Insufficient Structure
Insufficient structure – IS- is a general term that might be appropriate if there is evidence of obvious shortcomings such as too long a span and failure to properly support floors above or there are cracks which need further analysis. Notation may be made if structural members, such as joists and beams, seem too far apart or they span too long a distance, or that the size of the member is too small to carry the load. Also, the cutting or notching of elements can reduce their bearing capacity. Bouncy floors are one way of testing that there is insufficient structure to meet loading criteria. Also support posts and studs set too far apart or too small in section may seem to have weak lateral support when pushed .The use or crack monitors is helpful to indicate if insufficient structural conditions are stable or not. In surveying a property, it may be sufficient to make a notation of IS for insufficient structure or to use the following notation and reference to each entry; Missing Structure -MS, or Undersized Members for code compliance -UM