Home extensions • Structural engineer
Structural engineer for extension projects across the UK. We design RSJ beams, steel frames and foundations for single storey, double storey, side and wrap-around extensions, with clear drawings your builder can follow on site.
We work with homeowners, architects and builders across the UK, providing home extension structural design and calculations that keep projects moving and satisfy Building Control.
From simple single storey rear extensions to full wrap-around schemes, we focus on safe, buildable steelwork and foundations that work with your property.
RSJ beams and padstones for wide openings to the garden, with roof and wall loads checked into the existing structure.
Structural design from foundations up, checking walls, floors and roof loads along the full load path.
More complex extensions where rear and side elements meet, often needing frames and cranked beams.
A clear scope and good information mean a smoother design and fewer queries from Building Control.
For most standard home extensions where we design RSJs, frames and foundations, structural calculation packages usually fall within a clear fixed fee range. The exact figure depends on the number of beams, storeys above, and how complex the existing structure is.
Figures here are a guide only. We always confirm a fixed fee in writing once we have seen your plans and photos so you know the cost before we start any calculations.
A few comments from homeowners who asked us to handle the structural side of their extensions.
“Clear drawings, quick turnaround and no hassle with Building Control. Our rear extension steelwork was approved first time and the builder said the layout was easy to follow.”
“We had a double storey side and rear extension with a big knock-through. The engineer explained the goalpost frame in simple terms and dealt with all structural questions from Building Control.”
“Good communication from start to finish. We sent drawings on Monday and had the calculation pack ready to submit within two days. Fixed fee and no extras added later.”
“Our project involved underpinning and poor ground. The team were patient, explained the options and updated the design when site conditions changed.”
A quick overview of timing, information needed and how Building Control uses our extension packs.
Yes. If your extension involves new openings, RSJs, frames, foundations or changes to load bearing walls, Building Control will expect structural calculations from an engineer. For very small projects we will advise you honestly if calculations are not needed.
Straightforward single storey extensions are often turned around within 24 to 72 hours once we have clear information and payment. Larger or more complex projects may take longer. We confirm the timeframe before you commit.
Often yes. Good photos and basic measurements are enough to give a guide fee and sometimes to start design. If we need more detail, we explain exactly what to send in a short checklist.
Our calculations follow current UK design codes and are set out in a format Building Control officers are used to. If your officer has questions, we answer them directly and make any minor clarifications needed.
Use this form to outline your extension. Your enquiry goes straight to an engineer, not a call centre.
Share a few details so we can review the layout and confirm the right scope and fixed fee for your home extension structural calculations.
This form connects to our central SECalcs email. You will usually hear back from a structural engineer within one working day.
If you are planning a home extension and want clear structural calculations for RSJs, frames and foundations, send us a few details and we will confirm the next steps and a fixed fee.
