Zinc Roofing

 

Zinc is sometimes used as a roofing material.  Cheaper than other metal roof coverings (such as Lead or Copper) it more limited as it is harder to work with.  It does not adhere well to other materials, is very corrosive in anything other than PH neutral conditions.

Nevertheless Zinc is encountered during surveys relatively frequently.  

Surveyors have noted that waterproof under lay or under felting is often absent from Zinc roofing installations meaning leaks and damp can result.

It is often hard to see (visibly) if the zinc is pierced or cracked without close inspection.  This would require getting on to the roof.

Sometimes the Zinc sheet is terminated in a mortar joint ( e.g. on a parapet roof).  This can result in an acidic condition leading to corrosion.  The section of zinc that is embedded in the mortar should be sealed to prevent this.