⚠ This guide has not yet been reviewed by a licensed engineer.
It is a reordering of official public guidance — ANIH, CENAPRED, BRE Digest 251, the EMS-98 scale — each one cited in the sources. It is not a technical determination and it does not replace an engineer.
None of its three outcomes says your building is safe; the mildest one, MONITOR, means “keep watching this”, never “it’s fine”. When in doubt, go up a level.
Are you a structural engineer and you see an error? Correcting it matters more than publishing it: this guide is released under a free licence (CC BY-SA 4.0) so that it can be corrected, printed and handed around without asking anyone’s permission.
About this English version. This is a translation of a Spanish-first guide written for Venezuela. The Spanish original is the authoritative text — if the two ever disagree, the Spanish one is correct. The emergency numbers and the inspection route in section 8 are Venezuelan; if you are somewhere else, use your own country’s numbers and your own country’s engineers. Local terms are kept in brackets so you can use them on the phone with family: cabilla = rebar, friso = plaster, viga = beam, columna = column.
First, and it matters more than anything else here:
No photo and no web page can tell you that your building is safe. Not this one either. Only a licensed engineer (one registered with the Colegio de Ingenieros de Venezuela) standing there, looking at the structure, can say that.
That is why this guide has only three exits, and none of them says “it’s fine”: MONITOR · PROFESSIONAL INSPECTION · GET OUT NOW.
If at any step you don’t know which case is yours, or the doubt stays with you: go up a level. Anything you don’t understand is treated as more serious, never less. Erring upward costs you an inspection; erring downward costs a life.
1. Signs that are not up for discussion: GET OUT NOW
Before you measure anything or compare any drawing: if you see any of these signs, stop reading inside the house. Get out, move people away from the building, and call emergency services.
Leave the building right now if you see…Level 3 of 3
- Exposed rebar (cabilla) — the steel bars of a column, beam or roof slab are uncovered, especially if they are bent or splayed open like a banana peel.
- Crushed or crumbling concrete at the end of a column, or where a column meets a beam (the “joint”, nodo).
- The building or a wall is leaning, visibly out of plumb, or a wall is bulging outward.
- A roof or floor slab hanging down, sagging, or any part of the structure that has already fallen.
- A thick X-shaped crack in a column or a load-bearing wall, with pieces of plaster or block broken loose.
- You can see through a crack to the other side of the wall, or fit a whole finger into it.
- Noises: the structure creaks, cracks or groans while you are inside.
- A smell of gas, or loose electrical cables that are wet: get out, and do not switch anything on or off inside.
What you do: you leave, you do not go back in “just for a second” to get things, you warn the neighbours on the floors above and below, and you call the numbers in section 8. Afterwards you request a professional inspection.
These signs are taken from the description of serious structural damage in post-earthquake assessment guidance (ANIH, CENAPRED) and correspond to the highest damage grades of the EMS-98 scale (D4–D5): serious failure of walls, crushing of concrete and fracture of rebar, leaning or collapse of columns. See sources.
2. The only three answers
Everything that follows in this guide ends in one of these three. There is no fourth one that says “safe”, “habitable” or “nothing to worry about”. A web page cannot give you that; an engineer gives it to you.
MONITORLevel 1 of 3
It means exactly this: in what you are looking at right now, no sign of danger is visible. It does not mean the house is sound. It is not a certificate of anything.
What you do: the pencil-and-date protocol (section 6). You mark the ends of the crack with a pencil, you write the date on it, and you check it after every aftershock. If it grows, go up a level.
PROFESSIONAL INSPECTIONLevel 2 of 3
There is something a phone and a guide cannot settle: the crack is in an element that carries weight, or it has a shape that speaks of structural stress, or it simply cannot be known from a photograph.
What you do: you request the inspection (section 8), you document it with photos before cleaning up, and in the meantime you treat the area with care: do not sleep under a roof or a wall whose damage is in doubt.
GET OUT NOWLevel 3 of 3
There is a risk of something falling on somebody, today, with the next aftershock.
What you do: what section 1 says.
The tie-break rule. If you are torn between two, you take the more serious one. If the photo is blurry, dark, too close up, or you cannot tell which element it is, that is not “monitor”: that is professional inspection. Not being able to see the danger does not mean it isn’t there.
