As soon as the load path, stability or loading of a building changes, it must be shown that the new situation is structurally sound. We make structural calculations that suit the available data and record which starting points, assumptions and checkpoints apply to your plan.
For load-bearing walls, beams, portal frames, floors, roofs and foundations
Also when building drawings are missing or inaccurate
Calculation and drawings match each other and the design
Six situations where a calculation provides the answer
For a change to the load-bearing structure of a house, apartment or other existing building. It is clear in advance what can and cannot be soundly justified.
01 / Opening
Removing or opening up a load-bearing wall
For an opening in a load-bearing wall, we investigate how the load is taken over and which beam, lintel or portal frame is suitable.
02 / Steel
Installing a steel beam or portal frame
For a new span, we calculate load-bearing capacity, bearings and connections, matched to the existing structure.
03 / Stability
Stability after the alteration
If walls, floors or roof parts provide bracing or diaphragm action, we assess whether stability is maintained after the intervention.
04 / Foundation
Foundation and extra load
With a heavier load, signs of settlement or doubts about the subsoil, a foundation assessment can be part of the process.
05 / Floor and roof
Floor, roof, stair opening or void
For changes to a floor or roof, we map out the effect of new loads, openings, trimming and strengthening.
06 / Incomplete information
Existing buildings without good drawings
If drawings are missing or differ from reality, we work with a survey, archive research and explicitly recorded assumptions.
A well-founded start
What does a structural justification include?
A photo or rough floor plan is usually not enough. The process often consists of a survey, drawing, calculation and an explanation of the assumptions and limitations.
Components
Structural survey: recording the existing situation, with visible load paths, bearings, cracks and deviations
Drawings: floor plans, elevations, sections and details as the basis for the calculation model
Calculations and load overview: the relevant loads, spans, combinations and checks per element
Explanation of the starting points: which assumptions were used, where uncertainties lie and when further investigation is needed
Calculations are made in accordance with the relevant structural standards. The scope depends on the building, the intervention, the available data and the purpose of the documents.
The calculation on paper
Structural drawing: the calculation made visible
The structural calculation shows that an element is strong and stiff enough. The structural drawing shows exactly what has to be built.
What it shows
The position and size of new beams, columns, lintels and portal frames
Profiles and materials, such as the steel section or the cross-section of a timber beam
Bearings, connections and, where needed, temporary support during demolition
References to the calculation, so drawing and calculation match
A structural drawing for your house or home is often part of the permit application and is the starting point for construction and fabrication for the contractor or steel fabricator. Looking for the original structural drawing of your home? It is sometimes in the building file. Requesting building drawings and the building file
First the existing situation, then the structural concept and then the calculation. When information is limited, we record which parts are certain and which still need to be checked.
Intake and scope
What changes, which part of the building is involved, and is the calculation intended for the permit, for construction or for a first feasibility check?
Survey and data check
We collect available drawings, photos and archive documents and check on site what is visible and measurable.
Structural modelling
Load path, spans, bearings and elements are translated into a model that can be calculated.
Calculation and verification
The relevant elements are checked for strength, stiffness and stability.
Report and next step
The outcome is recorded with assumptions, limitations and any next steps towards the competent authority or construction.
Getting started
What can you send us?
A complete file is not needed to discuss your question. With the right basic information we determine whether a calculation is possible straight away or whether a survey is needed first.
Checklist
Address and year of construction of the building
A short description of the alteration or opening
Photos of the inside and outside
Available building drawings or archive documents
Information on cracks, subsidence or earlier changes
What you need the outcome for: permit, construction or a first assessment
Which activity, consent or technical justification is needed depends on the plan, the location and the existing situation. The permit check (Vergunningcheck) in the Omgevingsloket gives a first indication; the competent authority assesses the application. Even if you do not need a permit, the technical requirements of the Buildings Decree (Bbl) still apply, such as structural safety.
Do I always need a structural calculation to remove a load-bearing wall?
Usually yes, because the load has to be carried in a different way. What exactly is needed depends on the project and on the assessment by the competent authority.
Can a calculation be made when building drawings are missing?
Often yes, based on a survey, archive research and explicitly recorded assumptions. If the existing situation cannot be established well enough, further investigation may be needed.
What is the difference between a beam calculation and a portal frame calculation?
A beam calculation focuses on one or more load-bearing beams and their span. A portal frame calculation also includes the posts, the connections and the behaviour of the structure as a whole.
When is a stability assessment also needed?
When walls, floors or roof parts do not only carry loads but also contribute to the bracing or diaphragm action of the building. After a change, it must be checked that stability is maintained.
Is a structural calculation the same as a permit application?
No. The calculation is a technical justification, not a procedure. Whether and how an application is needed depends on the plan and the location; the competent authority assesses the application.
What if the existing structure turns out to be different than expected?
Then the calculation must be adjusted or supplemented with an extra survey or check. The outcome is only reliable within the recorded starting points and the observed situation.
What is a structural drawing?
A drawing of the load-bearing structure that belongs to the structural calculation. It shows, among other things, the position and size of beams, columns and portal frames, the profiles, the bearings and the connections.
