Subsidence or Settlement? Either way there's no need to panic!

If you find a crack in your home, or have a Valuation Survey or Homebuyers Survey and the surveyor identifies cracking, you need to get a Chartered Structural Engineer's Report to clarify the problem. Cracking to buildings can be caused by many things and in most cases we will be able to spot the probable reason during our inspection. If the cracking is suspected of being due to subsidence then we can help you resolve the problem. Before covering how we are able to help it is worth you understanding exactly what subsidence is.

What is the difference?
With subsidence the supporting soil moves away from the structure taking away its support and allowing the structure to move. Settlement is where the structure moves the soil due to application of load.

Settlement normally occurs early in the life of a property whereas subsidence can occur at any time. In a large part of the South East of England we have large areas of Clay Subsoil and movement of this is the main cause of subsidence problems. Subsidence is normally covered by insurance whereas settlement is not.

When clay becomes dry its volume changes. You have probably seen the images on television during droughts where reservoirs are empty and they show the crazed and cracked ground. Subsidence in clay happens when the ground dries and shrinks below the foundations. The change in volume takes away the support for the foundations.

In many cases there is enough inherent strength in a building and it cracks. If the volume change of the supporting soil is enough, at some stage the structure will fracture allowing the unsupported section of the building to drop. This often results in tapered cracks extending up through the building accompanied by rotational movement as shown in the photograph.

The ground tends to move with the seasons as its moisture content changes. Most modern buildings have foundations dug deep enough into the ground that they avoid the bulk of this ground movement. Even for properties with shallow foundations this ground movement may not be a problem if the movement is uniform. Variations of movement across a building are where problems occur.

Trees, often the "root of the problem..."
A common problem is when there are trees and vegetation close to a property. During dry conditions the trees extract more moisture from the soil. This produces greater movements to the subsoil closer to the tree and this differential movement results in subsidence cracking. To resolve the problem an engineering assessment has to be made to decide on the best courses of action. With trees, often the trees causing the problem are removed. Sometimes this may not be possible if there are tree preservation orders or if removing the tree may result in other potentially more severe damage. In some cases underpinning may be the appropriate solution.

Underpinning often concerns clients, but is really not as worrying as you think. In effect underpinning is a practical way of putting the correct foundations under a building where the originals are inadequate. It could be argued, therefore, that the underpinned building is actually better than a neighbouring building that has not been underpinned. The underpinned building now has the correct foundations whereas the other one is waiting to fail.

My building has Subsidence - what do I do?
Firstly you need a Chartered Structural Engineers Report to identify that the damage really is subsidence. If subsidence is proved and an insurance claim accepted the cost of this report normally forms part of the claim, typically coming out of the policy excess.

Once you have the Chartered Structural Engineers Report you send this along with a claim form to the Insurance Company and they will normally appoint a Loss Adjuster who will handle how the claim is dealt with. It is important for you to know what your insurance policy covers before the first meeting with the Loss Adjuster.

Some policies state that the insurer will appoint the experts to deal with the claim and also the contractors to carry out the repairs. They suggest this is beneficial to you, taking away the worry over the matter, but we have found this is not always the case. We have come across many cases where decisions on remedial action are taken by unqualified people, where poor or incorrect decisions are made and where repairs carried out are of poor quality or inadequate.

The problem is that there is no-one looking after your interests. In cases where you have no say in how the works are managed we can assist by providing an overview of the events and giving you the help you need to ensure the end solution is acceptable. However, in most cases, our fees for this work are not covered by the insurer.

A lot of policies allow you to have an Engineer of your choice to oversee the works and we are pleased to be able to offer this service. In these cases our 'reasonable fees' are covered by the insurance company. The advantage of this approach is that you benefit from our expertise to determine the correct engineering solution and not just the cheapest option which so often seems to be the situation when works are directed by the Loss Adjusters. Even when you are entitled to have your own engineer overseeing the works, some Loss Adjusters try to impose their own design team on you. This is potentially a very poor option! In these cases, often all they are doing is generating more business for themselves, rather than giving you a better service.

Loss Adjusters are appointed by the insurance companies to determine the extent of their liability. Insurers will tend to appoint loss adjusters who overall result in lower levels of claims settlement and hence there is some incentive for loss adjusters to minimise the scope of the repairs. As independent engineers we are driven by a determination to ascertain the correct engineering solution not just the cheapest option.

Our advice is to find out if you have the option to have your own Engineer acting for you and if you do...TAKE IT!

Our normal approach to subsidence issues is to carry out whatever investigation is necessary to determine the cause of the problem. Just because there is a tree nearby doesn't mean that is the cause. We normally recommend a trial hole investigation to try to discover the cause and to then decide on the best way forward. Often monitoring is required to determine if the building is still moving or, if a cause has been removed, to see when the property has recovered and/or stabilised.

Once a course of action has been established we will draw up a Schedule of Works. Next we'll obtain tenders from suitable contractors and oversee the works to completion for you, providing contract administration, supervision and sanctioning payments along the way. We will also arrange all the necessary Local Authority approvals and where appropriate deal with any Party Wall issues.

