Checklist For Inspecting Cast Iron Failures

Procedure code:
Outdoor Sculpture Manual - Center For Public Buildings
Metal Materials
Last Modified:



Margot Gayle, David W. Look, John G. Waite. Metals in America's Historic Buildings. Washington: National Park Service, 1992


L. William Zahner. Architectural Metals: A Guide to Selection, Specification, and Performance. New York City: John Wiley & Sons, 1995.


National Park Service: Preservation Brief 27,  The Maintenance and Repair of Architectural Cast Iron 


This general checklist is an aid for inspecting the condition of
cast iron.  It should be used as a supplement to 05010-04-S "Cast
Iron:  Characteristics, Uses and Problems".

1.   Examine the overall surface condition and appearance, paying
    particular attention to horizontal surfaces.  Look for cracks,
    crevices, pockets, folds or details in the metal which may
    collect and hold water.

2.   Examine and evaluate the coatings; determine the type and age
    of protective coating by visual or laboratory analysis.  Look

    a.   Cracks or breaks in the coating such as crazing, hairline
         cracks, cracks along seams, or other fractures in the
         surface, evidence of rust or rust stains at crazing, or
         blistering/flaking adjacent to cracks.  Failures of this
         type may be one of the earliest warning signs of
         potential deterioration.

    b.   Bubbles or blisters on the surface of the coating.  This
         type of failure results from the separation of the
         protective coating from the substrate.  When left
         unrepaired, these air pockets may trap water or moisture
         and may accelerate deterioration or produce corrosion.
         Waxes and oil coatings are not susceptible to blistering.

         1)   Note extent of blistering and location of problem.

         2)   Is the problem localized or general?

    c.   Peeling and flaking of the surface.  This usually results
         from unrepaired cracking or blistering (discussed above)
         and represents a more advanced stage of coatings failure.
         Areas left unprotected due to coatings loss may result in
         rust or corrosion.

         1)   Note extent of peeling/flaking and location of

         2)   Is the problem localized or general?

    d.   Erosion and wear of the surface.  Carefully examine the
         coating as well as the bare metal.  

         1)   If possible, note all evidence of wear due to
              environmental or natural exposure.

         2)   If possible, note all evidence of wear due to human
              exposure or vandalism.

    e.   Graffiti on the surface.

         1)   Note basic types of graffiti material used such as
              paint, greasepaint, lipstick, marker, etc.

         2)   Note pattern of graffiti and location.

    f.   Structural and mechanical deterioration.  Look for
         rusting, cracks, breaks, etc.  Monitor areas of concern
         to determine if they are active.

         1)   Identify locations of broken pieces.  Note if they
              are missing or salvageable.  Label all recovered
              material to location.

         2)   Identify locations of breaks at seams.  Note
              whether connectors are missing or loose.

                         END OF SECTION

Last Reviewed 2013-08-20