What is Subsidence?
18 January 2022
If you own a property, then it’s more than likely that you are familiar with the concept of a buildings foundations. The foundations are the structure that an entire building sits on, and they are absolutely vital – especially if you want to keep your property in a maintained and healthy order.
So, if your property were to suffer from subsidence, what could that mean? How can subsidence effect your property, and what actions will need to be taken to remove the threat of subsidence from your property?
Please note: Timberwise does not undertake work to remedy subsidence directly.
What does Subsidence mean?
Subsidence is the term used when the very ground that sits beneath a property shifts or sinks, causing the building itself to move with it, which can mean that the property sinks on one side, or entirely as a result of the ground moving.
Even the smallest amount of subsidence can cause problems in a property. These can range from structural, to superficial, and all will require works to be undertaken in order to bring your property back into order.
The question though is how does subsidence occur, and what work can be done to fix any damage stemming from the subsidence itself?
What Causes Subsidence?
Subsidence can be caused by a number of different factors, each of which have their own distinct way of creating property care problems for the owner of the building effected by the subsidence in question.
Trees might well be decorative, pleasant, and ultimately benign at a surface level, even when they are located close to a property. However, the truth is that trees can have a serious and lasting effect on a property, not just due to the potential risk of a felled tree in the wind – but to subsidence.
For example, everyone knows that trees are alive, and exist by extracting nutrients and moisture out of the soil in which they are planted. However, if a tree is large enough, it could draw in enough water out of the soil surrounding it that the actual clay in the soil shrinks, causing the ground to shift and subsidence to occur as a result.
Of course, this kind of subsidence is dependent entirely on the trees overall size, as well as the amount of water that its capable of sucking up on a given day. You might also find that trees are responsible for subsidence in another way: via their roots.
If a tree has roots that extend underneath or around a properties foundations you may find that the roots themselves can cause the ground to shift slowly and elevate certain areas of the foundation that the roots extend underneath – or vice versa, you may see the foundations dip where roots extend over the foundations and push down.
This kind of subsidence might build up over time, but if you do have trees close to your property it may well be worth having a professional survey carried out of the area to see just how at risk you are from subsidence caused by nearby trees.
Inferior Quality Foundations
Sometimes a properties foundations themselves are the very reason that subsidence occurs. Take older properties for example. It’s, unfortunately, the case that many older properties throughout the UK have shallower foundations than those found in newer build homes.
This means that those foundations are much more susceptible to surface level problems. These can range from flooding, to things you might not have even considered. For example, if you are situated near to a busy road, the rumbles and vibrations of cars, vans, and (more often) lorries can over time cause the earth to shift and sag – which in properties with foundations closer to the surface is much more dangerous.
Then there is the question of the materials used in the construction of the foundations themselves. The wrong materials, older or less sturdy materials, or failing materials can all contribute to the same foundations shifting, and causing subsidence.
If you are concerned that your property is a little older and might have foundations prone to failure, you can always pursue a professional survey, just so any potential risks that might stem from your properties foundations can be possibly identified and highlighted to you.
Water damage can lead to subsidence simply through the erosion and break down of your properties below ground structures – including the foundations.
If your foundations are exposed to water below ground you may find that the onset of damp and the continued exposure to moisture leads to a downturn in the health of the foundations themselves. This can sadly lead to cracks, crumbling, and eventually a shift in your properties position due to the failure of your foundations.
Ensuring that your foundations can stand up to continued exposure to water is vital, and if you are concerned that your foundations might be suffering from water damage you can always enlist the help of a below ground waterproofing expert to help you decide whether work needs to be done on your properties foundation to fully waterproof them.
Clay in the Earth Shrinking
One of the most common and regularly experienced forms of subsidence is clay shrinkage. Clay shrinkage happens in warmer weather, when the water trapped within the clay found in the ground evaporates – causing the soil to shrink as a whole, which can lead to movement in the ground surrounding the area from which water has evaporated from.
This is a cause of subsidence that is incredibly common and, in periods when the heat is greater than normal – like during a heatwave, cases of subsidence can rise massively, as there is a greater amount of moisture leaving the earth and soil drying than usual.
Unfortunately, there is very little that can be done to prevent or predict clay shrinkage – however, if your property does sit on a clay rich area, and suffers subsidence in the summer following a heavy dry spell, then you could well have been victim of clay shrinkage.
