Should top-up insulation cover loft air gaps?

Discussion in 'Builders' Talk' started by DG123, Oct 6, 2020.

  1. DG123

    DG123 New Member

    There are various air/ventilation holes in the eaves, which will be partially or wholly covered if the 200mm topper goes up to the edge. Am I to leave a gap to allow the loft to continue to breath?

    Thank you
     

    Attached Files:

  2. Jord86

    Jord86 Screwfix Select

    Yes.
     
  3. Frutbunn

    Frutbunn Active Member

    Yes as you have sarking felt rather than a breathable membrane.
     
  4. DG123

    DG123 New Member

    Thank you, yes certainly not breathable.

    I am planning for the 50mm air gap to be between this sarking and the Celotex, then insulated plasterboard over the celotex.

    Is this correct as I read elsewhere the air gap should be the warm side, I.e the celotex direct against the sarking??
     

    Attached Files:

  5. Frutbunn

    Frutbunn Active Member

    No you ventilate over the top of the insulation.
    Ventilation in your case is particularly important as you have Monarfol plastic sarking which will really cause your roof to sweat, fortunately it didn't last very long on the market.
     
    DG123 likes this.
  6. DG123

    DG123 New Member

    Good to know. Planning to add some felt lap vents in but i really don't feel any airflow beneath the plastic sarking when creating the gap. Still likely worth doing.
     
  7. John9857

    John9857 Member

    Hi, Make sure your loft has ventilation gaps at the eaves or is fitted with loft ventilation. Be sure to maintain this ventilation gap during and after installation
     

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