The crack in the wall wasn’t actually the problem.

The ground disappearing beneath the building was.

cracking

We were recently asked to look at cracking and localised movement beside a large historic building.

At first glance, it looked like a fairly typical movement issue. But further investigation revealed something much more serious.

A sinkhole had formed next to the building.

Our investigation identified a likely link between the drainage system and the movement we were seeing. The site sits on sand and gravel over chalk bedrock, conditions that can become problematic when drains leak over long periods of time.

As water escapes into the ground, it can wash out fine material within the soil and create pathways into the chalk below. Over time, this can lead to voids forming beneath the surface.

Once movement starts, the problem often gets worse quickly:

movement damages drains
damaged drains leak more
more water enters the ground
further movement occurs

On older sites, especially where drainage systems are ageing, these problems can stay hidden for years before signs begin appearing inside the building.

The defects we observed included:

cracking to masonry
movement above openings
sloping floors
ceiling cracking
drainage defects
localised settlement

To understand the extent and cause of the movement, we recommended:

CCTV drainage surveys
trial pits and boreholes
dynamic probing
crack monitoring
satellite ground movement monitoring

Importantly, repairing cracks before understanding the underlying cause can be a costly mistake.

Too often, cosmetic repairs are carried out while the actual mechanism causing the movement remains active beneath the building.

This is why structural investigations matter.

At Michael Aubrey Structural Engineers, a large part of our work involves diagnosing existing building problems and understanding why movement is occurring, not just repairing the symptoms.

#StructuralEngineering #Sinkhole #Subsidence #GroundMovement #BuildingDefects #StructuralInvestigation #structuraldetective

Cracks are often treated as the problem. In reality, they’re usually the warning sign.

The real question is: what’s happening beneath the surface?

Call us today if you have any concerns about properties you own or manage. t. 0118 962 9666

Structural Engineers Can Help Save Trees in Subsidence Disputes

In the wake of growing concern over the felling of protected trees due to subsidence claims, a question worth asking is:

Are we exhausting all technical alternatives before reaching for the chainsaw?

Across the UK, councils are being forced to choose between preserving mature trees and avoiding the financial risk of property damage claims. With insurers warning of costly repair liabilities, some local authorities feel they have no option but to approve the removal of trees under Tree Preservation Orders (TPOs) even when the evidence linking those trees to the damage is unclear or incomplete.

But structural engineers can offer another way.

Alternative explanations upon deeper investigation

As Chartered Structural Engineers with experience in diagnosing and managing subsidence, we regularly work on cases where trees are initially assumed to be the cause of movement only to find alternative explanations upon deeper investigation.

Our role is to provide objective, technical analysis that goes beyond surface assumptions and helps decision-makers understand the real cause of the damage.

Where trees are a contributing factor, that doesn’t mean felling is the only answer. There are a range of engineering-led solutions from tree root barriers and underpinning, to load redistribution and ground improvement that can stabilise buildings without destroying valuable canopy cover.

Expert technical support

We believe local authorities should feel confident resisting pressure to approve tree removals when evidence is weak or when mitigation is viable.

But to do so, they need expert technical support and strong documentation that can stand up to scrutiny from insurers and tribunals.

Structural engineers add value

One recent case involving Enfield Council demonstrated that councils can successfully defend themselves when evidence for tree-related subsidence is insufficient.

That’s exactly where structural engineers add value: delivering the kind of

detailed investigations
monitoring data, and
reasoned analysis

that makes those defences possible.

Our aim is to work alongside tree officers, insurers, and councils to protect both the built environment and the natural landscape. Mature trees take decades to grow but only minutes to lose. When budgets are tight and legal risks are high, engineering insight can help preserve both.

We want to support tree officers, surveyors, and local authorities in managing complex subsidence cases. Our goal is to help councils make confident, defensible decisions, preserving mature trees wherever possible.

With the right technical input, tree removal doesn’t have to be the default.

Contact Us

Book a free, no-obligation call to explore how we can help you protect structures without sacrificing trees.

