What determines the scope?
A load-bearing wall with clear supports differs from an opening that also needs columns and foundation changes. For extensions, roof build-up, ground conditions and the connection to the house also matter. Describe these in your enquiry so they do not emerge only after the quotation.
Which costs are separate from calculations?
Ground investigations, archive research, building surveys, architectural drawings and application fees are not automatically included. Neither are steel supply and installation. Ask for a specific scope. Calculating an element and constructing it are different tasks.
Use the calculator for initial guidance
The calculator on this website shows a starting price for your project type and highlights possible additional work. It does not calculate beam sizes, foundations or permit requirements. Combined projects need an individual quotation because simply adding starting prices can be misleading.
Practical checklist
- Check what is included
- Identify combined alterations
- Explain which documents are missing
- Request a final quotation
An investigation cost estimate without a defined investigation question is unreliable.
Preparing your own project
Would you like this assessed for your home? See our information about other structural calculations. It explains which information is relevant to that brief. The project check helps you prepare your enquiry.
Unsure about a term? The structural glossary provides plain-language explanations and technical context. To understand how the documents are organised, explore our fictional example project .
Editorial guidance • updated 2 October 2026. General information, not a project-specific assessment.