What Can We Tell from This Photo? (Case Study 4)

Posted by in Basements, Cracking, Masonry, Simple Forensic Methods | October 20, 2014


This is an exercise to develop the abilities of observation.

What can one know from examining this photograph?

The pattern of the joints under the coating indicate that this is a concrete block wall.

The coating appears to be a thin cement based coating usually applied for interior damp proofing, such as a home made mortar or Thoroseal.

The sharp-edges and relatively clean fracture surfaces indicate that the cracking and chipping of the coating occurred relatively recently.

However, the rounded edges on the cracking under the coating indicate that the cracking in the original wall has been present and exposed for years.

The moisture staining at the joints indicates that there has been water inside the hollow cores of the block. The source of the water may be infiltration through the block or the wall above, but is most likely ground water.  Further examination of the construction around this wall is necessary to determine the source.

The lack of any remnants of a mortar like patching material over the rounded cracking indicates that the cracking was not repaired or patched by re-pointing the mortar in the joint, but that the thin coating merely bridged over the original cracking.  A thin bridge coating is very weak and in time the original cracking will almost always extend through the coating.

The diamond shape of the chipping in the coating indicates that the chipping probably occurred during a cyclical movement, that is, a back and forth motion and even a slight up and down motion.

Do you have any other observations that we missed?

Please write to us at engineering@prugarinc.com and let us know.