Municipal review
Municipalities often request structural substantiation for permit-triggering works or when drawings indicate relevant structural intervention.
- Permit review package
- Structural logic explained
- Consistent with drawings
Structural calculations for renovation and building works
Structural Calculations and Engineering Advice for Renovation, Alterations and Building Works
Planning a renovation, extension, wall opening or roof intervention? Then structural calculations are often the technical foundation of the entire project. Aboss provides structural advice, engineering calculations and technical substantiation for permit applications and execution.
Whether the project involves removing a load-bearing wall, creating a floor opening, designing a steel portal frame for an extension, or assessing a roof extension on an existing building, the structural logic has to be clear before the municipality, contractor or insurer can move with confidence.
- Structural calculations for renovation, extensions, roof extensions and floor openings
- Permit-ready substantiation aligned with execution reality
- Clear coordination between architecture, structure and technical feasibility
When structural calculations are needed
When are structural calculations required in renovation or alteration projects?
Structural calculations are required whenever an intervention affects the load-bearing system of a building. This is not limited to large extensions. Many common works in existing buildings already have structural consequences, such as removing a load-bearing wall, cutting a stair opening, adding steel beams, increasing floor loads or modifying the roof structure.
Execution risk
Without calculations, contractors can run into uncertainty on site, especially when the real building deviates from old drawings.
- Safer sequencing
- Better decision-making
- Less improvisation on site
Liability and insurability
Structural substantiation is also relevant for responsibility allocation, insurer confidence and demonstrating technical care.
- Documented assumptions
- Visible engineering rationale
- Improved project defensibility
Extension, rear extension and roof extension
Structural calculations for extensions, rear additions and roof interventions
With an extension, rear addition or roof extension, the structural system of the existing building almost always needs to be reassessed. Load paths, deflection, bearing conditions, stability, foundation response and interaction with the existing house all matter.
Typical calculations
- Structural calculation for an extension or rear addition
- Foundation assessment for added loads
- Steel structure for façade openings
- Roof extension support on existing buildings
Why it matters
- The intervention may look simple architecturally but can be demanding structurally
- The existing building often controls the feasibility of the solution
- The permit file and the execution package should speak the same technical language
Load-bearing walls and wall openings
Structural calculations for removing a load-bearing wall or creating a wall opening
Removing a load-bearing wall without structural design is one of the classic risks in residential renovation. What seems like a limited architectural intervention can be highly relevant structurally. The engineer has to determine how loads are redistributed, what beam or frame is required, how bearing works and whether temporary shoring is needed during execution.
Typical deliverables
- Beam and frame calculations
- Bearing checks and support details
- Temporary shoring advice where relevant
- Substantiation for permit and execution
Typical situations
- Kitchen-living room opening
- Rear façade opening for an extension
- Wider passage between rooms
- Alterations in masonry load-bearing walls
Existing buildings and renovation logic
Engineering advice for existing buildings and renovation projects
Existing buildings require a different approach than new build. Renovation projects involve old construction methods, partial documentation, ageing materials, hidden details and frequent differences between drawings and reality. Good structural advice is therefore not just about calculation, but also about assessment and interpretation.
Assessment of the current structure
We look at the likely load-bearing logic of the existing building and how the proposed intervention interacts with it.
Risk awareness
We consider cracking, settlement, hidden weak points and whether additional inspection or measurement is advisable.
Technical feasibility
The objective is not to produce a generic report, but a technically workable solution that fits the real project.
Foundation, steel and shoring
Foundation checks, steel structures and shoring plans
Many alterations require more than one isolated calculation. Larger openings, expansions or structural repairs often involve a combination of foundation response, steel elements and temporary support measures.
Foundation and load increase
- Additional load from extensions
- Foundation suitability review
- Settlement-sensitive situations
Steel beams, columns and portal frames
- Beam calculations
- Column and portal frame design
- Connection logic and support conditions
Shoring and temporary support
- Relevant when loads must be temporarily carried during demolition or opening works
- Supports safer sequencing and execution planning
- Reduces avoidable on-site risk
Permit and execution alignment
Structural calculations for permits and for actual execution
Municipalities regularly request structural substantiation for permit applications, but even where a permit is not always explicit, the structural report still often forms the backbone of a safe and coherent project. A good file contains not just formulas, but a readable structural narrative that aligns with the drawings and the intended works.
Review of the intervention
We identify the structurally relevant works and the likely information gap between the idea and the real building.
Calculation and technical substantiation
The calculation package sets out loads, assumptions, chosen elements and the structural logic of the proposed solution.
Coordination with drawings and permit path
Where needed, the engineering is aligned with architectural drawings and the permit package so the file remains coherent in review and execution.
Why Aboss
Why choose Aboss for structural calculations?
Aboss works at the intersection of architecture, structure and permit logic. That means the project is not viewed as isolated calculation work, but as a technical trajectory in which feasibility, review-readiness and execution all have to align.
This is particularly valuable in existing buildings, where structural engineering, practical buildability and municipal substantiation need to come together without noise.
Frequently asked questions
FAQ about structural calculations
Below are common questions from homeowners and property clients dealing with renovation, wall openings, extensions, roof works or permit review.
When are structural calculations required?
Structural calculations are required once an intervention affects the load-bearing structure, for example with a wall opening, extension, roof extension, floor opening or foundation alteration.
Are structural calculations mandatory for renovation work?
That depends on the intervention and the municipal review route, but for structurally relevant work they are often necessary for safety, permit review or execution feasibility.
Do I need a structural engineer when removing a load-bearing wall?
Yes, in almost all cases. The engineer determines how the loads are transferred and which structural provision is needed.
How much do structural calculations cost?
The fee depends on complexity, the available information, any required site assessment and the type of intervention. A simple wall opening is different from an extension on new foundation or a roof extension on an existing house.
How long does it take to prepare structural calculations?
That varies per project. Straightforward interventions can be worked out faster than combined renovation projects involving multiple structural parts or permit-related coordination.
Is a shoring plan always required?
No, but during demolition or temporary unloading of load-bearing parts, a shoring plan can be essential for safe execution.
Does an extension also require foundation advice?
Often yes. The added load needs to be assessed, and it must be checked whether the supporting foundation strategy is appropriate.
Can structural calculations be needed even without a formal permit?
Yes. Even without a permit trigger, calculations may still be necessary for safe execution, insurability and allocation of responsibility.
What is included in a structural report?
A structural report generally includes assumptions, loads, calculations, selected materials, explanation of the intervention and the technical basis of the proposed solution.
Can Aboss also help with drawings in addition to calculations?
Yes. Where useful, the structural engineering can be coordinated with architectural drawings and permit documents so the file remains technically coherent.
Ready for a technical review?
Need structural calculations for a renovation, alteration or permit application?
Send the project address, a short description and any available photos, sketches, drawings or PDFs. We review the likely structural relevance and respond with a practical route.
Related services
Relevant Aboss pages
These pages are closely connected to structural calculations for renovations, extensions and permit routes.