What Is a Structural Survey?
A structural survey (formally a RICS Level 3 Home Survey or Full Building Survey) is a detailed inspection of a property's condition, structure, and fabric. It is the most thorough survey type and is recommended for:
- Older properties (pre-1950, and especially pre-1919)
- Properties that have been extended, converted, or significantly altered
- Properties in visibly poor condition
- Non-standard construction (timber frame, concrete, steel frame)
- Listed buildings
- Any property where the buyer intends to carry out works
It is distinct from a homebuyer's report (RICS Level 2), which is less detailed, and a mortgage valuation, which is not a survey at all.
The RICS Traffic Light System
Most structural surveys use RICS condition ratings:
- Condition 1 (Green): No repair is currently needed
- Condition 2 (Amber): Defects that need repairing or replacing — not serious or urgent
- Condition 3 (Red): Defects that are serious and/or require urgent attention
Some surveyors use NI (Not Inspected) for areas not accessible during inspection and N/A (Not Applicable) for elements not present.
Important: A Condition 3 finding does not automatically mean the deal is dead. It means the item requires urgent professional assessment and likely remedial work. The cost of that work can often be negotiated against the purchase price.
Key Sections of the Report
Structure
This covers:
- Roof structure: Condition of rafters, purlins, ridge, wall plates, evidence of movement or rot
- Chimney stacks: Pointing condition, stack stability, DPCs and flashings
- External walls: Cracks, bowing, settlement, rendering failure, pointing
- Floors: Movement, timber condition, evidence of woodworm or rot, adequacy of ventilation below suspended timber floors
- Internal walls: Cracks (diagonal or step cracks may indicate movement), partition condition
- Cellar/basement: Damp, structural condition, drainage
External Fabric
- Roof coverings (tiles, slates, flat roof membrane)
- Rainwater goods (gutters and downpipes — a common source of damp when blocked or leaking)
- Windows and doors — condition of frames, glazing, seals
- External decoration and render
Services
Structural surveys typically comment on but do not test services (electrics, gas, plumbing). They will flag where a specialist inspection is recommended (e.g., EICR for electrics, gas safe certificate for gas).
Legal and Planning
Surveyors often flag observations relating to:
- Extensions that may not have had building regulations approval
- Loft conversions without a completion certificate
- Evidence of alterations that may have planning implications
These are flagged as matters requiring legal clarification, not structural defects per se.
How to Interpret Cracks
Not all cracks are serious. Surveyors assess:
- Width: Fine hairline (less than 0.1mm) vs. significant (3mm+)
- Pattern: Diagonal/step cracks (structural movement), horizontal (lintel or wall plate failure), vertical (thermal expansion, less serious)
- Location: At openings (common), at corners (movement at junctions), in the middle of walls
- Activity: Is the crack growing? (usually assessed with monitoring over time, not in a single survey)
A widespread pattern of diagonal cracks at window corners, especially with door and window binding, warrants further investigation for subsidence or heave.
What to Do After the Survey
- Read the full report — do not just look at the executive summary
- Identify all Condition 3 items and any items flagged as requiring specialist investigation
- Obtain quotes for the Condition 3 items before exchanging contracts (a provisional quote is enough to calibrate the negotiation)
- Consider instructing a specialist for specific items: a structural engineer for movement concerns, a damp specialist for moisture, a drainage survey for drainage issues
- Decide whether to proceed, renegotiate, or withdraw
RCB Design & Build
RCB provides pre-purchase technical reviews and post-survey project planning support for London homeowners. We help clients translate survey findings into a prioritised programme of remedial works and integrate that into a wider refurbishment plan.