3. Before you clean up: take the photos
This is done before you sweep, patch, plaster over or throw out rubble. If you clean up first, the damage can no longer be verified, and that evidence is what the inspection, the insurance claim, and any aid or reconstruction programme will depend on later. It is the same requirement that official damage-certification systems ask for in other countries, and it costs nothing.
Photo protocol — 4 steps
- All four faces of the building, complete. Step back until the whole building fits in frame, and take one photo of each side: front, back and both sides. Even a side with no damage.
- A far shot and a close shot of every piece of damage. First a wide one showing where the crack is within the wall or the room (so it is clear which element it is), and then the close-up of the detail. A photo taken right up against the wall, on its own, is no use: nobody can tell whether that is a column or a partition.
- Put something in for scale. A coin, a ruler, an ID card (cédula), a pen, your own hand next to the crack. Without that, nobody can know whether that line is 1 mm or 2 cm.
- Do not destroy the date. Let the phone save the time automatically, do not change the date on the device, and do not send the photos only over WhatsApp — compression strips the data. Keep the original files, and if you can, make a copy on another phone, a memory card, or in the cloud.
Also useful: write down on paper or in a phone note the date, the time and the earthquake or aftershock after which each crack appeared or grew. That timeline is worth as much as the photo.
4. The decision tree: four questions, in this order
This is the decision tree used by guidance written for ordinary people (ANIH, CENAPRED). You answer it by looking, with no instruments. The questions are in this order on purpose: where the crack is matters more than how wide it is.
Question 1 — Where is the crack?
There are two different worlds:
- In the plaster only (friso — the finish coat, the fine layer that gets painted). Plaster is make-up: it cracks and it carries nothing. You recognise it because the crack is shallow, you can sometimes see the colour of the block underneath, and it follows the pattern of the surface rather than a structural line.
- In a structural element: column, beam, load-bearing wall, roof slab or floor slab, and the joints between them. These are the bones. Any crack in a bone is, at minimum, professional inspection. It is never “monitor” on its own.
And if you don’t know which of the two it is? Plenty of people cannot tell a column from a block wall with plaster over it — that is normal, they are painted the same. Don’t know = professional inspection. Do not guess downward.
Question 2 — What shape is it?
The shape of the crack tells you what happened to the material: a crack opens perpendicular to the force that pulled it. That is why the drawing says more than the width. Compare your crack with the six patterns in section 5 and take the one it most resembles. If it resembles two, take the more serious one.
Question 3 — How wide is it?
Width comes after where and what shape. It works as supporting evidence, not as a verdict. The most widely used reference in the world for classifying crack width in low-rise buildings is BRE Digest 251 (United Kingdom), which groups them like this:
| Width | What it is called | What it implies here |
|---|---|---|
| Less than 1 mm | Very slight / hairline | In the plaster: normally monitor. In a structural element: inspection all the same. |
| 1 to 5 mm | Slight | Still “aesthetic” per the BRE, but if it is diagonal, stepped, or in a bone: inspection. |
| 5 to 15 mm (or several over 3 mm) | Moderate | Professional inspection. This is the threshold the reference itself sets for calling in a specialist. |
| 15 to 25 mm | Severe | Urgent professional inspection, and treat the area as dangerous in the meantime. |
| More than 25 mm | Very severe | Get out now. At this level the reference speaks of a risk of partial collapse. |
A warning that comes from the standard itself: the BRE says explicitly that width on its own diagnoses nothing. What weighs more is the pattern, the direction, the location, how many cracks there are, and above all whether the crack is still moving. On top of that, this table was written for ground-settlement damage in low-rise houses, not for earthquake damage. Use it as support, not as a sentence.
Question 4 — Is it alive? (this is the one that matters most)
A crack that has stopped moving and a crack that grows with every aftershock are completely different things, even if they measure the same. Go up a level if any of these is true:
- It grew, lengthened or opened after an aftershock.
- A new one appeared where there was none.
- It is shedding dust or bits of material, today.
- The doors or windows have stopped closing, or they rub where they did not rub before.
- The floor feels uneven, or a marble rolls to one side on its own.
- You can hear noises from the structure.
These signs only raise the level, never lower it. A fine crack in the plaster that grew after the aftershock is no longer “monitor”: it is inspection.
5. The six patterns
Find which one most resembles yours. Each drawing says what is happening to the material and what level it leads to.
