Structural engineering

The following situations commonly trigger a requirement for structural design, though the specific threshold always depends on the building and should be confirmed with Building Control.

An engineer's foundation design is only as good as the ground information it is based on. Where ground conditions are uncertain — variable fill, soft clay, historic mine workings, sloping sites, or cracking in an existing building that might indicate movement — a site investigation or trial pits inform the design rather than relying on assumption.

On sloping sites, foundations often need stepping, and retaining structures may be needed to manage level changes safely, both of which are structural design decisions with real cost consequences that are best resolved before pricing starts.

An engineer's package typically moves through a few stages: a structural concept, then detailed calculations, then construction drawings and schedules that a contractor can actually build from. The construction-ready information is what SHS needs to price and build a job accurately — a structural concept alone is not enough to quantify concrete, steel or reinforcement.

A complete structural information pack for pricing and construction usually includes the following.

An engineer's design process typically starts with the loads a structure has to carry — the weight of the building itself, imposed loads such as furniture and occupants, and environmental loads such as wind and snow. Those loads are traced down through beams, walls and foundations to the ground, and the ground's bearing capacity then sets how wide, deep or reinforced the foundation needs to be.

For steel, the same logic applies in reverse: a beam is sized to carry the load spanning between its supports without excessive deflection, and the connections and padstones at each end are designed to transfer that load safely into the wall or column below. None of these figures can be guessed accurately from a floor plan alone, which is why a structural concept sketch and a fully engineered set of calculations produce very different levels of pricing confidence.

Certain structural situations come up repeatedly in Cumbria's mix of extensions, barn conversions and rural new builds, and each brings its own engineering considerations.

A site investigation — trial pits, or boreholes for larger or more sensitive sites — gives an engineer real information about the ground: soil type, bearing capacity, water table depth and, where relevant, evidence of past mining or made ground. Designing without this and relying on assumed ground conditions is common on straightforward sites, but it shifts risk onto the foundation being changed once excavation reveals what is actually there.

On sites with any history of instability, nearby mine workings, or unusually soft or variable ground, the cost of a site investigation is generally small compared with the cost of redesigning and re-pricing a foundation midway through excavation.

Structural design does not stop at the finished building — many jobs need a temporary works design for the construction phase itself, covering how an opening is propped while a beam is inserted, how a trench is supported if it is deep or in unstable ground, or how a partially demolished structure is braced before rebuilding. Temporary works are a specific engineering discipline, and the sequence they describe is not optional — it exists because getting it wrong risks collapse during construction, not just a defect after completion.

SHS is the contractor, not the planning authority. What SHS can do is look at the structural elements from a build point of view — access, ground conditions, levels, drainage, foundations and buildability — and tell you plainly what the construction side is likely to involve.

If drawings already exist, send them. If they do not, a site visit and a conversation usually establishes what information you need to gather next and who you need it from.