Other Causes of Subsidence
In addition to problems due to clay shrinkage there are a number of other possible subsidence causes.

Granular Soils:
In granular soils like sands and gravels, leaking drains can wash away the fine content of the soil and this produces a change in volume of the soil which can lead to subsidence. In granular soils where subsidence is suspected it is normal to check drains and water mains for leakage. Trees do not usually affect granular soils as they are normally non shrinkable.

Chalk Soils:
Most chalk is non-shrinkable and so trees do not normally cause a problem. Sometimes, however, there are areas of clay over the chalk or the upper layers of chalk can have a clay content. Tests normally have to be carried out to determine the soil characteristics when assessing a potential subsidence problem. Leaking drains can dissolve or soften the chalk resulting in foundation movements so again drain testing is normally carried out.

In chalk you can get 'Swallow Holes' or 'Solution Features' which are where a void forms below ground. These are normally hidden from view but under the right conditions the capping over it can fail and a void open up. If this happens below a house the damage can be significant.

Mine Workings:
In coal mining areas there can be substantial ground movements from old mine workings as they collapse but luckily this is not prevalent in the Beds, Herts and Bucks area. There are chalk mines in this area and in particular around Stevenage, where we have had to deal with a 6m deep hole opening up below the corner of a client's house.

Insurance Issues
The rise in popularity of price comparison web sites and the advice of money management “gurus” is to keep shopping around for the cheapest suppliers. This can be good advice with car insurance and utilities but changing Buildings and Contents Insurance can be bad news if your house has a subsidence problem.

If you are certain your house has no problems, changing insurer is no real issue but often the lay person may not recognise their house has a problem. If you change insurer and a subsidence problem is identified soon after the change, there may be a problem deciding which insurer should cover it. The Association of British Insurers (ABI) says that if a claim is made within the first eight weeks of the changeover, the previous insurer will deal with it. Claims between 8 weeks and 1 year will be handled by the new insurer with the cost of settlement shared equally between the two insurers. This agreement, the ABI say, is subscribed to by the "majority of household insurers."

The problem occurs when there are signs of historic damage as well as the new damage. If the historic damage was not notified to the new insurer when the policy is taken out they may not cover the repairs or could even cancel the insurance due to non-disclosure.

It is a better prospect to insure with a main stream insurer and to stay with them long term to build up a provenance so if a problem occurs there is no dispute over pre-inception damage.   It is also important not to "under-insure".  When you insure a property you need it to provide rebuilding cost following maybe a serious fire or the like.  The problem here is that if there are serious ground issues the cost of solving these can be extremely high and you don't want to find you're under-insured.

We dealt with a case where, following subsidence, a group of three properties had to be underpinned by installing a piled foundation. The ground conditions were very difficult and the costs of the remedial works were higher than the sum insured.  The insurance company paid out the full sum insured, and then cancelled the policy.  Without enough to pay for repairs and no on-going insurance the houses were effectively worthless. The client ended up having to pay out a significant sum to complete the repairs.

Subsidence and Selling Properties
If a property has a subsidence problem, historically had a subsidence problem or a claim has been made and not accepted… there is likely to be an issue with insurance. Most main stream insurers will not take on a new property where a subsidence problem exists or has existed.

If you have had a subsidence problem the best advice we can give you is…



If the policy lapses, some insurers will not reinstate it, leaving you with no cover.  Normally if you change insurer the only way you will be able to do this is to not declare the problem.  That is fraudulent and means the policy is invalid. If you have valid insurance at the time of the subsidence problem then most insurers will continue to insure your property and will have a way of continuing insurance when the property is sold. On selling your property the insurance company either will assign the policy to the new owner or will issue a new policy but linked to the old policy recording the fact that there has been a subsidence problem.

The first option is best as it effectively means the same policy continues, just the name on the policy gets changed.  This gives you the same rights as if the previous owner was still in residence.  The latter option seems to be the more common approach which is acceptable, provided there are no adverse conditions imposed. When arranging cover the insurers often like to make things difficult.

Often the first point of contact with the insurer will not be helpful and if necessary you will need to ask to speak to a supervisor. Normally once you get to speak to the right person the new policy is easily arranged. When arranging the transfer of cover make sure you do this on both buildings and contents cover.  Both cover different aspects of subsidence so both must stay with the old insurer.

When arranging insurance, particularly if the subsidence problem is on-going, have it recorded that any on-going or future claim covers all the damage and not just new damage from policy inception.

We had one job where a house had major subsidence which was repaired and the house was sold.  The new owner found some major issues with the works carried out (the living room floor was 75mm out of level!!) but when he contacted the insurer they said that as the works were prior to policy inception he had no rights for any further repair. If you are in this situation we recommend that you have the insurance checked by your solicitor to make sure there are no loopholes.

Subsidence and No Insurance
If you are in the situation of having subsidence and no insurance unfortunately your options are either paying for the repairs or selling at a low price due to the problems.  We can help you find the most economic way to resolve the problems.

If the property has been repaired following subsidence then generally none of the main stream insurers will insure the property.  We are brokers for a specialist insurer who will take on properties like this providing it meets their criteria.  Please contact us to discuss the problem.