BuildSafe Caribbean

Building Problem Triage Guide

How to tell whether a crack needs an engineer today, needs one soon, or just needs watching.

Written for building owners in Trinidad and Tobago.

Stop. Get out first if any of these are true.

A column or beam is cracked, or concrete has broken away and you can see the steel.
A crack in a column runs diagonally, or in an X.
A floor or roof visibly sags, or a wall is visibly leaning.
A crack is getting wider while you watch it, over hours or a few days.
Doors and windows have suddenly started jamming and new cracks appeared at the same time.
The ground beside or under the building has opened, slumped or moved.
Any of the above after an earthquake, a heavy storm, or digging next door.

Get everyone out. Do not go back in for belongings. Do not try to prop it yourself, because a bad prop can move the load somewhere worse. Call emergency services, then call an engineer.

If none of those apply, you have time. Use it properly. What follows takes about twenty minutes and will save you money whoever you end up calling.

1. Measure it and date it

This is the most valuable thing you can do, it costs nothing, and almost nobody does it. A crack that is not moving is a completely different problem from one that is, and the only way to know which you have is to measure the same crack twice.

Measure the width at the widest point. A credit card is about 0.8 mm thick, which is a useful thing to compare against when you have no ruler.
Mark both ends with a pencil line across the crack, and write the date beside it. Pencil, not marker, so you are not defacing the wall.
Photograph it with a ruler held against it and the date visible.
Check again at four weeks, then at twelve. Note whether the ends have passed your pencil marks and whether the width has changed.

If you do nothing else in this guide, do this. An engineer who arrives to two dated measurements taken eight weeks apart can tell you far more, far faster, than one who arrives to a crack with no history.

Rough width bands

Width	What it usually means
Under 1 mm	Usually cosmetic. Worth marking and watching, not worth panicking over.
1–5 mm	Worth a proper look, particularly if it is growing or diagonal.
5–15 mm	Get it assessed. Something has moved by an amount that needs explaining.
Over 15 mm	Get it assessed now, and re-read the red flags above.

These bands are indicative only, and width alone never decides it. A 2 mm crack through a column matters more than a 10 mm crack in a garden wall. Where the crack is matters more than how wide it is.

2. Read what kind of crack it is

You are not diagnosing it. You are gathering the things an engineer will ask you.

What you see	What it tends to suggest
Stair-stepping along the mortar joints	Movement in blockwork. Common with settlement. Take it seriously if it is growing.
Straight through the blocks themselves	More force involved than a joint crack. Worth a professional look.
Fine, map-like cracking in the render only	Usually shrinkage in the plaster. Normally cosmetic.
Diagonal, from the corner of a window or door	Stress concentrating at an opening. Very common, and worth measuring.
Horizontal, around mid-height of a wall	Can mean sideways pressure on the wall. Do not ignore this one.
Vertical, where two materials or two build stages meet	Often thermal movement or shrinkage at a junction.
Wider at one end than the other	Tells you which direction things moved. Photograph both ends.
Rust stains, concrete flaking off in sheets	Steel inside is corroding and expanding. Gets worse, never better, on its own.

3. Go and find the water

A large share of building problems here trace back to water, and the crack is the symptom rather than the fault. Repairing a crack while the cause is still running is money thrown away. Before you pay for any repair, walk the outside of the building and look at:

Downpipes. Where does the water actually land? If it discharges beside the foundation, it is soaking the ground the building sits on.
Gutters. Blocked, overflowing, or sagging.
The ground against the wall. Does water pond there after rain? Does the ground fall away from the building, or towards it?
Plumbing. A slow leak under a slab can undermine a foundation for years before anything shows on the wall.
Sloping ground. What is happening uphill of you, and where does that water go in the wet season?
Salt air, if you are near the coast. It drives the rust staining and flaking concrete described above.

Photograph whatever you find. Also photograph anything that changed recently: building next door, a new extension, a large tree planted, or a large tree removed.

4. Work out who you actually need

Most people call a contractor because a contractor is who they know. Sometimes that is right. Often it is the wrong first call, and it is expensive to find that out afterwards.

Who	What they are for
Contractor or mason	Building and repairing. They will fix what you point at. Diagnosing why it happened is not what they are trained for, and asking them to do it is not fair to them.
Structural engineer	Whether the structure is safe, what is carrying the load, and what the crack means. This is who you want when a crack might be structural.
Geotechnical engineer	The ground itself. Foundations, settlement, fill, slopes. For when the building is sound but what it sits on is not.
Quantity surveyor	What the work should cost, and whether a quote is reasonable.
Insurance adjuster	Works for the insurer, not for you. Their job is to establish what the policy covers. That is legitimate, and it is not the same as your interest.

Before you pay anyone

Ask whether they are registered, and with which board.
Get the scope in writing before work starts, including what happens if the cause turns out to be different from what everyone assumed.
Be wary of anyone who quotes a repair before diagnosing the cause.
Where you can, keep the diagnosis separate from the repair. Someone who earns from the repair has an interest in what the diagnosis says. That is not an accusation of dishonesty, it is just a reason to separate the two.

5. What to photograph before anyone visits

Every one of these saves time on site, and time on site is what you are paying for.

The whole wall or elevation, so the crack can be located on the building.
The crack close up, with a ruler in the shot.
Both ends of the crack.
The same wall from inside and outside, if you can get to both.
The ground, gutters and downpipes nearby.
Your dated pencil marks from step 1, on both visits.

What this guide is not

This is general guidance for building owners. It is not an engineering assessment of your building, and it is not advice about your specific situation. Nobody can responsibly diagnose a particular building from a guide, or from photographs alone, without seeing it.

What this guide can do is help you tell urgent from not urgent, stop you paying to repair a symptom while the cause keeps running, and let you have a much better conversation with whoever you call. If you are unsure, treat it as serious and get it looked at.

If you want an engineer to look at it, tell us about the property and you'll get a fixed-scope quote before any work starts.

Ask for a Quote →

Eng. Jackie John, MEng, BSc, R.Eng., MAPETT
Registered Engineer (Civil), Board of Engineering of Trinidad and Tobago — Registration No. 04-744
Jameri Consultants Limited, trading as BuildSafe Caribbean
buildsafecaribbean.com

You are reading this because you took part in the BuildSafe Caribbean research survey. The short summary of what the research finds will follow once there is enough of it to say something honest.

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