What Is a Party Wall Monitoring Survey?
A party wall monitoring survey (also called building movement monitoring) is the ongoing inspection of a neighbour's property during construction work to detect any movement, cracks, or damage caused by the works. It is used for extensive works (basements, underpinning, deep excavations, pile foundations) where significant movement risk exists.
Reflective targets are installed on walls and measured with electronic distance meters to ±1mm accuracy. Crack gauges and vibration sensors may also be used. A base reading is taken before work starts, with continued monitoring after completion until settlement ceases.
Costs (Hounslow/London 2025)
| Service | Typical Cost (ex VAT) | | --- | --- | | Initial installation visit | From £75 per visit | | Monitoring visit + report | £354–£630 per visit | | Schedule of Condition (baseline) | £300–£600 per adjoining property | | Party Wall Award (legal document) | £700–£1,500 per award | | Party Wall Notice | £50–£150 per notice |
For a simple extension or loft conversion in Hounslow, expect £500–£2,000 total (notice + SOC + award). Continuous monitoring for complex works (basements) may run 18–24 months.
The building owner typically pays all surveyor costs if works are for their benefit.
Deliverables
- Schedule of Condition report — Date-stamped photos and written descriptions of existing cracks and defects before work starts
- Monitoring reports — Each visit produces written report with measurements showing any movement
- Party Wall Award — Legal document setting out rights, obligations, trigger levels, monitoring requirements
- Final inspection report — Confirms whether movement ceased and defects to remedy
Hounslow Coverage
We provide party wall monitoring surveys throughout the London Borough of Hounslow including:
- Hounslow, Brentford, Isleworth, Chiswick
- Feltham, Cranford, Heathrow, Heston
- Whitton, Teddington, and all surrounding TW postcode areas
Frequently Asked Questions
Q: When do I need party wall monitoring in Hounslow?
You need party wall monitoring when carrying out high-risk works near neighbouring properties — particularly basement excavation, deep foundations, underpinning, or piling. It is typically specified in the Party Wall Award.
Q: What are trigger levels?
Trigger levels are pre-agreed movement thresholds. If readings approach or exceed these levels, the structural engineer is notified immediately so corrective action can be taken before damage occurs.
Q: How often are monitoring visits?
Frequency depends on project phase and risk profile. Typical schedules include daily visits during active excavation, weekly during construction, and monthly during post-construction monitoring.