Ceiling mould/mildew growth adjacent to the external walls

Causes

Condensation forms on the ceiling because the roof space insulation has not been taken to the eaves 

Listed under: Interior, insulation, health and safety, ceilings, roof space, moisture, condensation, mould, mould health and safety

Cause

Condensation forms on the ceiling because the roof space insulation has not been taken to the eaves 

Repair

  • install insulation as close to the edge of the roofspace as possible, covering the whole ceiling area (but not the top plate)

  • where the roof space is fully accessible, fit bulk insulation between and over ceiling joists, with no gaps or folds

  • where the roof space is only partly accessible and segment or blanket-type insulation cannot be fitted by hand, consult an experienced specialist contractor to install blown-in, loose-fill insulation

  • to remove mould/mildew, wash the ceiling with a fungicidal wash to kill the mould. Repaint with a quality paint that includes a fungicide

  • reducing moisture levels in the house will also help to reduce condensation:

    • avoid the use of unflued gas heaters inside

    • avoid drying clothes inside

    • install a rangehood over the cooktop and vent the cooking steam outside

    • install an exhaust vent near the shower in the bathroom and vent the steam outside; or install a shower dome above the shower

    • opening windows wide for at least 10 minutes every day can make a difference

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