Call us today on 0118 962 9666.

Not just a service, it’s how we think.

Before we put pen to paper or open a REVIT file, we do something different: we investigate.

The Structural Detective™ is our method, a calm, curious, forensic approach to understanding existing buildings before any design decisions are made. It’s not an add-on. It’s built into the way we work.

We start by asking:

What’s going on here? What’s this building trying to tell us?

Whether it’s a visible crack, a planned change of use, or a complex refurbishment, we look beneath the surface. We question assumptions, trace the building’s history, and gather evidence that reveals how the structure really works and why it might not be.

Why Our Method Matters

Too often, structural advice is based on guesswork, outdated drawings, or quick site visits.

That’s not how we work.

By taking the time to properly investigate your building, we can:

Spot issues early before they become expensive mistakes
Design smarter solutions that fit the reality on site
Give you advice you can trust based on evidence, not assumptions

What Being The Structural Detective™ Means

Every building has a backstory.
Before we make any structural recommendation, we aim to understand:

How it was built
How it’s changed over time
What it’s telling us through signs like cracks, movement, or materials

Our investigations might include:

Reviewing old drawings or records
Visual inspections and monitoring
Careful intrusive works to expose foundations, wall build-ups, or hidden defects

Once we’ve built the full picture, then we recommend action

Who We Help

Building Owners – Understand the true condition of your property before committing to costly works
Developers – De-risk projects by uncovering structural constraints early
Property Managers – Maintain safe, compliant buildings with informed planning

Experience You Can Trust

Being a Structural Detective takes more than a toolbox it takes experience, technical judgement, and a sharp eye for detail.

Our engineers are qualified, experienced, and specialised in existing buildings
We’ve carried out thousands of investigations across schools, offices, homes, and heritage sites
We bring confidence, clarity, and credibility from day one

Services We Offer

Structural Investigations
Defect Diagnosis (cracks, movement, subsidence)
Maintenance & Refurbishment Advice
Foundation & Load Assessments

Start with Understanding

If you’re working with an existing building, don’t jump straight to solutions.

Start with understanding.

That’s what The Structural Detective™ is all about.

Today I’m talking to John Staves, Chartered Structural Engineer about the increasing number of insurance claims for subsidence. 2023 saw a dramatic rise in the cases of subsidence as the UK experienced recording breaking dry weather.

John, What Has Been Your Experience of Subsidence?

Since mid 2023 enquiries in our office relating to “cracks in walls” have doubled. Understandably homeowners are worried that their house is falling down.

How Can People Tell The Difference Between Subsidence and General Wear and Tear?

New houses usually settle during the first few months and even years after construction, so minor wall cracks are likely.These are usually due to thermal movement and often occur at changes in construction such as between a wall and a ceiling and around door frames.However, gaping cracks, separation and horizontal crack lines might be signs that the issues are more severe.

They are usually diagonal, and wider at the top than the bottom;
They tend to be thicker than a 10p coin;
They are often found around doors and windows;
Subsidence may also cause dry wallpaper to rip or crinkle and;
Doors and windows may start to stick

What Is Subsidence?

Subsidence is defined as;“the gradual caving in or sinking of an area of land.”

What Are The Causes of Subsidence?

Generally, there are two types of Subsidence;

One-off type Movements – often caused by leaking drains. Worse where the ground is granular, as a leaking drain washes out the fines in a granular soil. If you repair the drain, then make good the cracking in the house, there should be be no further movement.

Seasonal Movement – often caused by the ground drying out (made worse in clay soils and/or you are near to certain types of trees).Once movement has been monitored, you are best to underpin the property so that the foundations are founded on soils that are no longer subject to seasonal change.

9 Most Popular Questions About Subsidence

Should I Buy A House That Has Had Subsidence?

Insurers and mortgage lenders are nervous about properties that have either had subsidence or are near to properties that have had subsidence – it seems to blight a property.If the property has had subsidence and it has been repaired eg underpinned, it’s on very good foundations now and isn’t likely to move again.However, the re-sale value will likely be low and it might be expensive obtaining house insurance in the future.

