Structural reuse and retrofit appraisal
An appraisal of how much of an existing structure can be kept and reused, rather than demolished and rebuilt.
About this service
Before demolishing a building, it is worth asking how much of it could be kept. Existing foundations, frames and floors represent a large investment of material and carbon, and reusing them can save time, money and planning risk. Our appraisal examines an existing structure and sets out how much can be retained, what strengthening it would need, and where demolition is genuinely the better option.
Typical projects include converting offices or commercial units into flats, remodelling older houses, adding storeys to existing buildings, and redeveloping sites where the planning authority has signalled it prefers retention. Many London councils now expect applicants to justify demolition, and a structural appraisal gives that case a proper engineering basis rather than an assumption that new build is simpler.
We inspect the structure, review whatever drawings exist, and assess capacity and condition against the proposed new use. Where the original design is unknown, we recommend targeted investigation and opening-up to confirm key elements. All appraisal calculations go through our three-step quality control process, with final sign-off by our Head of Engineering, so the conclusions stand up to scrutiny from planners and lenders.
When you need it
- You're deciding between refurbishment and rebuild
- The planning authority favours retention
- You want to cut cost and carbon by reusing structure
What's included
- Inspection and review of the existing structure
- Assessment of capacity and condition
- Reuse and strengthening options
- Recommendations
How it works
- Understand the briefWe discuss the proposed use, layout changes and any extra storeys, because the new loads and openings decide how much of the existing structure can realistically be kept.
- Inspect and investigateWe visit the building, identify its structural form and assess condition across foundations, frames, floors, roofs and connections. Where records are missing, we specify opening-up or testing to fill the gaps.
- Assess capacityWe check whether the existing structure can carry the new loads, including partitions, plant and extra floors, and whether it meets current robustness expectations. Elements that fall short are identified.
- Develop optionsFor each shortfall we set out strengthening or partial replacement options, comparing practicality and, where useful, carbon. The report ends with a clear recommendation on what to retain and what to replace.
What you receive
When keeping an existing structure makes sense
Reuse works best when the structural form suits the new use. A concrete-framed commercial building often has generous floor capacity and column spacing that adapt well to flats. Victorian masonry houses are robust but may need new floors, steel openings and foundation checks when converted. Our guide to converting a house into flats covers the domestic side in more detail.
It works less well when the new layout fights the old structure. Moving every load path, digging a basement beneath existing walls or stacking new storeys onto shallow foundations can make retention more expensive than rebuilding. An honest appraisal identifies these cases early. Even then, keeping a facade, a basement box or a set of floors is often possible and still worthwhile.
Frequently asked questions
Is it cheaper to refurbish or rebuild?
Refurbishment is often cheaper, because the foundations and frame are already in place, but it depends on condition and how much the layout changes. Hidden defects, major strengthening or heavy alterations can erode the savings. A structural appraisal gives you the information to compare both routes properly before committing to a design or a planning strategy.
Why do councils prefer retaining existing buildings?
Demolition and rebuilding release a large amount of embodied carbon and create significant waste. Many councils have policies asking developers to consider retention first and explain why demolition is necessary. A structural appraisal shows whether retention is feasible and on what terms, which supports the planning case whichever way the answer falls.
Can an existing building take extra floors?
Sometimes. It depends on the capacity of the foundations, walls or frame, and on the ground beneath. Lightweight construction such as timber or light steel framing improves the chances. Once the appraisal confirms it is feasible, our additional storeys service covers the design, for buildings up to 15 metres and five storeys.
How much does a structural reuse appraisal cost?
Our structural reuse and retrofit appraisal starts from £1,500 + VAT. The final fee depends on building size, available records and whether opening-up or testing is needed. We confirm a fixed fee in writing before starting, and our typical turnaround is 10 working days.