responsibility to retrofit existing structure during renovation

I am looking for some guidance and especially legal precedent for the responsibility and/or liability that an engineer may face when doing renovations and additions to existing structures.

In particular I am wondering how an engineer decides to what extent to require structural retrofitting of existing elements and systems that may be exposed during renovation under the following conditions:

1. the proposed renovations have little or no structural effect on the existing structural system.
2. the structural element/system in question has been exposed during renovation (eg. Removal of ceiling and wallboard).
3. the existing structure meets the code it was built under and is may not be considered immanently dangerous.
4. the existing structure clearly does not meet current code (eg. Trusses toe-nailed to top plate in high wind area).
5. the code exempts the existing structure from compliance with the current structural code because renovations are under a certain threshold.
6. minor structural modifications could greatly increase the safety of the building even if it doesn’t meet current code.

 

Thanks in advance.

 

Christopher Banbury, PE

President

 

Ark Engineering, Inc.

PO Box 10129, Brooksville, FL 34603

22 North Broad ST, Brooksville, FL 34601

Phone: (352) 754-2424

Fax: (352) 754-2412

www.arkengineering.net