Can You Sell Your House If It’s Had Subsidence?

Yes you can, however it’s likely that the value will be slightly reduced and it might put off potential buyers who are risk-averse.

I think My House Has Subsidence – Can It Be Reversed? What Actions Can I Take?

It depends on the extent of the cracking and what caused the cracking in the first place.You would need to find out if the building still moving – ideally appoint a Structural Engineer who would carry out a detailed investigation.

Trial Holes

To identify the depth of your existing house foundations, trail holes would need to be dug adjacent to your house (your Structural Engineer should be able to arrange this for you).This would confirm the depth of your existing foundations and also what type of soil they are founded on.In the Thames Valley, the main cause of subsidence is clay soils.Soil samples may be taken and tested.

How Do You Monitor The Cracking?

Your Structural Engineer will need to establish whether the crack is increasing in size. The best method for measuring crack movements is by use of a crack monitor or ‘tell-tale‘.

Once the “tell-tale” is fixed in position an initial reading is taken. Then more readings are taken at regular intervals to establish if movement is occurring and if so, at what rate. By comparing the different rates of movement for cracks at different locations in a building, the cause and location of the weakness can be established.

The monitors should be left in place for as long as possible to establish whether the crack is moving or not and for a minimum of eight weeks.

Subsidence Cracking

The shape of the crack can tell us which part of the building is moving, in which direction, relative to the other parts of the building.

Cracks can be vertical – a vertical shear. This normally occurs if your foundations are founded on different types of soil and your house will “sink” on the side with the lowest bearing pressure.Usually, you get “rotational movement” – often cracking is wider at the top than the bottom.Or sometimes a corner of a house might have lifted, or the middle of a wall panel might have sagged.

What Is Underpinning?

Underpinning is a method used to increase foundation depth or repairing faulty foundations.If monitoring has established that movement has not stopped, your property can be underpinned.

The aim is to take your existing foundations down to a lower depth where they won’t be affected by seasonal movement and moisture change.This is normally carried out with mass concrete foundations (although there are other methods), designed by a Chartered Structural Engineer.

How Do I Repair Cracks in My Wall?

Cracks can be repaired by raking out the joins and re-pointing. If the cracks have gone through bricks, you’d normally replace the brick.In some cases, you might do something called “crack stitching” where you add reinforcing bars to the horizontal joints in the masonry to strengthening them ..stitch it all back together!

Will Subsidence Devalue My Home?

Yes, but mainly through ignorance and public perception. Once it has been mended it will be stronger than when it started out.

How Does Subsidence Affect Insurance?

Unfortunately, insurers take a very risk-averse approach and if there has been subsidence either at the property or even in the neighbouring properties in the same post code, you could find that the premiums are higher.

How Can Subsidence Be Prevented?

Making sure that your drains are well maintained so that they don’t have a chance of causing wash out if you are in granular soils.

By ensuring that your foundations aren’t within soils which change volume seasonally with moisture content (good design at the outset).Keep trees pruned and controlled at a steady height. Don’t drastically take the trees down as this will may lead to “heave”.By keeping the trees at a steady height the water demand will remain similar and all things being equal, it should be OK.The problem occurs when we have a very dry summer.

You get desiccation through natural evaporation through the surface, so you don’t have to have a tree nearby to get subsidence if your house is built on a clay soil because it will still dry out.Trees to avoid / ensure that they are planted a safe distance from your property; Willow, Poplar, Oak and Ash.

How Can a Structural Engineer help With Subsidence?

A Structural Engineer will determine what is actually happening by intrusive investigation, for example, trial holes to find out what the foundations are actually sat on.If we know we are on sandy soils and there is a drain nearby, it could be that there is a leak in that drain.

Normally this occurs on the bend in the pipe.If it goes unnoticed or ignored, it can cause wash out under the foundations.Sometimes it can also happen with heavy rainfall. If you get excessive water movement in the founding levels you get movement; if the water table rises you’ll get subsidence because the load bearing capacity of the ground reduces if its on a granular soil.

