“Structural dampness is the presence of unwanted moisture in the structure of a building, either the result of intrusion from outside or condensation from within the structure.” ref. Wikipedia

gutter with weeds and faulty downpipe

Weeds growing out of gutters and defective pointing

As the title suggests, Penetrating Damp is the result of moisture penetrating the structure of the building. This is often the result of:

  • Broken or missing slates/tiles
  • Faulty brickwork and pointing around the chimney breast
  • Faulty leadwork – flashings, skews
  • Mortar joints between the brickwork
  • Gutters and downpipes that are missing, broken, cracked, have leaking joints or connections
  • Raised ground level
  • Weeds and vegetation that may be blocking the gutters, growing out of cracks in the pointing, or growing too close or on a building e.g. Ivy
  • Joints around windows and doors – rotten timbers, defective sealant


  • Assess and repair external faults (see above)
  • Repair/treat the effects of the external faults after a proper assessment has been made. Contact McKnight Building Preservation if you are experiencing any of these issues



Damp wall with peeling wallpaper caused by condensation

This is not considered a ‘penetrating damp’ issue, but more an issue with water vapour that is produced inside the building by internal, usually ‘lifestyle’ means.

  • Poor ventilation
  • Drying clothes indoors
  • Shower/bathing
  • Cooking
  • Inadequate wall, ceiling and floor insulation
  • Lack of heating

Examples of Penetrating Damp work that we have carried out.

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