EXTENSION STRUCTURAL DESIGN
A coordinated structural package for a smoother build.
Structural design for rear, side and wraparound extensions, including openings to the existing house, roofs, foundations and stability where required.
GUIDE FEE
From £1,250 + VAT
TYPICAL PROGRAMME
Typically 5 to 10 working days
BEST FOR
Single-storey and two-storey home extensions
WHAT THIS SERVICE DOES
The new space should feel effortless. The load path connecting it to the home is not.
Extension structural design coordinates the foundations, walls, beams, columns, roofs and openings needed to add new space to an existing property. It also considers stability and the interface between new work and the original building.
Why it is required
It is required because an extension introduces new loads, removes parts of the existing envelope and depends on ground conditions that cannot be judged from the finished plans alone. Early engineering can avoid excessive steel and difficult site changes.
The client imagines light, space and family life. The engineer protects that ambition by resolving what sits in the ground, inside the walls and above the ceiling before it becomes expensive to change.
What you receive
01
Foundation strategy
Strip, pad or local foundation design informed by ground, trees, drainage and the existing building.
02
Superstructure design
Beams, columns, walls, lintels and roof members sized as a coordinated system.
03
Build-ready information
Calculations and drawings aligned with the architectural layout and Building Control submission.
BEHIND THE FINISHES
What your engineer is tracing before the work disappears.
Structural engineering is largely about understanding the elements a finished home will conceal. These are the decisions that protect safety, comfort, approvals and the cost of changing course later.
01
Foundation depth
Ground, trees, drains and nearby structures that influence the support strategy.
02
The opening to the house
Beams, posts and bearings required where the original rear or side wall is removed.
03
Roof load path
Rafters, joists, beams and restraint hidden above the final ceiling.
04
New-to-existing junction
Movement, levels and connections where two different structures meet.
A straightforward route from brief to build.
01 Share the address, proposed works and any drawings or photographs.
02 We confirm scope, fee, information needed and whether a visit is appropriate.
03 Your engineer delivers the agreed information and supports reasonable review queries.
PLAN THE WHOLE PROJECT
Connected structural decisions should be resolved together.
Many projects need more than one isolated calculation or visit. Explore the linked services below, or share the complete brief so the right scope can be confirmed once.
Structural calculations
Check the foundations, beams, walls and roof as one coordinated system.
Explore this service
Structural drawings
Give contractors clear positions, levels and structural details.
Explore this service
Civil engineering
Coordinate drainage, external levels and small-project infrastructure.
Explore this service
Questions, answered clearly.
When should the structural engineer join the project?
Ideally once the architectural layout is stable but before tender. Early input can avoid awkward spans, excessive steel and late coordination changes.
Do you design temporary works?
Permanent works are covered by the agreed scope. Temporary works and sequencing remain the contractor’s responsibility unless specifically commissioned.
Get clarity on scope, fee and next steps.
Submit the project information through the quote form for an engineer-reviewed scope and fixed-fee proposal.