Crack monitoring in London
One visit shows a crack as it is on the day. Monitoring shows whether it is still moving. Our structural engineers fix gauges across the cracks that matter, read them through the seasons and tell you plainly whether the movement is historic, seasonal or ongoing, and what to do next.
2,700+ projectsCompleted by our engineers
Since 2016Based in Chiswick, working across London
Master's-qualifiedEvery inspecting engineer has a master's in structural engineering
£1 millionProfessional indemnity insurance
What crack monitoring tells you that one visit cannot
Many cracks look the same on the day whether they stopped moving thirty years ago or are still opening. A single inspection tells you the likely cause and how serious the damage looks. It cannot always tell you whether the movement has stopped, and that is often the question a lender, an insurer or a buyer's solicitor is really asking.
Much of London is built on shrinkable clay. In dry summers the clay loses water and shrinks, especially near trees, and in wet winters it swells again. Cracks can open and close with the seasons. Readings taken over several months, or over a full year when a certificate is needed, show the difference between a crack that moves with the weather and one that keeps getting wider.
At the end you get a clear answer from a structural engineer: whether the movement is historic, seasonal or ongoing, and what that means for repairs, insurance or a sale.
- HistoricReadings stay steady. The crack can be repaired, and after a year we can issue our certificate.
- SeasonalIt opens in summer and closes in winter. We find the cause, often clay and trees, before repairs.
- OngoingIt keeps getting wider. Further investigation, and often an insurance claim, come before any repair.
Reading a crack monitor: stable, seasonal or still moving
A tell-tale crack monitor is two overlapping plates fixed across the crack, one on each side. One plate carries a millimetre grid. The other is clear, with a red cross. If the crack opens, closes or one side drops, the cross moves across the grid, and we record where it sits at every visit. Choose an example to see what each pattern looks like over a year.
- Crack width
- 3.1 mm
- Since first visit
- 0.1 mm wider
- Up and down
- No change
Stable: the movement is historic
The cross barely moves all year. The crack is old movement that has stopped, so it can be repaired. After a full year of stable readings we can issue our certificate of structural adequacy for the condition of the property.
Seasonal: it moves with the weather
The crack opens in the dry months and closes again in winter, ending the year close to where it started. This is typical of clay soil drying out near trees. We explain the likely cause and what will stop it, such as tree management, before cracks are repaired.
Still moving: the movement is ongoing
Each summer it opens further and winter does not close it, and one side is dropping. The cause needs investigating before any repair, with a structural inspection, drain checks or trial pits, and you may need to tell your insurer.
Illustration only, not readings from a real property. The example crack is 3 mm wide at the first visit; the crack and gauge are drawn about ten times larger than life.
Our crack monitoring on site
Each gauge is fixed across the part of a crack that tells us most, usually its widest point. Different walls need different gauges: screwed or bonded, inside or out, and read by eye, by calliper or from a photograph. At every visit we record the reading and photograph the gauge from the same spot, so any change is easy to see.
When crack monitoring is worth doing
Monitoring is the right next step when the question is whether movement has stopped. These are the situations we are asked about most.
A crack that keeps coming back
It was filled and has opened again, or you can see it getting longer or wider.
Suspected subsidence
Before you decide on a claim, underpinning or major repairs, you want to know if the ground is still moving.
Buying or selling
A lender, valuer or buyer's solicitor wants evidence that past movement has stopped.
Insurance after subsidence
Your insurer wants proof of stability, or the original certificate of structural adequacy is missing.
Checking that repairs worked
After tree work, drain repairs or structural repairs, readings confirm the movement has stopped before redecorating.
Building work next door
A basement, extension or demolition nearby, and you want a record of your cracks before and during the work.
How our crack monitoring works
From your first message to the final readings, this is what happens.
Tell us what you have seen
Send photos of the cracks, when they appeared and what your insurer, lender or buyer has asked for. We recommend a route and send the price in writing before you book.
First visit: inspect and fix the gauges
An engineer inspects the cracking and its likely cause, fixes a gauge across each key crack, and records the starting readings, widths and photos.
Readings through the seasons
We return to read each gauge and photograph it from the same spot. The visits are spread so the readings catch both the dry and the wet months.
Your results and our conclusion
You receive every reading and our conclusion: historic, seasonal or ongoing, and what it means for repairs. After a full year of stable readings, our certificate.
What you receive at the end
- The parts of the building monitored and where each gauge was fixed.
- The date of every visit and every reading taken.
- Photographs of each gauge, taken from the same spot.
- Our opinion on whether the movement is historic, seasonal or ongoing.
- What that means for repairs, and any further investigation needed.
- Our certificate of structural adequacy after a year of stable readings.
Crack monitoring or a one-off crack inspection?
