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Solid External Wall Internal Thin Insulation (Q+A) G#11367

By 4 June 2016December 2nd, 2023Code, Encyclopaedia, Q&A

Solid External Wall Internal Thin Insulation Q+A

GBE > Encyclopaedia > Code > Q+A > G#11367

Aerogel and Board

Aerogel and Board

Questions & Answers:


Question

  • I noticed that you had latex thermal insulation on display on the table top.
  • What do you think of this product?
  • We have a client who has a very small house in a conservation area with small rooms and I am wondering if this is a “better than nothing” solution for them (they are strongly resisting losing any space whatsoever in the house).
  • Their other option is to do nothing about insulation (which they are favouring!!).
  • I know its not ideal, but as we said yesterday we don’t live in an ideal world.
  • Look forward to hearing your thoughts.

Answers:

Clarification: Latex

  • Natural Rubber Latex (NRL)
  • Used to make ‘Spitting Image’ Puppets
  • Variants used in ‘Memory foam’
  • Characteristics: Soft, compressible, cellular (still air enables conductivity thermal insulating properties)

Application:

  • Thin latex foam used as thermal conductivity insulation for internal application on solid masonry external walls
  • Promoted for use with wall paper as an ‘insulating wall paper’ sub-system
  • Availability: ≅ 5 and 10 mm sheets

Internal insulation of solid masonry external walls:

  • Since internal thermal insulation generates many problems that our industry does not seem to understand, I do not recommend it.
    • Normal practice is to batten out the internal surface and insulate with rigid insulating boards not in contact with the wall
    • This can lead to condensation:
      • leading to mould, ill health, asthma, toxic mould, death, unusable building
      • rot, structural failure of embedded timbers, frost damage to outer face of masonry
  • Conventional insulation materials are mostly wrong for this application including: mineral wool and foamed plastics
    • Mineral wools:
      • because they are normally hydrophobic and will hold moisture vapour in the interstices preventing trapped air from doing the job of insulating and reduce the materials performance
    • Foamed plastics:
      • because they will not permit the wall to breathe

        aider à réduire la masse grasse tout en augmentant la masse musculaire et la force 3, cependant, en raison de sa puissance, il faudra un soutien pendant et après le cycle. anastrover de maigreur dur et sec, bien que si la tendance hybride se poursuit, ces deux peuvent faire face à un défi cette année à venir.the wall to breath moisture vapour outwards

Latex internal insulation of solid masonry external walls:

  • I will only recommend latex use to the poorest who cannot afford to heat their building fabric, and can only afford to heat the space.
    • Because latex is sold as a thin solution it has a relatively low improvement in stopping heat flow through the wall.
    • Keeping it thin helps to reduce the risk of frost damage to bricks becoming too wet and too cold.
    • However there is an alternative material on the market that can do a similar job.

Alternative materials:

  • An alternative material for very thin insulation for application internally on solid masonry insulation is aerogel
  • These are supplied as a quilt in multiples of 5 mm thickness
  • They are also supplied bonded to lining boards

Further investigation needed:

  • I do not yet understand latex’s moisture permeability or moisture transport characteristics
  • Is it open or closed cell?
  • If latex is vapour open
    • it may allow moisture flow inwards which will allow evaporation inwards when conditions demand and permit.
    • If gypsum or cement plastered walls:
      • remove plaster to permit the wall to breath inwards
      • loss of plaster and gain of insulation will not alter their room size too much.
    • If lime or clay plaster
      • wall will breath without modification
  • If latex is vapour closed
    • then I would be a bit more worried about it.

Soft insulation used with wall paper:

  • A soft material behind wall paper, is how it was promoted to me, is prone to damage
  • Consequences of this approach:
    • Rehanging skirtings, dados, plate shelves, picture rails, selves and wall units is complicated with soft insulation and wall paper.
      • They will need softwood shims the same thickness as the insulation to space off the wall and not compress the insulation
  • Be careful if you choose PVC vinyl wall paper for toughness then you close the wall to moisture permeability in either direction.

If you do not insulate:

  • If you do not insulate then they need to consider green tariff energy supply and/or renewables with pumps, controls, motors, monitors, driven by green tariff electricity.

Heating the spaces:

  • If you were to use radiant heating, it heats the objects in the room, not the air and so warm air is not against cold walls.
  • Floor, ceiling or internal partition mounted radiant or convector heating ‘radiators’
  • Avoid radiators on External wall,
  • Use just below surface hot pipes or electric films.
  • Or hidden pipes in skirting radiators

Other measures:

  • Add reflector panels behind existing and new radiators.
  • Maximise draught stripping to windows and doors
  • You may know this already
  • I hope this is of some help.

© GBE GBC GRC GBL NGS ASWS Brian Murphy aka BrianSpecMan ****
6th December 2012 – 2nd December 2023

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