The following is an excerpt from a Concrete Expert Witness report of an estate residence where stone work had been damaged by high-pressure washing over the course of time.  Through the investigation and examination process recommendations were offered for repairs. 

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Executive Summary:

An investigation into the consequences of high pressure washing activities for the 

removal of smoke damage to exterior property was conducted.  Virtually all of the

estate sized view-lot property improvements feature stone in the paving, steps,

stairways, columns, planters, pilasters, patios, walks and window and door sur-

rounds.  Many of the horizontal and vertical stone surfaces examined presented

contrasting areas within their fields strongly representative of localize distress as

would result from a lingering high velocity, high-pressure water spray. Other of the

surfaces, particularly at edges and corners displayed contours, shapes, and

patterns that would be associated with high spraying pressures.  In many cases,

it was obvious that during or before the installation of the stone improvements sur-

face blemishes were present and had been repaired by epoxy filling, a common

practice.  It was evident at many locations that these epoxy repairs had either been

completely dislodged or otherwise affected by the high-pressure washing.  In

addition to distress cased by high-pressure washing, collateral damage to other improvements and personal property was verified that the homeowner indicated was due to the cleaning contractor.  Some stone distress was present that appeared completely unrelated to cleaning activities.  Not distress was noted to exterior plaster surfaces. 

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The site includes an extensive variety and quantity of diverse dimensional stone and cut stone finishes.  While an exhaustive examination was not conducted, the amount of stone work carefully examined may constitute a representative sample of the condition of the stone work at the property.  The examinations made largely include consideration of surface sheen, textures, and profiles, and actual and incipient epoxy filling the bonding.  And, of these indications some of the most significant were made on arris sections like corners and cut or carved linear reveals, compound edges, or design elements in the stone faces.

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Examination of the stone surfaces generally shows that dependent upon the area represented, high-pressure cleaning activities have partially, greatly, or completely removed the original chemical sealer, which was probably applied to all surfaces.  Likewise, the delicate arris and carved design sections show a wide range of textures ranging from normal wear and tear and normal variations of manufacturing and installation to fairly deep surface profiles indicative of high-pressure water cleaning. 

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There is no question that there are many areas in virtually all of the various elements and stone surfaces that aggressive cleaning has occurred.  On the other hand, there was evidence of the original sealer remaining, accompanied by observation of normal surface profiles and typical wear and tear.  The process of itemizing and listing each of these polar observations in a detailed and comprehensive manner is enormous, and more difficult still is to identify the areas with conditions in between.

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The areas of excessive surficial distress identified herein constitute evidence of the pressure washing contractor violating its standard of care and potentially being negligent in so doing.  If, as was explained (and the undersigned has no reason to doubt it) various items (generally stonework tops and planter pots) at the site were outright broken or damaged, then this would constitute additional evidence of a violation of its standard of care as well as negligence.

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It is expected that most of the distressed surfaces can be restored by qualified craftsmen.  Some localized repairs that are more significant will be required.  Some items require replacement.  It is not possible at this time to prepare any sort of inventory or costs estimate for the repairs, and some detailed, suitable, and fair standard for needed remediation should be established prior to contracting for them.