One of the problems in London is the rising water table because we don’t extract from the aqufa in the same way that we used to.A Structural Engineer is specialist and understand how a structure works and subsidence is clearly a structural issue.In this area of the UK, clay soil is the main cause of subsidence.

Get In Touch

Have you noticed cracking in your walls? Call Us today on 0118 962 9666 for a Free, no obligation consultation.

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What is a Certificate of Structural Adequacy?

A Certificate of Structural Adequacy is issued if you have had work completed on your property, typically where you have had subsidence, heave, or landslip. It can also be issued by an independent Chartered Structural Engineer to provide reassurance to the building owner that what has been built, is what was designed.

In the case of subsidence, the certificate of structural adequacy details the causes of the damage, the repair work undertaken and confirms that the work was carried out correctly and that the property is now structurally sound.

Who Usually Issues a Certificate of Structural Adequacy?

Loss adjusters, mortgage providers and insurers normally require the certificate to be issued by a Chartered Member of the Institution of Structural Engineers.

When is a Certificate of Structural Adequacy Issued?

Following completion of any building work and/or structural repairs and (in the case of underpinning) after a period of monitoring.

Is Building Regulations Approval Required for Structural Repairs eg underpinning aswell?

Yes. If you are carrying out underpinning work, under the Building Regulations it is deemed to be “building work” and would require Building Regulation approval.

Can I Get A Retrospective Certificate of Structural Adequacy?

Yes, but you would need to expose all of the structural elements of the build so that the engineer would be able to see that what has been built is correct (eg. as per the engineers’ design drawings), so the best thing is to have the engineer inspect during the works

Why Do I need a Certificate of Structural Adequacy if I have obtained Building Regulations Approval – Building Control Inspect Don’t They?

Building control only inspect a limited number of parts of the build.

The Chartered structural engineer would inspect at regular intervals to check to make sure that his/her design was implemented correctly. The Certificate of Structural Adequacy closes the loop. It makes sure that the builder has built what he has been paid to build.

Does A Certificate of Structural Adequacy Guarantee the Work?

In effect, the structural work will be guaranteed by the chartered engineers’ professional liability insurance. This insurance covers the design and advice provided and with satisfactory inspections it is clear where responsibility lies. If the builder hasn’t correctly implemented the design, this devalues the benefit of the insurance.

How much does a Certificate of Structural Adequacy Cost?

They can vary from £195+VAT to £295+VAT .

How Much Does Is Cost To Have a Chartered Structural Engineer Oversee The Build?

Again, this can vary, depending on the complexity of the job and hence the number of visits required to ensure the design is correctly implemented.

A Recent Example

This was a small project in Reading, Berkshire but demonstrates what can go wrong when you trust the builder to follow the approved plans, without any independent checks

The client obtained Building regulations approval for their project.
The builder built what he thought was correct (didn’t follow the drawings).
The client was none the wiser, as they didn’t know how to read the drawings.
The builder didn’t call out building control to inspect the works (even though there was a building control application and inspections should have been made).
Only after the works were completed did the client realise – he hadn’t received anything from building control.
Building control confirmed that they hadn’t inspected at all.
The client had photographs of the works being carried out, unfortunately, it was clear that the builder had not built to the approved drawings.

How Did the Client Resolve The Matter?

Sadly, this is not yet resolved.

The builder left site with the clients money and the client is left with a bill to sort out, or live with a structural defect and a potentially devalued property (as conveyancing solicitors would typically warn their clients not to buy a property without the final completion certificate).

The 3 Key Questions To Ask Yourself before You Start Your Project.

Do you understand what those stages are when building control need to inspect?
How are you making sure that the builder is notifying building control to check the work at the right time?
Are you confident doing that?

Are You Having Building Work Carried Out On Your Home?

Would you like an independent engineer to inspect the works as they proceed?

Please contact us today to see how we can help you.