When insulating a loft at ceiling level with mineral wool type material, should the insulation cover the exposed wall cavities for external walls?

1 Answer 1


Your insulation should cover the top plate of the wall. This gives you a complete thermal envelope. Covering the wall cavities will help keep cold air from coming up to the upper areas.

  • I agree, but insulation isn't intended to block airflow. (You probably meant heat transfer via conduction.)
    – isherwood
    Feb 12, 2019 at 15:43

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