What is subsidence?

Subsidence is the downward movement of the ground supporting the building, where the movement is unconnected with the weight of the building. Essentially, the soil beneath the building’s foundations is unstable and settlement occurs when the ground bearing the structure yields under the load of the building. It compresses to such an extent that the structure settles at the point of failure. Particular problems arise when the movement varies from one part of the building to another and causes walls to crack.

Why it is important to rectify subsidence quickly?

Cracking due to subsidence will affect the sale of your property. When selling, banks may be reluctant to finance the purchase of property with subsidence problems. If you sell it may be to a very restricted pool of purchasers e.g. cash buyers from a building background. Once subsidence is discovered on a survey by a purchaser, they may naturally request a large discount on price to cover potential subsidence repair cost. If left unresolved the repairs costs can escalate resulting potentially in rebuilding large sections of the property at much greater costs.

Why hire a subsidence engineer?

PKT as chartered subsidence engineers can certify subsidence repairs to reflect the fact that the building has been returned to its condition prior to the problem. We are subsidence specialists based in Dublin and have been investigating subsidence problems for over 30 years. We can manage your subsidence repair and insurance claim from start to finish and prepare a structural report for submittal to your insurance.

We can tender the repairs to specialist subsidence contractors on your behalf, who will offer an additional guarantee for the works to be covered. If Underpinning works are required we will advise on design options. We will carry out interim inspections of the construction phase including underpinning and structural repair works with certification upon completion. Therefore you have piece of mind that the works have been overseen by a chartered engineer to ensure they meet the specification and budget.

If you have noticed cracking or movement in your property, Call 01 491 2415 today or email us at info@pkt.ie to discuss whether it's necessary to carry out a subsidence assessment survey.


When we discovered we had subsidence problems in our house we employed PKT consulting engineers. PKT took over, all dealings with insurance company's assessors, the piling engineers and the builders. Kevin Tierney identified the extent of our problem designed the solution and oversaw the piling engineers and the builder's implementation of that solution. Kevin oversaw every part of the project from start to finish. We felt he made sure we got everything we paid for and weren't charged for what we didn't need. All in all, he took an 85 year old house suffering from subsidence and made sure it has been left rock solid for the next 100 years. Kevin was a pleasure to deal with straight forward and easy to talk to. We would have no hesitation recommending PKT Consulting Engineers. Brendan & Valerie, Drumcondra

Kevin looked after the project from claim stage when he diagnosed subsidence. He dealt with the subsidence insurance claim, applied for planning for my protected period house, tendered the project and oversaw construction. I found him to be efficient, cheerful with a can do attitude and he was available to me whenever I needed to contact him. He was also dogged, persistant and determined when negotiating with the difficulties of what was a complex building project. I would definitely recommend Kevin's expertise. Deirdre, Rathgar, Dublin, Ireland. 7.4.2015

What are the signs of subsidence?

Identifying the cause of subsidence begins with exploring its consequences. The emergence of cracks is the first obvious signs of subsidence. Nevertheless, not all cracks indicate that there is a problem. There could be movement in the ground beneath your building if you find:

  • • Vertical and diagonal cracking concentrated in specific areas tapering in width between the top and bottom of the building. Horizontal cracks may also occur.
  • • Cracks extending through the DPC down into the foundations.
  • • External cracking reflected internally in the same area of the wall.
  • • Deformity of doors and windows, which are weak areas in a building, causing doors and windows to stick.
  • • Floors sloped and walls leaning.
  • • Rippling wallpaper that isn’t caused by damp.

What causes subsidence?

  • Certain soils: Clay soils are particularly vulnerable to subsidence since they shrink and swell depending on their moisture content. The compression of filled ground can also cause subsidence.
  • Vegetation: Trees and shrubs take moisture from soils causing them to shrink. This is intensified during long dry spells of weather as roots extend in search of water.
  • Leaking drains and watermains: Leaking drains and watermains can weaken the supporting subsoil or wash out the fine minerals within the soil, causing settlement of the building foundation.
  • Property location: Problems may occur where houses are built over, or close to mining and quarry works. This is not that common.
  • Excavations adjacent to building: Can cause subsidence unless proper precautions are taken to support the building in advance and restraining the sides of the excavation.
  • Vibration: The ground compacts and shrinks, weakening the subsoil, reducing the capacity of the subsoil to support the building above.

