Modular and MMC structural engineering
Modular and modern methods of construction move most of the build into a factory, which changes what the structure has to resist and when. We provide the module, interface and foundation engineering that makes offsite construction work on site, for manufacturers, developers and contractors across the UK.
How is modular structural design different from traditional?
A module is designed for manufacture, lifting, transport and stacking as well as its in-service loads, and the worst case is often craneage or transport. The assembled building also needs a stability structure and carefully detailed inter-module connections.
Designing structure that is built offsite
Modular construction turns a building into a set of factory-made volumetric modules or panels that are assembled on site, and that shifts the structural problem in an important way: the module has to survive stages a traditional building never sees. As well as the in-service loads of the finished building, a module is designed for manufacture, lifting, transport and stacking, and the worst load case is often craneage or a lorry over a rough road rather than the finished structure standing still.
We design the volumetric module or the panellised system, whether light gauge steel, hot rolled steel, cross laminated timber or a hybrid, so it is stiff enough to be lifted and transported without racking or damaging its finishes, and strong enough once stacked to carry the modules above. The lifting points and the temporary bracing that keep a module square during the crane lift are part of that design, not an afterthought for the factory. Designing for these temporary conditions early avoids modules that arrive on site cracked or out of square.
Stacking, stability and the overall building
Once modules are stacked, the assembled building still has to behave as one structure, resisting wind and stabilising the stack, and modules alone rarely do that without help. We design the overall stability, often a separate steel or concrete stability structure, a core or braced frame that the modules connect to, and the connections between modules that tie the building together vertically and horizontally.
The tolerance and the connection detail between modules is where modular projects succeed or fail, because a factory build and a site build have to meet within workable limits. We set out the inter-module connections, the tolerances and the tie details so the assembled building is a coherent structure and not just a stack of boxes, and we check the disproportionate collapse requirements for taller modular buildings.
Foundations, interfaces and coordination with the factory
Modular construction only saves time if the site is ready when the modules arrive, so the foundation and the ground floor interface are on the critical path. We design a foundation set out and levelled to the tight tolerances the modules need, since a module cannot absorb the variation a bricklayer can, and we detail the interface where the factory product meets the site-built substructure.
This work needs close coordination with the module manufacturer's own engineering, because responsibility is shared between the factory design and the site design and the two have to align exactly. We agree early who designs which element, how the modules land and level on the substructure, and how the connections are made and inspected once a module is craned into place and no longer easy to reach. The calculations follow the Eurocodes and Approved Document A, and we deliver to manufacturers, developers and contractors anywhere in the UK, with site visits arranged by region.
What we check.
The points our calculations resolve for a project like this.
- Module design for manufacture, lifting, transport and stacking
- Craneage and transport load cases, not just in-service loads
- Overall stability structure for the assembled building
- Inter-module connections, tolerances and tie details
- Foundations set out to tight modular tolerances
- Coordination with the module manufacturer's engineering
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
How is modular structural design different from traditional?
A module is designed for manufacture, lifting, transport and stacking as well as its in-service loads, and the worst case is often craneage or transport. The assembled building also needs a stability structure and carefully detailed inter-module connections.
What load cases matter most for a module?
Often the temporary ones. Lifting, transport over rough roads and stacking can govern the design more than the finished building standing still, so we design the module to survive those stages without racking or damage.
Do you coordinate with the module manufacturer?
Yes. Responsibility is shared between the factory design and the site design, so we coordinate closely with the manufacturer's engineering and align the two, particularly at the foundation interface.
Do modular foundations need to be more accurate?
Yes. Modules cannot absorb the variation a traditional trade can, so the foundation and ground floor have to be set out and levelled to tight tolerances, which we design and detail for.
Related in new build & development 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