Construction Impact on Occupied Buildings
Independent indoor air quality assessors · Since 1999
Construction or refurbishment can affect occupied commercial areas through airborne particles, tracked material and contamination of ventilation pathways. A construction-impact programme establishes conditions before work, monitors the occupied building during higher-risk activities and verifies condition after completion. It is commissioned by landlords, occupiers or contractors who need an agreed evidence route for protecting operations and resolving alerts. The emphasis is the receiving building; site-perimeter emissions are handled separately through Boundary Monitoring Services.
Established 1999 · 2,500+ assessments · SafeContractor approved · BOHS Affiliate Member · London & South East
Baseline before disturbance begins
Pre-works monitoring records normal particulate patterns in representative occupied rooms, sensitive zones and relevant outdoor or intake locations. We document occupancy, cleaning, ventilation operation, nearby traffic and other activities that could affect readings. Existing deposits, filter condition and known concerns are also recorded. The baseline is designed around the planned works and building pathways, giving later data a meaningful comparison rather than assuming all change comes from construction.
A monitoring plan tied to the works
The plan identifies activities likely to generate dust, programme stages, working hours, separation measures and communication contacts. Real-time optical monitors can be positioned in occupied areas near interfaces and at suitable comparison points. Activity logs let peaks be checked against demolition, cutting, deliveries, cleaning or unrelated building events. Monitoring periods cover the work phases most likely to test containment, with data review arranged to fit the client's management process.
Agreed alert levels and response
Alert levels are agreed with the client for the project, drawing on baseline behaviour, selected guidance, instrument response and the sensitivity of the occupied use. An alert is a management trigger rather than automatic proof of source. The response can include checking activities and barriers, reviewing indoor and comparison trends, inspecting doors or intakes, and asking the contractor to adjust controls. Escalation contacts and documentation are set before monitoring starts so evidence leads to timely action.
Protecting HVAC intakes and filters
External intakes, temporary openings, pressure relationships and shared plant can create pathways into occupied areas. We review their relationship to the works and record accessible filter condition or loading. The project team may need to relocate dusty tasks, improve containment, alter work sequencing or ask the HVAC contractor to review filtration and controls. Green Air Monitoring assesses the environmental evidence; mechanical changes remain under the responsible designer or contractor.
Internal refurbishment interfaces
Where construction occurs within an occupied building, floor zoning, hoardings, lift use, waste routes and cleaning boundaries become important. Monitors are placed to test containment at occupied interfaces while comparison points show wider building conditions. The scope can include deposition checks where surface cleanliness matters. Occupancy and building operations are kept in the record because a closed floor and a busy office provide different contexts.
Post-works clean verification
After work and cleaning, a documented inspection can compare selected surfaces, occupied-space particulate patterns and accessible filtration with the baseline or agreed completion criteria. Verification is planned after dust-generating activity has ended and cleaning is complete. It records residual concerns and whether further contractor action or repeat measurement is justified; it does not replace the contractor's own quality-control responsibilities.
Is this the right page?
Choose this service to protect an occupied building receiving potential construction impact. Boundary Monitoring Services covers measurement around the construction-site perimeter. Indoor Particulate Investigation is better where elevated readings already exist but their source is unclear.
Limitations and what this assessment cannot tell you
Construction attribution depends on baseline quality, monitor placement and reliable activity records.
- An alert identifies a condition requiring review, not automatic proof of responsibility
- Optical particulate monitors do not identify material composition
- Weather, traffic, occupancy and unrelated activities may influence patterns
- Internal monitoring is distinct from statutory or contractual site-boundary monitoring
- Construction controls, HVAC changes and cleaning are implemented by the appointed teams
What the works-impact record includes
- Pre-works baseline and existing-condition observations
- Monitor locations, operating context and project interfaces
- Time-series particulate results linked to activity logs
- Alert events, investigations and recorded responses
- HVAC intake, filter and containment observations
- Post-works verification and unresolved actions
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Frequently Asked Questions
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