Does building insurance cover subsidence?

Usually, subsidence claims are covered unless expressly excluded from your building insurance policy.
TIP: It is not advisable to shop around yearly for building insurance to avoid issues in the future if you suffer subsidence and need to make a claim. It can be challenging to establish liability if there are multiple insurers over the years. This is different for other insurances, e.g., car insurance, etc.

My insurer's loss adjuster wants to appoint their engineer. Can I still appoint my engineer?

You can usually employ your engineer under the terms of your policy and have their reasonable costs covered under your policy unless it's expressly excluded. Ask to be shown the wording by the insurer's loss adjuster if you are told you can’t appoint your own engineers. The insurers will usually always appoint their engineer and loss adjuster on a subsidence claim to advise them. However, we recommend appointing your own subsidence engineer and loss assessor to represent you during the insurance claim process.
TIP: If you receive consultancy advice, ensuring you have a contract signed with whomever you receive professional advice from is strongly advisable. The insurers should refund the reasonable professional fees if liability is accepted.

How quickly do subsidence cracks appear?

Subsidence cracking can occur at any time, but typically, after an event like a leaking drain, water pipe, etc., washing away or softening ground below foundations, other triggers can occur to undermine the foundations. How quickly and to what extent the subsidence cracks appear can depend on factors like soil conditions, the extent of a pipe leak, or other trigger events. It is important to note that cracking can have different causes, not just subsidence, so it's important to employ a chartered engineer to investigate. If subsidence is established, PKT can prepare a proposed solution for pricing.

What is the difference between settlement and subsidence?

Subsidence is the downward movement of the ground supporting the building, which is unconnected with the weight of the building. Essentially, the soil beneath the building’s foundations is unstable, and settlement occurs when the ground bearing the structure yields under the load of the building. Settlement is not covered under your insurance, but subsidence is usually covered.

What is the impact of subsidence on buildings?

If the movement is progressive and left unrepaired, the building can deteriorate structurally, possibly requiring more expensive solutions to repair or demolition in extreme situations. In my experience, the cost of subsidence repairs increases the longer the building subsidence movement is left in progress.

How much does subsidence devalue the property?

It would be best to discuss the current market values for similar properties with an estate agent. Still, he will need to know how much it would cost to repair the subsidence issue to give a more accurate potential value. An investigation by a chartered engineer with experience to assess the extent of the damage and potential repair solution would help this analysis. Depending on its extent, a subsidence issue can generally make it more challenging to sell. Banks may sometimes be reluctant to provide finance for the property or may want detailed costs for the required repairs.
TIP: Having the subsidence repairs specified, monitored, and certified by a chartered engineer would be beneficial.

How can you tell how severe subsidence is?

A full investigation by a chartered engineer would be required to establish the severity of the issue. There are several factors to assess, e.g., the extent of cracking and how rapidly it has progressed or is progressing. How badly has the existing structure deteriorated? The extent of floors sloping, doors sticking, extensive cracking, leaning walls, etc.

How to fix subsidence?

Various forms of Underpinning can be utilised to fix subsidence, but they depend on the age, construction type, access to property, extent of the subsidence, soil and foundation type, etc. A chartered engineer with experience in fixing subsidence will be able to advise on the best approach.
TIP: If your insurers accept liability and are repairing directly, we recommend, if possible, appointing your engineer to independently review their proposed method of underpinning and its suitability to resolve your issue entirely.

How much does subsidence cost to repair?

The subsidence repair price will depend on the extent of the issue, which would have to be assessed by a chartered engineer experienced in subsidence projects. Investigations, testing, and inspection would typically be required before the subsidence repair cost could be calculated. PKT would be happy to provide a quote for the same.

How do engineers check for subsidence?

PKT conducts an initial preliminary assessment to determine if subsidence is a potential cause and if immediate emergency temporary supports are required. This can be followed by testing and a follow-up report to confirm the extent of the problem and possible solutions.

How much does a subsidence survey cost?

The subsidence survey cost will depend on factors like the building's age, size and location. Please call our offices on 01 491 2415 or email us at info@pkt.ie to get a quote.

01 491 2415