its ODP safer where it is?
    • Is it causing damp penetration?
      • This may be due to patchy, inconsistent or intermittent installation
    • Is it Urea Formaldehyde based?
      • This was seen as a health problem due to off-gassing
      • After a long time installed is that still an issue? I do not know.
    • Wanted to improve the performance of the cavity wall insulation
      • Whey then replace it with MOR Middle of the Road performance EPS Expanded Polystyrene
      • It is after all another Foam insulation material, but in bead format
      • Bead format leaves interstices between the beads,
        • a route for free flowing air with heat and moisture
        • a space for eddy currents to establish themselves
      • Can the density of the installation be increased to squeeze, flatten and close the interstices?
      • If you squeeze them this much is the insulation performance of the bead diminished?
    • Question: How easy is it to comprehensively remove a set injected foam insulation
      • Vacuum is not enough
      • There has to be an element of mechanical disintegration
        • Releasing ODP?
      • From every nook and cranny (jargon for all the remote corners)
      • All the materials fortuitously attached, by mechanical key to textured surface or bonded to the surfaces of the cavity
      • What level of inspection is applied, that the work has been done well enough/at all?
    • Question: Is the extract arising’s a waste or a resource?
      • Extracted materials would be classed as a waste
      • Does it contain ozone depleting chemicals as foaming agent gases
        • Is it a hazardous waste that needs to be captured along with all the gases?
      • Handling it may require a special license
      • Moving it from the site may require a special license
        • A hazardous waste license?
        • An ODP waste license?
      • Keeping it on site and reusing it may not need a special license
        • Fortuitous Serendipitous idea if it’s a good one
        • Using the material is one thing
          • Are you happy using a hazardous material (read Deleterious) in a building occupied by humans?
        • But the ODP gasses remain a major problem
      • Question: Do you have to provide any form of guarantee/certificate for the attic insulation?
        • Reclaimed materials could be available with a Product Passport
          • Your supply chain would need to establish the process
          • It should identify the materials and its properties
            • It was considered inadequate for exiting cavity
          • Confirm it is uncontaminated
            • Needs clean storage vessels
            • May need ODP capture and special disposal
          • Confirm it is in good condition
            • But you just smashed it up to get it out
          • Recycled materials will not be available with certification for installation
            • The original manufacturer
              • is unlikely to provide a warranty for its smashed up material
              • will not be able to confirm its k value now that the ODP has been lost
            • Question: is this work being done under an Energy Performance Contract (EPC)?
              • Will the disintegrated foam insulation be effective as an insulation?
              • Will a plastic foam minus its ODP gases have a useful k value?
              • Will it compact down to close the air pathways through the interstices between the fragments?
              • Is avoiding overheating a criteria for EPC success?
              • Plastic insulation will not provide decrement delay to protect from solar radiant heat gains through the opaque roof coverings

© GBE GBC GBL NGS ASWS Brian Murphy aka BrianSpecMan **
10th July 2020

Removing Cavity Wall Insulation Q+A
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© GBE GBC GBL NGS ASWS Brian Murphy aka BrianSpecMan **
10th July 2020

Removing Cavity Wall Insulation Q+A, G#38597

GBE Question & Answer (Template) Q#14864

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