What subsidence actually means for a buyer 

Subsidence happens when the ground beneath a property’s foundations loses support or moves, causing part of the structure to move differentially. This action often results in wide, diagonal cracks, sticking doors or windows and uneven floors.  

For potential buyers, there are three crucial things to consider:  

1. Why did the subsidence occur?

2. Has the underlying cause been remediated?

3. Is the ground movement ongoing or historic?

The third point is crucial as dealing with a property with historic subsidence is different from dealing with a property that’s currently experiencing subsidence. 

Does the seller have to tell you if there is subsidence? 

In Ireland, sellers are not legally required to declare structural issues such as subsidence if you don’t ask. For peace of mind, you should hire an engineering specialist to conduct an independent structural assessment and ask your solicitor to find information on the structural integrity of the property and its history.  

Buying a house that's already been underpinned 

If a property you’re interested in has been ‘underpinned’, it simply means that remedial work was carried out to address a problem with the foundations or ground conditions. It doesn’t necessarily mean you should walk away from the deal. In fact, it may give you peace of mind to know the property now sits on solid ground.  

What really matters is knowing why underpinning was required, what work was carried out and if the repairs successfully addressed the underlying problem. Before you make a firm commitment to purchasing an underpinned house, you should ask to see relevant documentation, such as: 

• An engineer’s or structural report

• Details exploring the cause of the original movement

• Documentation demonstrating completion of works

• Guarantees or warranties

• Evidence of the type of remedial works used

It’s important to know what repair method was used, not just that the property had been repaired. This is because different causes and ground conditions may need different approaches, and knowing what type of remedial works were carried out helps give peace of mind over the property’s long-term resilience. 

Questions to ask before you commit 

Before you commit to buying a house with a history of subsidence, you should first find out: 

• What caused the subsidence?

• Is subsidence ongoing?

• When was the issue identified?

• What remediation work was carried out?

• Who carried out the work?

• Was it overseen by a ground engineering specialist?

• Has the property remained stable since work was complete?

• Are there warranties or guarantees?

• Will the property be adequately insured?

• Will your mortgage lender accept the property?

Once you have the answers to these questions, you can make an informed decision that’s based on facts, not assumptions. 

Will you be able to get a mortgage or insurance? 

The short answer is that it depends on whether the subsidence is active or historic.  

If subsidence is active, lenders will most likely refuse to mortgage the property because it poses a significant structural and financial risk. Additionally, Irish insurers will not cover properties experiencing ground movement for the same reasons.  

If a property has experienced subsidence in the past, lenders may approve the mortgage, providing: 

• The ground movement has completely stopped.

• Remedial works have been carried out professionally.

• There is clear documentation to show the work has been completed e.g. a structural engineer’s report.

It’s worth noting, however, that major Irish insurers often turn buyers down or impose heavy restrictions on new subsidence cover in areas of high-risk areas such as parts of Cork, Galway or Clare. You should contact insurers to verify if they will provide subsidence cover as part of their buildings insurance for the property you intend to buy.  

Common causes of subsidence in Irish homes 

Different ground conditions can contribute to movement, so it’s important to understand what causes subsidence.  

Shrink-swell cycles. When moisture levels change, clay soils shrink during dry conditions and swell when conditions become wet again. This repeated cycle can cause ground movement beneath the foundations. 

Large trees and vegetation. Trees, shrubs and other types of vegetation can influence the moisture content in the soil beneath a property. During hot, dry weather, tree roots can draw significant amounts of water, causing the soil to shrink further.   

Poorly compacted or variable ground conditions. Made ground or poorly compacted fill can cause the foundations to sink unevenly when ground conditions change.  

Leaky pipes or damaged drainpipes. Excess water from leaky drainage can oversaturate the ground, washing away the supporting soil. This can lead to potential settlement or movement.  

Understanding the underlying causes of subsidence is essential to addressing the root cause of the problem. 

How Mainmark Ground Engineering can help 

The first step to understanding the cause and extent of subsidence on the property is to appoint a ground engineering specialist to investigate the site.  

Mainmark will visit the property in-person and conduct an assessment, which typically involves assessing visible signs of movement, reviewing available information and determining whether further investigation or remedial works may be appropriate. Once all the information has been gathered, a quote will be provided for the appropriate remediation works. In addition to underpinning, Mainmark specialises in a range of non-invasive ground improvement techniques such as resin injection, screw piles, root barriers and computer-controlled grouting, which are less disruptive than traditional methods. 

So, should you buy a house with subsidence? Ultimately, if the cause of subsidence is identified, the appropriate remediation works have been carried out and evidence of such work can be provided, it may still be worth buying the property. It’s essential that you have the right information before making a purchasing decision.  

If you need advice, contact Mainmark Ireland today.