When Do Building Drawings Need an Engineer in Trinidad & Tobago?

Architectural design and structural engineering

The two are related but answer different questions:

On many projects the two overlap: the building-plan requirements published by Municipal Corporations include structural information such as a foundation plan showing footings, piles, columns and beams, and floor and roof framing plans.

Is there a rule for when an engineer is needed?

We couldn't find any official source that sets a simple threshold — a number of storeys, a floor area or a span — above which a house must have engineering drawings. What the official material does say is:

• The DevelopTT planning permission checklist asks for section drawings showing piers, columns, footings, foundation walls and supporting beams, and says that engineering drawings must be submitted for engineering operations.
• DevelopTT lists structural design approval from the Ministry of Works' Construction Division among the approvals a development may need, without setting out which projects require it.
• Under the Municipal Corporations Act, a new building must not be occupied until the Corporation's engineer certifies in writing that it complies.

The Trinidad and Tobago Bureau of Standards publishes TTS 599:2006, a guide to the design and construction of small buildings, which it lists as a voluntary standard.

In practice, then, whether your project needs engineering input depends on the structure you're building and on what the reviewing authorities ask for when they assess it.

Situations where engineering input is often needed

This is professional guidance rather than a legal list, and it isn't exhaustive. Engineering input is commonly needed, or requested during review, where a design involves:

• Two or more storeys, suspended concrete slabs, or heavy roof loads
• Large open spans, or columns and beams carrying significant loads
• Structural steel — frames, portal-frame buildings, mezzanines, large canopies
• Retaining walls, or building on a steep or unstable slope
• Poor or uncertain ground, or foundations such as piles
• Commercial, industrial or public buildings
• Alterations that remove or change load-bearing walls, or add a floor to an existing building

What engineering work usually involves

1. CalculationsWorking out the loads on the structure and sizing its members to carry them.
2. Structural drawingsFoundation plans, framing plans, and the sizes and reinforcement of structural elements.
3. DetailsHow the parts connect — beam-to-column joints, steel connections, reinforcement laps and anchorage.
4. Review and certificationA registered engineer signs or stamps the engineering documents they are responsible for.

What engineering stamping means

The Engineering Profession Act (Chap. 90:01) established the Board of Engineering of Trinidad and Tobago, which registers engineers. The Act prohibits anyone who is not a registered engineer from signing or stamping plans, drawings, designs or specifications as though they were acting as one. The Board publishes the register of engineers.

A stamp is a professional declaring responsibility for the engineering in those documents. That's why it matters who prepared them.

Why existing drawings can't simply be "stamped"

People sometimes have a full set of drawings — from a previous designer, an online plan or an older project — and look for an engineer to stamp them. It usually isn't that simple.

The code of ethics in the Engineering Profession Act says a registered engineer shall sign or stamp only plans, specifications and reports actually prepared by them or under their direct professional supervision, and only those that reflect proper regard for public safety and health.

So an engineer asked to stamp existing drawings will generally need to review the design properly, check or redo the calculations, and may require changes before they can take responsibility for it. Sometimes the structure needs to be redesigned. It's worth planning for that time and cost rather than assuming a stamp is a formality.