Outline of an Expansion Joint


Flashing is a thin piece of impervious (doesn’t allow fluid to pass through it) material which is installed to prevent moisture penetration  into a building or structure.


There are many materials used for flashing each with their own benefits and drawbacks depending on their application. Such materials include:

  • Lead
  • Colorbond
  • Alcore
  • Zinc Alloys
  • Copper
  • Anodised aluminium
  • Polythene


The purpose of flashing is to avoid moisture penetration into a structure. Flashing will be utilised in a number of areas around a structure, common areas include:

  • Apron flashing
  • Hip flashing
  • Sill flashing
  • Valley flashing
  • Through/In wall flashing

Flashing Defects

Some of the more common defects during a building and pest inspection, relating to flashings include:

  • Common among older metal based flashings is corrosion and holing to the flashing.
  • Inadequately installed flashing.
  • We often find lead based flashings which have been cracked.
Rusted and inadequately Installed apron flashing.
Deteriorated and cracked lead apron flashing.
Rusted valley gutter flashing.