GeoInsighter Winter 1999 Newsletter

Limit Your Liability Using Pre-Construction Surveys

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Are you considering new development, additions, or renovations to property? If you are, then you may want to consider implementing pre-construction and post-construction surveys. The purpose of these surveys is to establish conditions existing prior to and following work you perform when such work may cause disturbance to nearby existing properties. Establishing conditions can be a significant step toward avoiding false damage claims by property owners who might otherwise assert that the construction you performed caused damage to their property.

Example sources of potential damage include the following; 

• blasting vibrations;

• vibrations associated with demolition or excavation;

• heavy truck traffic;

• settlement caused by dewatering operations; or

• lateral ground movements associated with excavations. 

Existing conditions are typically established and recorded by evaluating the nature of the proposed construction and the extent of its potential impact, identifying potential receptors, and then developing a cost effective survey program. For each property identified as a potential receptor, the survey includes documentation of existing conditions by usually using a combination of the following methods:

• vertical elevation survey to establish elevations of benchmarks created specifically for the survey to monitor potential settlements

• Research of utility records associated with nearby utilities to identify past problems;

• measurement and photographic documentation of existing property damage (i.e., cracks in walls and floors, evidence of water damage, tilting retaining walls, broken windows, clogged subsurface drains, heaved or cracked pavement surfaces, etc.);

• detailed notes regarding the character of the subject properties;

• installation of tell-tales (temporary surface-mounted devices or measurement reference points that allow the precise measurement of crack widths or locations); and

• installation and data collection from more sophisticated measurement devices (i.e., automated electronic fixtures).

The timing of the pre-construction survey is typically coordinated as close as practicable to the proposed work to establish existing conditions. Depending upon the nature of the surroundings (i.e., commercial, residential, etc.) significant preliminary work may be required to obtain access agreements and schedule visits to the properties. The scope of the survey must be detailed and extensive enough to take into account the nature of possible damages, including:

• inconvenience to abutters (i.e., vibration only);

• cracked plaster or glass;

• hairline cracking in foundation walls;

• settlement and related damage (i.e., jammed doorways and windows)

• new leaks of ground water into below ground areas; and/or

• significant structural damage (i.e., broken utilities, titled foundation walls). 

Monitoring during the construction allows an evaluation to be made regarding whether modifications of construction activities are warranted. Post-construction surveys should be performed as soon as practicable following the work to document changes, if any, to conditions recorded prior to the work. The survey measurements are ideally performed by the same person or team to keep observations consistent. It is generally helpful to submit a copy of the pre-construction survey of existing conditions to the identified abutters (and third parties, if necessary) to create a paper trail and establish the limits of your liability. Similarly, a copy of the post-construction survey is also forwarded to the abutters to document that (hopefully) no damaged was caused. The intent of the latter submittal is to close the door on liability for future claims.

As with most preventative exercises, a balanced must be reached between the actual risks of damage posed to the abutters against the scope and cost of the survey. However, in today's liability conscious world, preventing potential false claims is worth your careful consideration.

Michael C. Penney, P.E.
mcpenney@geoinc.com

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