1. Fine hairline cracks in the plaster
What it is: the finish coat has cracked. Usually lines under 1 mm, short, branching, scattered with no clear direction. Sometimes you can see the block or the mortar underneath.
What it means: the make-up cracked, not the bone — in what this wall shows. MONITOR. Note carefully: this does not mean the house is fine. It means no sign of danger is visible here. If that same hairline grew after an aftershock, or it sits on a column, go up to inspection.
2. Vertical crack at the wall–column junction
What it is: a straight line, top to bottom, exactly where the wall meets the column (or the beam). The wall and the structure are separating: they are different materials, stuck together, and they moved differently.
What it means: here the location rules, not the width. If the separation is only between a partition and its frame, it tends to be less serious; but if the vertical crack is inside the column itself, or light or air comes through the gap, or the wall has come loose and can be pushed: PROFESSIONAL INSPECTION. A wall that has come loose from its frame can topple in the next aftershock.
3. Diagonal cracks, and the X
What it is: the classic earthquake signature. The wall was sheared from side to side. The X appears because the shaking pushes first one way and then the other: each push leaves its own diagonal.
What it means: PROFESSIONAL INSPECTION at minimum, even if it is thin, even if it is in a partition. And it becomes GET OUT NOW if the X is wide, if it is in a column or a load-bearing wall, or if there are pieces broken loose. Practical detail: shear cracks do not close back up when the shaking stops — if you can still see it open with everything still, that is shear, not simple movement.
4. Stepped crack along the mortar joints
What it is: the crack climbs in a staircase, alternating vertical and horizontal runs, always through the mortar between the blocks, never splitting the block. It travels where the material is weakest: mortar is far weaker than the block.
What it means: this same drawing has two different causes — ground settlement (the house sank on one side) or earthquake shear. You tell them apart like this: the settlement one opens wider towards one corner and usually comes with the house leaning or the floor uneven; the earthquake one appears in symmetrical pairs, forming the X of pattern 3. In either case: PROFESSIONAL INSPECTION.
And a separate rule: if the crack splits the blocks through the middle instead of travelling along the mortar, it is more serious, not less — it means the strong material gave way, not just the glue.
5. Horizontal sliding along the mortar joint
What it is: a long horizontal crack following a single joint, as if the wall had split into two halves that slid over one another. It also appears when the wall was pushed face-on rather than sideways.
What it means: it is among the most dangerous and among the least recognised, because it looks “tidy”. PROFESSIONAL INSPECTION always. And it becomes GET OUT NOW if the wall is also bulging outward: stand at one end and sight along the wall, the way you would sight down the edge of a plank. A wall that bulges and leaves its own plane topples whole, and that is one of the main causes of death in an earthquake.
6. Crushing and exposed rebar at the beam–column joint
What it is: the “joint” (nodo) is where a beam and a column cross, and it is the point that carries more stress than anywhere else in the building. When it fails, it looks like this: the outer concrete breaks away, the vertical rebars and the ties (the hoops that bind them) are left exposed, and the rebars bend or splay open.
What it means: GET OUT NOW. No discussion, no measuring the width of anything. This damage advances in order — first the cover falls off, then the ties burst, then the rebar buckles, and finally the concrete inside is crushed and the column stops holding the weight. This kind of failure is brittle: it gives no warning, it does not bend gradually, it gives way all at once. And if the damage is on the ground floor (the parking level or the shopfronts, which tends to be the most open one), get everyone out of the whole building, not just that floor.
6. The pencil-and-date protocol
This is what “monitor” means. It is free, it takes two minutes, and it turns a crack into a measuring instrument.
- Mark both ends. With a pencil (not a permanent marker — you won’t be able to see the movement afterwards), draw a short tick across the crack exactly where it ends, at each end.
- Write the date next to each mark. Day and month. If you know the time of the earthquake or the aftershock, put that too.
- Mark the width at one point: two small ticks facing each other on either side of the crack, and the date. That way you can see later whether it opened, not just whether it lengthened.
- Take the photo of the crack with its marks and a coin beside it (section 3).
- Check after every aftershock, and if there are no aftershocks, once a week for the first month.
If the crack has passed its marks, opened up, or new ones have appeared: go up to PROFESSIONAL INSPECTION. A crack that moves is a live crack, and that matters more than its size.
