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Suspended timber floor retrofit insulation (Q+A) G#3870

By 23 October 2015January 25th, 2017Code, Encyclopaedia, GBE Defects, Q&A

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Suspended timber floor retrofit insulation (Q+A)

Suspended timber floor retrofit insulation (Q+A)

Q I am currently trying to find a suitable insulation material that is:

Q1 natural-based;

  • Mineral/Animal/Plant: many
  • Mineral+Plant: Hemp-lime, Earth-Cork, Cob, 
  • Mineral: Cellular glass, Aerogel,
  • Animal: Sheep’s wool, Goat hair, Goose down,  
  • Plant: Wood fibre, Hemp, Cellulose fibre, Cork, etc.
  • not chemical, petrochemical, hydrocarbon, plastic

Q2 relatively great thermal insulator;

A2A  Conductivity?

  • (not plastic)
  • VIP Vacuum Insulated Panel,
  • Aerogel,

A2B Radiation?

  • Not plastic,
  • Not multifoils: (only reflective),
  • Cellular Glass,
  • Dense Wood Fibre
  • Cellulose fibre
  • Hemp-lime (improves as hydration progresses over long period)
  • Cork

Q3 airtight;

  • Foil faced (but not plastic) and taped joints None that I know about
  • Spray foam (but not plastic) None in market that I know about
  • VIP Vacuum Insulated Panel and taped joints
  • Cellular glass with taped joints or flood coat
  • Hemp-lime: Smoothing shown face will close surface
  • Cellulose fibre sprayed into place with or without added water

A3A Is it part of external envelop (includes suspended ground floor)

  • vapour open or vapour closed?

Q4 sprayable;

  • Cellulose fibre (Newspaper/magazine) flake, wet or dry application
  • Not Sprayed foaming plastic (but not plastic)
  • Plant based resin polyurethane (no longer made or sold in UK market)
  • Hemp-lime sprayed

Q5 adhesive enough to stick to horizontal surface (Should be Q1B) in this process)

  • Is this ground floor suspended or upper floor suspended?
  • Access for spray equipment?
  • Access to manual application?
  • Can the boards be lifted off, work carried out and boards relayed?

A5A (e.g. underside of floor boards on suspended timber floors). (Should be Q1A in this process)

  • Sprayed polyurethane (but not plastic)
  • Cellulose fibre (Newspaper/magazine) flake, wet application like papier mache
  • Hemp-lime sprayed

A5B Squeezy for compression between framing expansion and self-supporting between framing

  • Medium density cellulose fibre batts (poorer conductivity)
  • Medium density wood fibre batts (poorer conductivity)

A5C Supported by battens on sides of floor framing

  • High density wood fibre board (poorer conductivity)
  • High density cellulose fibre board (poorer conductivity)

A5D Supported by insulation support system stapled to sides of floor framing

I have been talking to Diasen (that manufacture’s Diathonite Evolution) and their product seems to meet almost all the above criteria, however, it is a bit too expensive.

  • Diasen
  • Diathonite Evolution G#1796 N#1683
  • You don’t get what you don’t pay for
  • Save some money somewhere else: taps, ironmongery, kitchen, bathroom, etc.
  • It’s the right price for a 4/5 multi-functional insulation
  • It may be the only product that is right for all 5 of your requirements
  • Anything less than 5/5 may be incompetent
  • Check with your client before choosing 4/5 or less at the wrong lower price

I wondered if you happen to know any other materials that meets these requirement (for example I came across with “ThermoPor”)

  • ThermoPor

Do you know how expensive they are compared to Diathonite?

  • No, that’s your job, ask the manufacturer.

Their lambda value is worse though.

  • You get what you pay for.

I am fully aware that both Diathonite and ThermoPor are originally for external wall cladding, whilst I am interested in floor insulation,

  • So is it competent in a floor situation?

but I am specifically looking for a sprayable adhesive material (due to access issues),

  • have you checked if the spray equipment can access your floor?
  • See my notes above interspersed with your 5 criteria
  • Is spray the only answer?

whilst I also try to stay away from Spray Polyurethane Foam SPF (to avoid off-gassing issues).

  • The plant based spray foam that was available was withdrawn because they could not be confident the resin was ethically sourced.
  • Find a SPF that does not off-gas?

© GBE NGS ASWS BrianSpecMan aka Brian Murphy
23rd October 2015 – 25th January 2017

Suspended timber floor retrofit insulation (Q+A)
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Ramshackle responses, some not very helpful.


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© GBE NGS ASWS BrianSpecMan aka Brian Murphy
23rd October 2015 – 25th January 2017

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