You can check most of your house yourself in an afternoon. What matters is knowing which signs are cosmetic and which mean you should stop and call a structural engineer. This checklist walks you through both.
What the 24–28 September rains did
The late-monsoon rains of 24–28 September 2026 hit Nepal hard. Early counts reported 285 landslides and 15 deaths. Later official figures from the National Disaster Risk Reduction and Management Authority (NDRRMA), as reported by national and international media, rose to 27 deaths and 4 missing, with around 304 landslides and hundreds of houses destroyed, damaged or flooded.
The Kathmandu Valley was not spared. On 28 September, a two-and-a-half-storey house in Dhapakhel, Lalitpur, slid into a river after a landslide that had started the previous day. The family had already been evacuated. Watch for that pattern: ground movement over a day or more before failure.
Safety first: If you see active ground movement, cracks widening by the hour, doors suddenly jamming, or hear cracking sounds, leave the building and call 100 (Police) or your ward office.
How to inspect your house
Take a torch, your phone camera, a measuring tape, a coin and a pencil. Work from outside to inside, and from top to bottom.
- Photograph each crack with a coin beside it for scale.
- Mark both ends of the crack with a pencil and write the date.
- Recheck after two weeks. If the crack has grown past your marks, the building is still moving.
Cracks: cosmetic or structural?
Engineers commonly use the following guideline, which sorts cracks by width. Use it as a guide, not a diagnosis.
| Crack width | Category | What to do |
|---|---|---|
| Less than 0.1 mm (hairline) | Negligible | Cosmetic |
| Up to 1 mm | Very slight | Fill when repainting; monitor |
| 1–5 mm | Slight | Monitor; get advice if it grows |
| 5–15 mm | Moderate | Call an engineer |
| More than 15 mm | Severe | Call an engineer urgently; consider moving out |
The direction of a crack matters too
- Fine vertical or "map" cracks in plaster: Usually shrinkage. Cosmetic.
- Horizontal crack where brick meets a concrete beam or column: Common in RCC frame houses and usually non-structural if it is stable.
- Diagonal or stair-step cracks from door and window corners: Possible settlement. Call an engineer if wider than 1–2 mm or growing.
- Any crack in a column, beam or slab, exposed or rusting rebar, or concrete spalling: Red flag. Call an engineer.
- Cracks that are wider at the top than the bottom (or the reverse): A sign of rotation from foundation movement. Call an engineer.
Damp, seepage and efflorescence
| Sign | Likely cause | Verdict |
|---|---|---|
| Damp at the base of walls up to about 1 m | Rising damp or a failed damp-proof course | Repair; engineer if it persists |
| Ceiling stain under the terrace or a bathroom | Failed waterproofing or a plumbing leak | Repair; urgent if near wiring |
| White powder on walls (efflorescence) | Salts carried out by moisture | Cosmetic symptom; find the water source |
| Rust stains along a slab or beam | Corroding reinforcement | Call an engineer |
| Water coming through basement walls | Groundwater pressure | Call an engineer |
Let walls dry out through Kartik before you repaint. Paint over damp plaster will peel and trap moisture.
Roof, drainage and foundation
- Clear terrace outlets and downpipes, and note any ponding that lasts more than a day.
- Check the roof screed, parapet walls and the gaps around water tank and solar frames for cracks.
- Make sure downpipes discharge away from the foundation, not against it.
- Look for soil washed out from around the plinth.
Signs of settlement: doors and windows that stick, gaps opening between the apron and the wall, sloping floors, and cracks in steps or the compound wall that line up with cracks in the house. Any combination of these means you should call an engineer.
Retaining walls and slopes: the highest risk
If your house sits on or below a slope, or has a retaining wall, check carefully for:
- Walls that bulge or lean, or stones that have been pushed out
- Weep holes that are blocked or missing
- New cracks in the ground above the wall or further uphill
- Trees, electricity poles or fences that have started to tilt
- New springs or muddy seepage at the bottom of the slope
If you see any of these, call an engineer immediately and inform your ward office.
Electrical safety after flooding
- Keep the main switch off until a licensed electrician has checked the installation.
- Never touch switches or appliances while standing on a wet floor.
- Replace sockets, distribution boards and appliances that were under water.
- Have the earthing tested .
Your triage checklist
Probably cosmetic
- Hairline cracks under 1 mm that are not growing
- Efflorescence without any cracking
Monitor for 2–4 weeks
- Masonry cracks between 1 and 5 mm
- Cracks where walls meet beams or columns
- Damp patches that keep coming back
Call an engineer
- Any crack wider than 5 mm, or any crack that is growing
- Any crack in a column, beam or slab, or visible rusted rebar
- Diagonal cracks from openings together with sticking doors
- A bulging retaining wall or cracks in the ground uphill
Leave the building and call 100
- Active ground movement or cracks widening quickly
Frequently Asked Questions
Are hairline cracks after the monsoon dangerous?
Usually not. Cracks under about 1 mm in plaster that are not growing are typically caused by shrinkage. Mark them and recheck after two weeks.
Which cracks need a structural engineer?
Cracks wider than 5 mm, cracks that are growing, diagonal cracks from doors and windows, and any crack in a column, beam or slab.
What is the white powder on my walls?
It is efflorescence: salts left behind as moisture evaporates. It is not structural, but it tells you water is getting into the wall.
How do I know if my retaining wall is at risk?
Look for bulging or leaning, blocked weep holes, cracks in the ground above the wall, and seepage at its base.
Can I switch the power back on after water entered my house?
Not until a licensed electrician has checked the wiring, the distribution board and the earthing.
When should I repair waterproofing?
Once the surfaces have dried out, usually in the dry months after Dashain.
Get a professional inspection
If your self-check put anything in the "call an engineer" column, Ajira Builders can send a civil engineer to inspect your house. You will get a written report that separates cosmetic repairs from structural ones, plus an independent check on any repair quote you receive.
Sources
- The Landslide Blog (Eos): Nepal rainfall, September 2026
- Kathmandu Post: Relentless rain triggers floods, landslides across Nepal
- The Tribune (PTI): Nepal rain fury, 27 killed, 4 missing
- Ratopati: Landslide sweeps house into river in Dhapakhel, Lalitpur
- The Himalayan Times: House collapses in Dhapakhel landslide
- BRE Digest 251 (Revised 1995): Assessment of damage in low-rise buildings