7. What not to do
- Do not patch or plaster over the crack yet. It is the evidence. Covering it fixes nothing, hides whether it is growing, and can cost you the inspection or the claim.
- Do not knock down or chip away at walls to “relieve” anything — you may be removing something that is carrying weight.
- Do not go in to fetch things from a building you have already called “get out now”, not even quickly. Aftershocks arrive without warning.
- Do not sleep or put the bed under a wall, a roof or a staircase whose damage is in doubt.
- Do not trust “it looks the same as yesterday” if you did not mark it with a pencil. Nobody remembers a millimetre.
- Do not pay in advance to anyone who turns up offering urgent inspections or repairs: see the fraud warning below.
8. Where to turn
Professional structural inspection
- SismoAyuda VE — sismoayudave.com — post-earthquake structural assessment platform. You fill in a form with the building’s details and upload photos or video of the damage following the guidance on the page. Volunteer engineers and architects register through the Colegio de Ingenieros.
- Colegio de Ingenieros de Venezuela — civ.net.ve — this is the body that accredits the professionals who carry out these inspections. Look for your state’s branch.
⚠ Beware of fraud. According to the Colegio de Ingenieros, inspections by their certified specialists are free, and the inspector must present credentials and a QR code. If somebody charges you to “certify” your house, rushes you, or will not show credentials: they are not from them. Verify before you let anyone in and before you pay.
Emergencies (Venezuela)
| Emergencies (national) | 911 |
|---|---|
| Civil Protection (national) | 0800‑5588427 · 0800‑2668446 · 0800‑2624368 |
| Civil Protection (Caracas) | 0212‑575‑18‑23 |
| Caracas Fire Brigade | 0212‑542‑02‑43 · 0212‑542‑26‑23 |
| FUNVISIS (seismic information) | 0‑800‑TEMBLOR (0‑800‑836‑2567) · funvisis.gob.ve |
And afterwards
- Socorro — to search for people and animals, report sightings and coordinate help.
- Cimiento — reconstruction guide — for when it is time to repair or rebuild: how to build confined masonry that will hold up in the next earthquake, instead of repeating what failed.
- Drop, cover, hold on — what you do during the earthquake, rather than running for the door. It is the standard recommendation (ShakeOut).
9. Where all of this comes from
This page does not invent criteria: it reorders published guidance so that it can be read on a phone. Every statement comes from here.
- ANIH — Academia Nacional de la Ingeniería y el Hábitat (Venezuela), Boletín no. 61. The decision tree for non-specialists. acading.org.ve — bulletin index.
- CENAPRED — Centro Nacional de Prevención de Desastres (Mexico): forms and instructions for assessment and inspection of housing damage after an earthquake. Housing data-capture form manual (PDF) · gob.mx/cenapred.
- Government of Mexico — “Después de un sismo”: assessment of injuries and damage. sismos.gob.mx.
- BRE Digest 251, Assessment of damage in low-rise buildings (Building Research Establishment, UK; based on Burland, Broms & de Mello, 1977). The width bands in section 4 and the warning that width alone diagnoses nothing come from here. Paid publication: bregroup.com.
- EMS-98 — European Macroseismic Scale 1998 (Grünthal, ed.), damage grades D1 to D5. The description of serious damage in section 1 comes from here. Original English text (PDF) · GFZ.
- ATC-20 — Procedures for Postearthquake Safety Evaluation of Buildings (Applied Technology Council, USA). This is the green / yellow / red placard procedure used by trained assessors. Important: even its own green placard means only “no apparent hazard found at the time of inspection” — it does not certify that the building is sound, and it does not cover later aftershocks. If a professional’s paperwork, on site, is not a safety certificate, a photo on a phone is very much less so. atcouncil.org.
- Colegio de Ingenieros de Venezuela and SismoAyuda VE — the inspection route, and the warning about credentials and free service: civ.net.ve · sismoayudave.com.
- The r/vzla guide by u/teexplicove (2026), the version that went viral and showed that this needed to exist in one place.
And again, because it is the one thing that cannot fail: this guide only raises the level of caution. It never says a building is safe, it never replaces a technical determination, and it is never a reason not to request an inspection. If after reading all of this you are still in doubt: treat it as the highest level that crossed your mind, and call.