Architect Site Inspections: Frequency, Purpose and What to Expect

Introduction

One of the most common misunderstandings between homeowners and architects concerns what architect "supervision" during construction actually means. Many homeowners expect their architect to be present on site continuously, checking every aspect of the contractor's work in real time. In reality, the architect's standard role during construction is periodic inspection — visiting the site at appropriate intervals to check that the works are proceeding in accordance with the contract documents, not full-time supervision of every operation. Understanding this distinction, and knowing what to expect from site visits, helps homeowners use their architect's construction-stage services effectively.

Inspection vs Supervision

The distinction between inspection and supervision is important:

• Inspection: Periodic visits to assess the progress and quality of the works, to check compliance with the contract drawings and specification, and to identify issues requiring instruction or correction. The architect does not continuously watch the contractor's operations but exercises professional judgement about the frequency and content of inspections appropriate to the stage of the project.
• Supervision: Continuous oversight of the contractor's operations, implying responsibility for the way in which the works are executed. This is the contractor's own responsibility under the building contract — the contractor controls how and when the works are carried out.

The RIBA's standard appointment agreements use the word "inspection" deliberately to describe the architect's construction-stage visit role. An architect who contracts to inspect is not taking responsibility for the contractor's methods of working or for continuous quality control on the site — they are providing periodic professional assessment against the contract documents.

How Often Should the Architect Visit?

The appropriate frequency of site visits depends on the stage of the project, the complexity of the works, and whether there are items that require inspection before they are concealed. General guidance:

• Substructure stage (foundations, drainage, ground slab): Frequent visits — foundation depths, drain routes and levels are critical and must be checked before being covered over. Typically weekly or more frequently during this stage.
• Structural frame and walls (above ground): Regular visits as work proceeds — checking structural elements, wall ties, lintel positions, and window/door openings against the contract drawings. Typically weekly.
• Roof structure and waterproofing: Visits at critical stages — checking structure, insulation, membrane installation and drainage. Key inspections before roof is sealed.
• First fix services (electrical, plumbing, heating): Inspections at first fix stage before services are covered with plasterwork — the route of pipes and cables, position of outlets, and adequacy of service runs.
• Plasterwork and internal finishes: Inspections to check finish quality, level surfaces, and compliance with specification before decoration begins.
• Second fix and decoration: Visits to check quality of finishes, joinery, fixtures and fittings as they are installed.
• Snagging and completion: A thorough pre-completion inspection to compile the snagging list before the Practical Completion Certificate is issued.

Pre-Concealment Inspections

The most critical category of site inspections are those that must occur before work is covered up — because once covered, problems are very expensive to remedy. Key pre-concealment inspections include:

• Foundation depth and bearing capacity (before pour)
• Drainage falls and levels (before backfill)
• Party wall works (before closing up)
• Structural steelwork connections and fire protection (before encasing)
• First fix electrical and plumbing routes (before plastering)
• Waterproofing membranes (before slab pour or final cover)

The architect should programme these critical inspections in the project programme and alert the contractor to give adequate advance notice before work is concealed at these stages.

What the Architect Checks

During a site inspection, the architect compares what is being built against:

• The contract drawings and specification
• Any variation instructions issued during the course of the project
• Building Regulations requirements and the approved inspector's notes
• The structural engineer's drawings and notes
• Manufacturer's installation requirements for products specified in the spec

Site Visit Reports

Good practice requires the architect to issue a written site visit report after each inspection — recording the date, who was present, the stage of the works, observations, any non-compliances noted, and any instructions issued. Site visit reports provide a contemporaneous record of the project's progress that is invaluable if disputes arise later about what was built, when it was inspected, and what was agreed.

What Homeowners Should Do

Homeowners are entitled to attend site at any time with appropriate safety precautions. To get the most from architect site visits:

• Ask to be informed of each visit date so you can attend if you wish
• Review site visit reports and raise any questions promptly
• Use the pre-completion inspection as a combined walkthrough with the architect to discuss the snagging list
• If you have specific concerns between visits, contact the architect promptly — do not wait for the next scheduled visit

Conclusion

Architect site inspections are a professional service that protects the quality and integrity of a building project. They are not a substitute for the contractor's own quality control — that is the contractor's contractual responsibility — but they provide an independent expert eye that catches problems before they become expensive. For north London residential projects involving specialist construction in conservation areas, listed buildings, or complex basement and structural works, an architect who takes the inspection role seriously is one of the most important safeguards available to the homeowner.