Site supervision is the day-to-day checking that construction matches the drawings, specifications and safety rules. On a typical Tanzanian project the contractor's site engineer supervises the workers, while the client's clerk of works and consultants (architect, structural engineer, services engineers) inspect on the client's behalf. Good supervisors check setting out, excavations, reinforcement, concrete, walls, roofing, services and finishes before each stage is covered, keep a site diary and inspection records, and raise problems early. Without supervision, small mistakes get built in and become expensive defects.
Who supervises what?
| Role | Works for | Main job |
|---|---|---|
| Site engineer or site agent | Contractor | Runs the work daily, checks workmanship, plans tomorrow |
| Foreman | Contractor | Leads a trade or gang |
| Clerk of works | Client | Full-time or regular inspector on the client's side |
| Resident engineer | Client (on larger projects) | Senior engineer based on site |
| Architect and engineers | Client | Periodic inspections and approvals |
| Safety officer | Contractor | Site safety and compliance |
On small projects the client's side may be just the architect visiting weekly. On larger or public projects a full-time clerk of works or resident engineer is normal. See who does what on a construction project.
What does a clerk of works check?
Before work starts
- Drawings are the latest revision and approved.
- Setting out matches the site plan and building lines. See setting out.
- Materials on site match the specification.
Foundations and structure
- Excavation depth and bearing soil.
- Blinding, reinforcement sizes, spacing, cover and laps.
- Formwork lines, levels and propping.
- Concrete slump, placing, compaction and cubes. See cube testing.
- Curing and striking times.
Walls and roof
- Block quality, mortar, plumb and bonding. See blockwork defects.
- Lintels, ring beams and DPC.
- Roof truss fixing, sheet laps and flashing.
Services and finishes
- Conduits and pipes before walls are plastered.
- Pressure tests before pipes are covered.
- Plaster thickness, tile levels, paint coats.
On civil works and roads
Supervision on roads and drainage focuses on layer thickness, moisture and compaction of each layer, levels and falls, culvert bedding and joints, and asphalt or surface dressing quality. See road construction layers and culverts and road drainage.
Records a supervisor keeps
- Daily site diary: weather, labour, plant, work done, deliveries, visitors.
- Inspection forms signed at each hold point.
- Test results.
- Instructions given and requests for information.
- Photos with dates.
- Weekly or monthly reports to the client.
See how to monitor construction progress.
Safety is part of supervision
Supervisors stop unsafe work: missing edge protection, unsafe scaffolds, deep trenches without support, workers without protective gear. A good site is a tidy site. See construction site safety in Tanzania.
Signs a site is poorly supervised
- No engineer on site during concrete pours.
- Reinforcement covered before inspection.
- Workers unsure which drawing to follow.
- No site diary or records.
- Materials dumped in the open and damaged.
- The same defects appearing again and again.
How much supervision does a project need?
| Project | Typical supervision |
|---|---|
| Small house | Architect or engineer visits at key stages, plus an owner's representative |
| Larger house or small commercial | Weekly visits plus inspections at hold points |
| School, office, bank, clinic | Clerk of works on site, regular consultant visits |
| Large building or road | Resident engineer and team, full-time |
A day for a clerk of works
A typical day on a building project might run like this:
- Morning: walk the site before work starts, note weather and labour, check safety and that the right drawings are in use.
- Mid-morning: inspect work ready for approval, such as reinforcement for a beam, and sign off or list corrections.
- Midday: check deliveries against the specification and reject anything that does not comply.
- Afternoon: watch critical activities such as a concrete pour, take cubes, record any issues.
- End of day: update the site diary, file photos, note instructions given and questions for the designers.
Weekly, the clerk of works joins site meetings and reports to the client or consultants. The value of the role is being there when things happen, not hearing about them later.
How a supervisor raises a problem
- Point it out on site to the contractor's site engineer straight away.
- Record it in writing with a photo and location.
- Agree the correction and when it will be done.
- Re-inspect and sign off once fixed.
- If it is not fixed, raise it at the site meeting and with the consultant.
Firm but fair supervision earns respect. Supervisors who shout but never write anything down rarely get problems fixed.
Who makes a good clerk of works?
Usually a technician or engineer with several years of site experience across trades. Knowing what good work looks like matters more than formal titles, but they should be able to read structural and services drawings and understand the specification.
Frequently asked questions
What is a clerk of works?
An inspector employed for the client to check that construction follows the drawings and specifications, and to keep records.
Is the clerk of works the same as the site engineer?
No. The site engineer works for the contractor and runs the work. The clerk of works checks it for the client.
Who pays for site supervision?
The client pays for its own supervisors and consultants. The contractor pays for its site team.
Can I supervise my own building?
You can watch progress, but technical checks such as reinforcement and concrete need a qualified engineer. See fundi or registered contractor.
What records should a clerk of works keep?
A daily site diary, signed inspection forms, test results, dated photos, a log of instructions and requests for information, and regular reports to the client.
Can one supervisor cover several sites?
For small projects, yes, with visits planned around key stages. Larger projects need someone on site every working day.
When must the engineer be on site?
At every hold point: excavations before concrete, reinforcement before each pour, and any change to the structure. The contract or inspection plan should list these.
Want a well-supervised project?
Every Vika Construction site has a qualified site engineer and a daily inspection routine. See our quality approach or contact us.
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