Viewing 5 posts - 1 through 5 (of 5 total)
  • Author
    Posts
  • #31552
    Tim Barrett
    Member

    I would like advice on the best type of plaster to use to give the best thermal conductivity. The walls are highly insulated with 100mm solid concrete blocks internally to give thermal mass so I don't want the plaster to insulate it in any way.

    #38086
    Anonymous
    Inactive

    I would like advice on the best type of plaster to use to give the best thermal conductivity. The walls are highly insulated with 100mm solid concrete blocks internally to give thermal mass so I don't want the plaster to insulate it in any way.

    Interesting question! I hope somebody knows the correct answer but in case they don't, here's some speculation:
    (1) keep the layer of plaster as thin as practicable

    (2) according to http://www.jupiterunderfloorheating.com/uploads/knowledgeBase/W1.PDF “Cement plaster e.g. Marmorit Rotkalk” has better conductivity than clay or gypsum plaster.

    (3) you could try mixing in some components with higher thermal conductivity, such as carbon fibres.

    But I think the first thing to do would be to model the effect of the layer of plaster to see what it effect it has and how much effort or money its worth spending on optimising it.

    #38087
    Daren Thomas
    Participant

    Why not render the walls and finish with a skim of plaster. This will give a thickness of 12mm and max 5mm.

    #38088
    Mark Siddall
    Participant

    Dense blockwork has a conductivity in the range 1.1 to 1.2 W/(mK).
    13mm Dense gypsum (1300 kg/m3) has a conductivity of 0.57 W/(mk).
    13mm Densure gypsum (1000 kg/m3) has a conductivity of 0.4 W/(mk).
    Render, cement/sand, has a conductivity of about 1.0W/(mK).
    Render, gypsum/sand, has a conductivity of about 0.8W/(mK).

    Consider render with thin, 3mm, gypsum finish?? (a bit experimental as may crack due to differential propoerties.)

    Though if you think about the wall as a whole the insulation is likely have a conductivity of 10x greater than that of insulation.

    M

    #38089
    Tim Barrett
    Member

    Thank you for that Mark and I'm sure you're right, it's hardly going to make any difference any way. I quite fancy using lime render and set for it's other properties, any thoughts?

    Tim

Viewing 5 posts - 1 through 5 (of 5 total)
  • You must be logged in to reply to this topic.