Office building structural engineering
Office buildings have to give flexible, column-light floors that stay comfortable underfoot and adapt as tenants change. We design office structures from the frame and floors to the stability and foundations, for developers and occupiers across the UK.
What floor system is best for an office?
It depends on the span, floor depth and services strategy. Composite steel and concrete floors give long spans at shallow depth with services through the beams, while concrete flat slabs give a clean soffit. We compare the options for your building and recommend the best fit.
Frames and floor systems
Modern offices are built around flexible floor plates, so the structure aims for long spans and few internal columns, letting tenants lay out and re-lay out the space freely. We design the frame, most often steel with composite floors, or reinforced concrete flat slabs, to carry the office imposed load and a partition allowance from BS EN 1991-1-1, and we set the grid to suit both the floor plate and the car parking or entrance below.
The floor system is chosen for span, depth and services. Composite steel and concrete floors give long spans at a shallow depth and let services run through cellular beams, while flat slabs give a clean soffit and shallow floor zone. We size the floors for strength and, just as importantly, for deflection and vibration, because an office floor that passes the strength check can still feel uncomfortably lively if the dynamic response is not controlled.
Stability, wind and movement
A multi-storey office has to resist wind and stay upright, and how it does that shapes the whole building. We provide stability through braced bays, concrete cores around the lifts and stairs, or moment frames, choosing the system that fits the architecture and carries the wind load to the foundations. Wind actions are calculated to BS EN 1991-1-4 and its UK National Annex, and for taller buildings we check sway deflection and inter-storey drift so the cladding and partitions are not damaged.
Movement of all kinds has to be managed. We allow for thermal movement, shrinkage of concrete and differential movement between elements, positioning movement joints where they are needed and detailing the cladding support so the facade can move relative to the frame without distress. On tall or slender buildings we also consider the human comfort criteria for wind-induced sway, so the upper floors do not feel uneasy in a storm.
Foundations, refurbishment and future change
The foundations follow the ground and the building height. For a low-rise office on good ground, pads or strips may suffice, while a taller building or poor ground calls for a raft or piles designed for the column and core loads. We design the foundations for the full combination of vertical load, wind uplift and the overturning that a tall building generates, and we allow for any basement or below-ground parking in the same scheme.
Much office work is refurbishment rather than new build, and here the skill is getting more from an existing frame. We appraise the existing structure, check it against modern loads and the proposed new use, and design the openings, strengthening, new cores or additional floors that a refurbishment or vertical extension needs. Reusing a sound frame saves cost and carbon compared with demolition, provided the appraisal is done honestly.
What we check.
The points our calculations resolve for a project like this.
- Long-span, column-light floor plates for tenant flexibility
- Floor vibration and deflection controlled for occupant comfort
- Stability by braced bays, concrete cores or moment frames
- Wind sway and inter-storey drift limited to protect cladding
- Movement joints and cladding support for thermal and shrinkage movement
- Appraisal and reuse of existing frames in refurbishment and extension
From enquiry to sign-off.
Enquiry
Send drawings or describe the problem. We confirm the scope, the deliverables and a target timescale.
Information
We agree the survey, drawings or data we need and any site access required.
Engineering
Design, calculation or assessment to the relevant Eurocodes and UK National Annex.
Issue
A clear, defensible report or set of calculations, with assumptions and limitations stated.
Common questions
What floor system is best for an office?
It depends on the span, floor depth and services strategy. Composite steel and concrete floors give long spans at shallow depth with services through the beams, while concrete flat slabs give a clean soffit. We compare the options for your building and recommend the best fit.
Why does floor vibration matter in offices?
An office floor can pass the strength check and still feel uncomfortably bouncy under walking. We design the floor for its dynamic response as well as strength, so it stays comfortable, which matters most on long-span, lightweight floors.
Can you add floors to an existing office building?
Often yes. We appraise the existing frame and foundations, check what spare capacity they have, and design the strengthening the extra floors need. Reusing a sound structure usually beats demolition on both cost and carbon.
Do you work on offices across the UK?
Yes. We design new and refurbished office buildings for developers and occupiers across the UK, with calculations delivered remotely and site visits arranged by region.
Related in commercial, industrial & agricultural structural engineering.
Tell us what you are building.
Send the drawings or describe the project. We confirm scope, deliverables and a realistic timescale.
Start a project