Home Extension Structural Design London
Home Extension Structural Design London is needed when creating new kitchens, rear extensions, side returns or multi-room additions. Builders and homeowners rely on accurate structural calculations so the extension ties safely into the existing house and passes Building Control without delays.
What this service includes
Complete extension structural design package
You receive a full structural pack tailored to your extension:
- Steel beam and frame design for openings and roof loads
- Foundation sizing for London clay, mixed ground or reinforced slabs
- Load assessment for walls, roofs and floors
- Padstone and bearing design
- Connection details for beams, posts and lintels
- Wind stability and lateral support checks
- Structural drawings for your builder
- Building Control calculation pack
- Support during approval and construction
Why extensions in London need proper structural design
London homes vary widely. Victorian terraces often need beams to support rear openings and shallow floors. 1930s semis have cavity walls that need stronger bearings. Post-war houses can have lightweight roof structures. Many properties have older alterations that change the load paths. A safe extension needs a design that fits your house type, ground conditions and roof layout.
Common issues homeowners face
- Existing walls too weak to carry new openings
- Poor ground conditions or soft clay
- Irregular floor levels creating uneven load paths
- Neighbouring extensions affecting drainage runs
- Roof shapes requiring additional steelwork
- Limited space for deep beams or posts
- Hidden defects found during demolition
How we work (24–48hr process)
Straightforward engineering flow
Technical section
Foundation design
London ground ranges from firm clay to mixed made-up soil. We size strip foundations, pads or reinforced slabs depending on depth and bearing strength.
Opening and beam design
Large bi-folds and open-plan rooms require beams or small frames. We check bending, shear and deflection using Eurocode 3.
Roof loads
Flat roofs, pitched roofs and hybrid systems each load the structure differently. We design joists, rafters or steelwork to carry these safely.
Lateral stability
Extensions can weaken the existing house if walls are removed. We check stability, bracing and wind resistance.
Bearing design
Clay brickwork and older masonry often need padstones or steel plates to spread loads and prevent cracking.
Building Control requirements
What Building Control expect
- Full structural calculations
- Beam, column and foundation sizes
- Load path and stability checks
- Deflection and serviceability limits
- Bearing and padstone details
- Clear drawings for inspection
You can read more about structural rules in: Approved Document A (gov.uk)
Price guide
Small extension
£350 - £500 (Single opening)Medium extension
£500 - £900 (Multiple beams/larger spans)Larger projects
£900 - £1,500 (Complex roofs, mixed ground)Payment Terms: You pay 50 percent upfront and the balance when the full calculation pack is complete.
Local London examples
Real extension projects we complete often
Why choose us
- Clear structural drawings
- Fast 24–48hr turnaround
- Local knowledge of London house types
- Builder-friendly documents
- Fair fixed pricing
- Direct access to senior engineers
Areas we cover
FAQs
- Head Office: Corwell Lane, Uxbridge, England, UB8 3DE.
- 07359 267907
- info@structuralengineercalcs.com
- Company No: 12653163