Signs of Subsidence
In truth, you might not notice subsidence in your property just by looking at it. In many cases, subsidence can be very minor – but even a minor amount of sagging can lead to serious problems in your property that need to be rectified. So, how can you spot subsidence before it gets serious?
Cracks in the Walls
Whilst every crack in a wall might not be a sign of subsidence, you will find that many properties that do suffer from subsidence do have cracks in their walls. Luckily, cracks in walls caused by subsidence do have distinctive features to them, which make them easy to identify as being the fault of subsidence.
First, is the crack wider than 3cm at any point? This is a common sign that your crack is down to subsidence; if the crack can be measured as wider than 3cm (or roughly around the size of a 10p), then there is a good chance that the crack in the wall is down to subsidence rather than anything else.
You should also be on the lookout for cracks that appear on both the inside and the outside of a property. This can indicate that the crack runs through the wall, and is the result of subsidence – in this case, the shifting and sinking of the ground has led to the wall being displaced and cracking down the centre.
You should also suspect subsidence when you find cracks that appear around weak spots in your properties construction. By weak spots, we generally mean and refer to areas surrounding doors, windows or other frames built into your property, or around newer areas of your home.
Cracks that appear around extensions added to your property as well are generally considered to be signs of subsidence, the initial connection from the original property to the new build an area that might be susceptible to movement within foundations and the ground itself following work to extend the property.
Finally, if the crack itself is wider at the top than it is at the bottom then this could also be a sign that your property has fallen victim to subsidence. You might also notice other factors that could mean your property has become a victim of subsidence, such as wrinkling in your properties wallpaper when there is no evidence of condensation or damp could mean that your property is undergoing subsidence.
What Kind of Damage Can Subsidence Do?
If left alone subsidence can have a very real and very serious detrimental effect on your property. Here are just some of the ways that subsidence could effect your property.
Subsidence can have a devastating effect on the structural integrity of your property. This includes damage to foundations that might be costly and time consuming when it comes to repair and can even lead to additional damage occurring in the building materials themselves – potentially including water damage, which of course leads to damp, and the eventual degradation of the below ground building materials themselves.
This means that expensive below ground waterproofing may need to take place, including work to secure and waterproof your foundations alongside any basement you might have. This process is difficult, time consuming and expensive, so it’s best to have any suspected foundation problems looked at and surveyed as soon as possible.
Then, there is the potential for cosmetic damage in the property. This of course means cracks – but cracks that start as cosmetic damage only can quickly escalate to becoming serious issues. Cavity wall ties and crack stitching are both serious property care projects that need to be undertaken to fix cracks in exterior walls in some cases and are both often caused by subsidence.
Damage to Property Value
As any property owner knows, the value of a building is tied not only to location, market trends and seller expectation, but also to the valuation given by qualified surveyors working on both the buyer and lenders (where applicable) behalf.
This means if during the process of your house being sold a surveyor discovers that subsidence has occurred, you will have to face one of two prospects. The first being that you could have to lower the asking price of your home to account for the subsidence, or that you will have to pay for those repairs to be completed in order for the sale to proceed.
In either situation you are going to be jeopardising a potential sale, and possibly losing out on any other money you have invested into the sale of the property itself (solicitor fees, estate agent fees etc).
So, whilst it can be hard to predict or account for what may have cause subsidence in your property, before you take your property on the market you may want to have a surveyor look over the property privately, so that any repair work costs that are needed for foundation repair can be factored into the final sale price of the property itself, rather than having them crop up during the sale process and potentially costing you money and a sale.
How to Fix Subsidence
There are a number of different methods available to those who want to teat subsidence. One such method involved the injection of a resin below the building where the subsidence has taken place, so that any potential gaps can be filled easily.
Of course this work is complex. If you are hoping to have a subsidence issue at your property fixed, then you should contact a skilled professional who can undertake the work for you.
Please note: Timberwise does not undertake work to remedy subsidence directly.
If subsidence at your property has caused additional damage like the appearance of cracks, the emergence of damp in your walls, or other property care issues you would like taken care of, then do not hesitate to call Timberwise.
Our team of surveyors can help you restore your property to a healthy and well presented condition after the work to fix the subsidence has been completed. Just call 0800 288 8660 or get in touch online.