Complete structural design for extensions and loft conversions — foundations, steelwork, beam calculations and the drawings your builder prices and builds from.
Your architect draws what the extension looks like; the structural engineer makes it stand up. Structural design for extensions and loft conversions turns planning drawings into the beams, foundations and connection details a builder can price accurately and building control can approve first time.
What the design covers
- Single and double-storey extensions — foundation design (including near trees and on clay), ridge and valley beams, roof structure, and the large-opening steelwork that bi-folds and kitchen islands demand.
- Loft conversions — floor beam design, dormer framing, hip-to-gable steelwork, purlin and rafter checks and stair trimming, coordinated with the building control calculation pack.
- Basements and structural remodelling — scoped individually with the right specialist input.
- Party wall coordination — where beams bear into shared walls or excavation runs within notifiable distances, our party wall surveyors handle the Act alongside the design.
Why early structural input saves money
The expensive extension mistakes happen before anyone builds anything: foundations priced as a guess and re-priced on site, steel ordered twice, a design that ignores what the existing house can carry. Involving the engineer at drawing stage — not after tender — means the builder prices certainty. It also keeps the project honest against ground conditions: on shrinkable clays with mature trees nearby, foundation depth is a design decision, not a site improvisation (subsidence risk we know well from our investigation work).
Fees and timescales
Fixed fees quoted from your architect's drawings; design and calculations typically 1–2 weeks depending on scope. Need the wider project run too? Our construction project management team takes it from design to handover.
Frequently asked questions
Do I need a structural engineer for my extension?
Almost certainly — any extension involves foundations, and most involve steelwork over openings and new roof structure, all of which building control expects to see engineered. Your architect handles layout and planning; the structural engineer makes it stand up and proves it on paper. The two work from the same drawings, and we're happy to liaise with your architect directly.
When should the structural engineer get involved?
At drawing stage, before tender — not after a builder has priced the job. Early structural input means foundations, steel and connection details are defined when builders quote, so prices are comparable and the contingency for "unknowns" shrinks. Bringing the engineer in late is how projects end up re-pricing steel mid-build.
Do you work alongside my architect?
Yes — that is the normal arrangement. The architect provides the planning and layout drawings; our engineer designs the structure to suit and produces the calculations and structural details building control requires. Your engineer communicates with your architect and builder directly, so you are not relaying technical queries between professionals.