Structural Survey Guide: When You Need One and What to Expect

A structural survey is an inspection of a building's structural integrity carried out by a qualified structural engineer. It assesses the condition of load-bearing elements — foundations, walls, beams, floors, and the roof structure — and identifies any defects, movement, or damage that could affect the building's safety or value.

A structural survey is different from a standard building survey (RICS Level 3). While a building surveyor examines the general condition of the property, a structural engineer focuses specifically on whether the structure is sound and what remedial work might be needed.

A typical structural survey involves:

Site visit and visual inspection — The engineer inspects all accessible structural elements: external walls, internal walls, floors, ceilings, the roof structure, and (where accessible) foundations. They look for cracking patterns, signs of movement, damp, timber decay, and evidence of previous alterations.

Crack monitoring (if needed) — Where cracks are present, the engineer may recommend installing crack monitors to track whether movement is ongoing or historic. Monitoring typically runs for 6–12 months, though shorter periods may suffice for straightforward cases.

Assessment of building history — The engineer considers the building's age, construction type, any visible alterations, and local ground conditions (particularly relevant for subsidence assessment on London clay).

Structural report — A written report is produced summarising the findings, diagnosing the likely cause of any defects, and recommending remedial action. The report typically includes:

• Description of the building's construction
• Summary of defects observed
• Analysis of cracking patterns and movement
• Assessment of cause (subsidence, settlement, thermal movement, overloading, etc.)
• Recommended remedial works with indicative costs
• Urgency assessment (immediate, short-term, monitoring)
• Photographs and diagrams

A structural survey is carried out by a structural engineer (CEng, MIStructE) and focuses on structural integrity and safety, providing deep analysis of structural elements where specific structural concerns have been identified. The output is an engineering report with remedial specification, typically costing £400–£1,000+.

A building survey (RICS Level 3) is carried out by a chartered surveyor (MRICS) and focuses on overall property condition, providing a broad assessment of all building systems for general pre-purchase assessment. The output is a condition report with maintenance advice, typically costing £500–£1,500+.

In many cases, both are valuable. A building survey gives you the full picture of the property's condition, while a structural survey provides definitive answers about specific structural concerns.

Structural survey costs in London typically range from:

• Simple inspection with report (e.g., crack assessment for a terraced house): £400–£600
• Comprehensive structural survey (e.g., full assessment of a period property): £600–£1,000
• Complex or large properties (e.g., commercial, multi-storey, or listed buildings): £1,000–£2,500+
• Crack monitoring (installation and 6-month reporting): £300–£600

When selecting a structural engineer for a survey, check:

• Qualifications: Look for Chartered Engineer status (CEng) and membership of the Institution of Structural Engineers (MIStructE) or Institution of Civil Engineers (MICE).
• Professional indemnity insurance: The engineer should hold current PI insurance covering the value of work they are advising on.
• Local experience: An engineer familiar with London's building stock, ground conditions, and typical defects will provide more relevant advice.
• Clear fee structure: The engineer should quote a fixed fee or clearly explained hourly rate before starting work.
• Report turnaround: Ask when you will receive the written report. Typical turnaround is 5–10 working days after the site visit.

Subsidence — London's clay soil shrinks and swells with moisture changes, causing foundation movement. Trees near buildings extract moisture and accelerate this process. Subsidence typically shows as diagonal cracking wider at the top than the bottom.

Settlement — All buildings settle to some degree after construction. Historic settlement in older properties is usually stable and cosmetic. An engineer distinguishes between ongoing and historic movement.

Lintel failure — Older properties may have timber or stone lintels above windows and doors that have deteriorated, causing cracking above openings.

Wall tie failure — Cavity wall ties can corrode over time, causing the outer leaf of the wall to separate from the inner leaf. This shows as horizontal cracking along mortar bed joints.

Roof spread — Where roof rafters push outward against the top of walls, causing the walls to lean. Common in older properties where the original roof structure lacks adequate ties.

Timber decay — Rot or beetle infestation in structural timbers (floor joists, roof timbers, lintels) can weaken the structure.

Removal of load-bearing walls — Previous owners may have removed walls without adequate structural support, transferring loads in unintended ways.

1. Instruction — Contact a structural engineer, describe your concerns, and agree the scope and fee.

2. Desktop review — The engineer may review available information before visiting: title plans, any previous survey reports, building control records, mining reports, or tree surveys.

3. Site visit — The engineer visits the property (typically 1–3 hours depending on size and complexity) and carries out a thorough visual inspection.

4. Analysis — The engineer analyses their findings, considering construction type, ground conditions, loading, and any movement patterns.

5. Report — A written report is issued within 5–10 working days, setting out findings, diagnosis, and recommendations.

6. Follow-up — If remedial work is needed, the structural engineer can design the solution (steelwork, underpinning, wall ties, etc.) and provide drawings for building control and your contractor.