Thermal looping in cavity walls

The so called thermal looping effect in cavity walls is a common problem, wich lowers the insulation performance of the complete wall structure.


As a short explanation: cold air infiltrates the cavity in the winter from the outside and circulates inside of the cavity. As a direct result, the insulation performance is worse than calculated on the paper. 

KORE Insulation is explaining the thermal looping effect much better in one of their blog posts. The only thing, I can´t agree, is their suggested solution.


Coming from my experience, there´s is the same thermal looping effect in cavities, "fully filled" with insulation beads. I had plenty of buildings so far, where I noticed a draught coming out of the cavity through the reveals of the windows. The cavities have been filled with beads already and were blocked by using PIR board as cavity closers.

As soon as the gap between the window frame and the inner leaf is air tight sealed in an appropriate way, you blocked the access of the cold stream to the room. But she is still there and will circulate in the cavity further.


That´s why I would prefer the rigid cavity wall insulation, bonded to the inner leaf without any gap between the insulation board and the wall,  or - even better - to consider another wall structure instead of the cavity wall.



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Comments: 6
  • #1

    Mary McGillycuddy (Saturday, 10 March 2018 17:02)

    As often happens, for plumbing repairs or later renovations, once there is a break in the wall (e.g. for new pipes or vents) the insulation beads come pouring out and there is a little breeze remaining. This contributes to cooling.

  • #2

    prodomo Ireland (Saturday, 10 March 2018 19:09)

    It even happens without any subsequent void in the insulation layer. In comparison to a rigid insulation board, the structure of the bonded beads is more loose and allows a circulation of air trough it.

  • #3

    Ciaran (Tuesday, 03 April 2018 18:43)

    Hi I have an issue with damp in a bedroom with two exterior walls just wondering can you recommend anything? Also do you supply concrete bonding adhesive?

  • #4

    prodomo Ireland (Tuesday, 03 April 2018 19:05)

    Hello Ciaran, I can´t recommend anything without knowing the reason for your issue. I would highly recommend to get a survey done first, to find out what causes your dampness. I do not supply concrete bonding adhesive. Best Regards Philip

  • #5

    claire (Monday, 26 November 2018 22:20)

    HI, we have purchased a house with a cavity wall and one company told us to insulate external the house we should also fill the cavity to avoid any thermal loop, Is it true?

  • #6

    prodomo Ireland (Monday, 26 November 2018)

    Hi Claire,

    the company is right, the cavity should be filled to minimise the thermal looping and air circulation. It´s might worth to get an air tightness consultant/ tester involved, to detect potential air leakages before doing the insulation and for another test to monitor the performance, once the insulation is completed. Kind Regards Philip