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Should we insulate the entire roof?

Hello, and thank you for your show that I am every Saturday. I want to isolate my attic on my house that has just been isolated from the outside (facades and gables). My roof has an HPV film. I wonder, knowing that in these attics, the upper part (above a false ceiling) will not be fitted, if I have to isolate the entire roof or if I have to stop this insulation at the level of false ceiling (insulating the false ceiling, of course). If I stop the insulation in the middle of the roof, the interior of the gables will be cold in winter where a super thermal bridge, and the ITE is no longer useful. If I isolate the entire roof, what about the enclosed space between the false ceiling and the ridge, especially in terms of condensation? A VMC suction mouth (with air inlet from the house) and / or a vario film can solve this potential problem. thank you in advance

It is always better to insulate the sub-roof sections on their entirety. But you can also, as you suggest, isolate only the part that will be arranged, isolating the "floor" of the part of your attics lost since they will not be arranged.
Several solutions are available to you depending on the nature of the "ceiling", I invite you to consult our fact sheets where their implementation is described:

  • the insulation of the attics lost, which concerns the blown insulators.
  • the floor insulation of the attic, which details the installation of a roll insulation.

On the same topic

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    • Insulation of lost attics (blown wool)

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