What interventoría means
The word appears in almost every public works contract in Colombia. An interventor is a professional or a firm, independent of the contractor, whose job is to verify that the work is built as contracted. That is exactly what a foreign buyer needs on a private project, where no public entity is watching.
John has done this work throughout his career: oversight and control of civil and electrical works, supervision of medium and low voltage electrical networks, and today the coordination of a portfolio of 50 contracts with 43 contractors in a public entity. The method is the same for a single house. What changes is the scale.
Technical and administrative oversight
Technical oversight checks the work itself:
- Is it built according to the drawings and specifications?
- Are the materials and the workmanship acceptable?
- Are the structural, electrical, plumbing and other installations built to the applicable codes?
- Is the progress real, and does it match the schedule?
Administrative oversight checks the contract around the work:
- Is the contract scope being followed?
- Do the payment requests match the progress in place?
- Are changes documented, priced and approved before they are built?
- Are permits, insurance and required documents in order?
What we check, stage by stage
| Stage | What is verified | Evidence you receive |
|---|---|---|
| Before starting | Contract, drawings, permits, budget and schedule are consistent | Review note and a list of open questions |
| Site preparation and foundations | Excavation, levels, foundation dimensions and reinforcement against the drawings | Photos, measurements and a written check |
| Structure | Reinforcement before each concrete pour, formwork, concrete placement and curing | Photos and inspection notes per element |
| Masonry, roofs and envelope | Alignment, waterproofing and connections | Photo report and observations |
| Installations | Electrical, plumbing, drainage and gas installations before they are covered | Photos of installations open, checked against the design |
| Finishes | Quality, tolerances and completeness against the specification | Punch list |
| Handover | Final walkthrough, pending items, as-built drawings, permits and warranties | Handover package |
Some checks can only be done once, at the right moment. Reinforcement can be seen before the concrete covers it, and pipes and cables can be seen before the wall is closed. This is why oversight is most useful when it starts before the foundations.
Code compliance
Ongoing verification is done against the Colombian codes that apply to a house, which include:
- NSR-10, the seismic-resistant construction code.
- RAS, the technical regulation for drinking water and basic sanitation.
- RETIE and NTC 2050 for electrical installations, and RETILAP for lighting.
- NTC 1500, the plumbing code, and the gas regulations when the house has gas.
- The conditions of the building permit issued by the curaduría or the planning office.
For a plain-language introduction, see our guides to NSR-10 and RETIE. Codes and their transition dates change, so the current text is always checked before it is applied to your project.
Reporting
You receive regular progress documentation in photos and video, written reports, and budget-versus-actual variance reports in COP, USD and EUR. The reports are written to be read by an owner, not only by another engineer.
When to hire oversight
- Before the contract with the builder is signed, so scope, schedule and payment milestones can be adjusted.
- Before the foundations are poured, so key elements are checked when they are still visible.
- Before each large payment, if the work is already under way.
- Before the final payment, to make sure that pending items are listed and agreed.
Scope and limits
Oversight verifies. It does not replace the builder’s responsibility, the designer’s responsibility or the licensed professionals who sign the structural, electrical or architectural designs. Legal, architectural and insurance services are provided by licensed, independent professionals from our network. If you need the whole project to be run and coordinated, read about construction project management.