Most people start with an inspection. If the engineer cannot tell from one visit whether the movement has stopped, or someone needs evidence that it has, we recommend monitoring.
| Question | Crack inspection | Crack monitoring |
|---|---|---|
| What it answers | The likely cause, and how serious the damage looks today | Whether the crack is still moving, and how |
| Visits | One | A first visit, then return visits over several months |
| Your answer | Usually within 5 working days | At the end of the monitoring period |
| Price | From £420* for one crack, or £590* for several | From £2,100* for a year, with our certificate |
| Best for | A first answer, buying, or a single crack | Insurers, buyers' solicitors, and decisions on major repairs |
Compare the Specific, General and Comprehensive inspections on our structural survey and structural inspection page. * Prices are a guide only and VAT may be added.
How much does crack monitoring cost?
A full year of crack monitoring, with our certificate of structural adequacy at the end if the readings show the structure is stable, costs from £2,100*.
The final price depends on the size of the house and how many cracks need gauges. Shorter monitoring, for example through one summer and autumn, is quoted once we know what needs watching. Either way, you get the price in writing before you book.
If you have not had an inspection yet, start with a Specific Structural Inspection from £420* or a General Structural Inspection from £590*. If monitoring is needed, the engineer will say so in the report.
Twelve months of monitoring
from £2,100*
- First visit, inspection and gauges fixed
- Return visits through the year
- Every reading, with photographs
- Our conclusion and advice on repairs
- Our certificate if the readings are stable
* Prices are a guide only and VAT may be added.
Why homeowners choose us for crack monitoring
- Engineers read the results. A qualified structural engineer interprets every set of readings, not just records them.
- A plain answer at the end. Historic, seasonal or ongoing, what is causing it and what to do next, in plain English.
- A certificate when it is earned. After a full year of stable readings we issue our own certificate of structural adequacy.
- We know London's clay. Our office is in Chiswick, and we have inspected Victorian and Edwardian homes across London since 2016.
- Your price in writing first. You know the full cost of the monitoring before you book.
They provided a very professional and detailed report for my insurance purposes, and everything was handled efficiently and thoroughly. The report was clear, accurate, and well presented, which made the insurance process much easier for me.
Monitoring a crack yourself
You can keep an eye on a crack before you call anyone. Mark each end lightly in pencil with the date, measure the widest point, and photograph it with a ruler held against it from the same spot each time.
Plastic tell-tale gauges are also sold in DIY shops. They are useful for your own peace of mind, but insurers, lenders and buyers' solicitors usually want readings taken and interpreted by an independent engineer, and a gauge in the wrong place can miss the movement that matters.
Crack monitoring: common questions
How long does crack monitoring take?
Usually several months, so that the readings cover a change of season. When you need our certificate of structural adequacy, monitoring runs for a full year, because clay soils shrink in summer and swell in winter and a year captures both. We recommend a period at the first visit, based on what we find and who needs the results.
How often do you read the gauges?
We agree the schedule when we fix the gauges, based on how active the cracking looks and what the results are for. The visits are spread through the monitoring period so the readings catch both the dry and the wet months. If a reading changes sharply, we contact you and advise on what to do next.
How much does crack monitoring cost?
A full year of crack monitoring, with our certificate at the end if the readings show the structure is stable, costs from £2,100*. The final price depends on the size of the house and how many cracks need gauges, and shorter monitoring is quoted once we know what needs watching. You get the price in writing before you book. Prices as of October 2026.
What is a tell-tale crack monitor?
A small gauge made of two overlapping plates. One is fixed on each side of the crack: one carries a millimetre grid and the other is clear, with a red cross. If the crack opens, closes or one side drops, the cross moves over the grid, so each reading shows movement both across the crack and up and down.
Will the gauges mark my walls?
The gauges are small and fixed to the surface on each side of the crack. When monitoring ends and they are removed, they can leave small marks to fill and paint, usually done with the crack repairs. Please do not move, paint over or knock a gauge while it is in place, as that spoils the readings.
Can I monitor a crack myself?
Yes, for your own peace of mind. Mark each end in pencil with the date, measure the widest point and photograph it from the same spot each time. Insurers, lenders and buyers' solicitors usually want readings taken and interpreted by an independent engineer.
Will my insurer or the buyer's solicitor accept your monitoring?
Independent monitoring by a structural engineer is often what they ask for, but the decision is theirs. Check with them first, and tell us what they have asked for, so the monitoring and our conclusion answer their question.
What happens if the crack is still moving?
We explain the likely cause and what to do next. That may mean checking the drains, trial pits to look at the foundations and soil, advice on nearby trees, or telling your insurer. Our structural survey and structural inspection page explains the inspections that start that work.
Can crack monitoring start in winter?
Yes. Monitoring can start in any month. A full year covers every season whichever month it begins. If you only need a few months of readings, the dry summer and autumn months usually show most about clay movement.
Do you cover my area?
Our office is in Chiswick and we monitor homes across Greater London. See the areas we cover, or send us your postcode and we will confirm.
