What the calculations should establish
A useful package explains the building being assessed, the design assumptions, the loads and the route those loads take to the ground. It also addresses sideways stability: a building must resist more than downward weight. The City of London's submission guidance expressly asks for the load path, lateral stability and the basis of design to be explained. [2]
The figures should relate to identifiable elements on drawings. A calculation for a beam is not, by itself, a design for its connections, supporting masonry or foundations. Those interfaces need to be included in the design or clearly allocated to another competent designer. [3]
Calculations and drawings do different jobs
Calculations justify the design. Drawings and specifications tell the builder what is to be constructed and where. For domestic work, the engineer may assess the existing building, design new members and provide details alongside the architectural drawings. Check which of those outputs the appointment includes. [4]
Ask for a coordinated set, not a collection of unrelated beam printouts. A practical document check is to compare the project address, drawing revision, opening positions and member references across the package. Ask the team to resolve discrepancies before ordering materials; do not choose whichever version appears easiest to build.
When should they be prepared?
Bring the engineer into design development before structural assumptions become fixed. In some building-control processes, structural details can follow the initial submission, but their acceptance must be coordinated before the affected work proceeds. A condition requesting calculations is not a substitute for providing them. [2]
IStructE describes verification of existing structures as a process that addresses incomplete information through inspection, investigation and assessment. [5]
If opening-up reveals a different wall, support or existing beam, ask the engineer to review the design against that finding.
Which standards apply now?
Approved Document A is the government's published structural guidance for England. It describes ways to satisfy the requirements; it is not a catalogue of compulsory solutions for every site. The GOV.UK publication provides the edition incorporating the 2013 amendments. [6][1]
The Eurocodes are structural design standards, not legislation. BSI schedules withdrawal of the first-generation UK adoptions on 30 March 2028. During the transition, the engineer should identify the applicable generation and UK National Annexes; IStructE cautions against indiscriminate mixing of generations. [7][8]
Changes being reviewed
The Building Safety Regulator's call for evidence on Approved Document A closed on 21 April 2025. A call for evidence is not replacement guidance. Use the applicable published document and check the commencement of any replacement before treating a proposed structural requirement as current. [9]