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Refurbishment and change of use: Flowchart of the design assessment process
A flowchart showing the typical staged structural assessment process for refurbishment and change of use of existing buildings.
Ohr Notes
Ohr Notes 006 · June 2019 · Rev 00 July 2021
The design assessment of an existing building, either for change of use or refurbishment, is often not a straightforward linear process and has to be undertaken in stages. This flowchart outlines the typical steps to give a general understanding of this process. Refer to an engineer for the specific requirements for a built.
01 / Establish available information
Are engineering drawings and design information available?
Undertake desktop design assessment
Depending on the information available, determine the theoretical capacity of the existing structure and its capacity to accommodate the proposed use or refurbishment.
Engineer’s deliverable: report outlining the assessment undertaken and findings.
Undertake structural layout and dimensional survey
A building surveyor undertakes the survey. It may not be possible to determine slab thickness through this survey.
Surveyor’s deliverable: structural layout drawings with structural elements dimensioned.
Undertake a basic desktop structural review
Review the layout drawings to understand the potential implications of the proposed use or modification.
Engineer’s deliverable: report outlining observations made.
02 / Visual condition survey
Undertake a non-intrusive survey of the structural components that are visible and accessible at the time of the survey. Determine their general condition, identify any visible defects and deterioration, and assist in determining any further needed structural investigation.
Engineer’s deliverable: report outlining observations made.
03 / Determine further structural investigation
Use the findings of the desktop assessment and visual inspection to determine the structural investigation required. A comprehensive investigation is required if the engineering drawings and design information are not available.
Engineer’s deliverable: scope of works and specification for the investigation proposed.
Detailed investigation and testing
The specialist contractor undertakes the investigation with the oversight of the engineer.
Contractor’s deliverable: report outlining the investigation done and the findings.
04 / Review or update desktop design assessment
Review and update the earlier desktop design assessment using the findings.
Engineer’s deliverable: updated assessment report.
05 / Determine structural interventions
Is structural strengthening or a new load-independent structure required?
Design assessment complete
Is a new foundation required?
No — Undertake design.
Yes — Undertake soil investigation, then undertake design.
Design assessment complete
First published: June 2019
Revision 00: July 2021