Self-build structural design
Self-builders carry the design decisions themselves, so clear structural advice makes the difference between a smooth build and a costly one. We provide the foundation and superstructure design and the guidance behind it, for self-builders across the UK.
Do I need a structural engineer for a self-build?
Yes. A self-build needs designed foundations, a designed superstructure and stability, all assessed by Building Control, and a structural warranty provider will also require engineered calculations. We prepare a package that satisfies both.
Structural design for people managing their own build
Self-build is different from a developer scheme because you are the client, the project manager and often on site yourself, so the structural information has to be clear enough to hand to trades and to price accurately. We design the foundations, the superstructure and the stability of the house, and we explain the decisions in plain terms so you understand why a beam is the size it is and what the groundworker has to achieve before the walls go up.
We size the ridge, purlins and rafters, the floor joists or engineered joists, the lintels and beams over openings, and the steel picking up any first floor over open-plan space, then set it all out on drawings a trade can build from. We keep deflection on the long-spanning members within limits that protect plaster, glazing and floor finishes, since a beam that is strong enough but too lively still cracks the ceiling below. Because self-builders often change the design as they go, we keep the calculations tied to the current layout and revise them when you move a wall rather than letting a mismatch reach the site.
Foundations, ground and warranty
The foundation is where a self-build most often meets an unexpected cost, so it is worth getting right first. We assess the soil, the water table, the slope and any trees, use trial holes or a soil report where you have them, and design a strip, trench-fill, raft or piled foundation to suit. On a sloping or awkward plot the foundation and the ground floor decision, beam and block or ground-bearing slab, often shape the whole build cost, and we set them out early so there are no surprises when the digger arrives.
Most self-builds need a structural warranty for mortgage and resale, and warranty providers require engineered foundations and calculations. Our package is prepared so it satisfies both Building Control and a warranty surveyor, which avoids duplicated work and a stalled build.
Choosing a build system and satisfying Building Control
Self-builders choose between masonry, timber frame, structural insulated panels and ICF, and each has a different structural logic. We design in your chosen system or advise on the trade-offs, and where you use a frame or panel supplier we coordinate our foundation and stability design with their kit design so the two meet correctly at the ground floor and the roof.
The calculations are prepared to the Eurocodes, the relevant UK National Annex and Approved Document A for the full plans submission. We deliver calculations and reports to self-builders anywhere in the UK, and arrange a site visit by region where the foundation or the ground needs a look before the pour.
What we check.
The points our calculations resolve for a project like this.
- Clear, buildable calculations you can hand to trades and price from
- Foundation design from soil, slope, trees and trial holes
- Ground floor choice, beam and block or ground-bearing slab
- Coordination with a timber frame, SIPs or ICF supplier's design
- A package that satisfies both Building Control and a warranty surveyor
- Revisions kept in step as the self-build design evolves
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
Do I need a structural engineer for a self-build?
Yes. A self-build needs designed foundations, a designed superstructure and stability, all assessed by Building Control, and a structural warranty provider will also require engineered calculations. We prepare a package that satisfies both.
How much does self-build structural design cost?
Our fee starts for the foundation and superstructure calculations and drawings on a typical self-build, agreed as a fixed price once we have seen the plans. The size and complexity of the house set the final figure.
Will your calculations satisfy my warranty provider?
Yes. We prepare the foundation and structural calculations so they meet both Building Control and a warranty surveyor's requirements, which avoids duplicated work and delay.
Can you work with a timber frame or SIPs kit?
Yes. We design the foundation and stability and coordinate with your frame, SIPs or ICF supplier's design so the systems meet correctly at floor and roof level.
What if I change the design partway through?
We keep the calculations tied to the current layout and revise them when you move a wall or an opening, so a mismatch does not reach the site and cause abortive work.
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