Signs Of Subsidence
Subsidence is a common problem in the UK, with approximately 6% of UK homes being affected. This occurrence can be a real hole in the pocket for homeowners, costing in the region of £10,000-£15,000 on average for remedial and preventative action.
What Is Subsidence?
Subsidence is the scientific term for a sinking ground. This is the downward vertical movement of either some or the whole area of the property for reasons other than the weight of an overlying structure. These ground movements can cause severe damage to buildings and possessions.
If you think ground subsidence could be a concern to your property, there are some indicators to look out for. These signs point to further trouble in the future. Spotting them early can save your home.
Cracks In The Walls
Cracks are usually harmless and not cause for concern, but subsidence cracks are different and characterised by a substantial partition in the wall, usually greater than an inch. These subsidence cracks come in three main variants to identify:
The vertical cracks will often be larger at the top and thinner at the bottom, as part of the floor becomes unsupported and falls at a slight angle.
The horizontal crack displays how the change in floor level has taken some of the wall down but put strain on the internal structure of the wall, causing the rest to fracture off instead of following the downward movement.
These types of subsidence cracks can be easily confused with horizontal settlement cracks, as they can appear identical. Settlement cracks occur as the ground level falls due to the downward force of the weight of the building itself, as opposed to soil degradation.
A horizontal crack is more likely to be subsidence when occurring after 5 or so years of construction, as the settlement cracks are likely to show up not too long after the weight is added to the ground, whereas a subsidence crack can occur at any time. As well as this, a subsidence crack is usually more severe on one side of the building, whereas a settlement crack may appear spread out more evenly across the building.
A step crack shows the line of least resistance in the mortar around the block or bricks, as the wall splits in two from the change in level of part of the building.
Sticking Doors And Windows
When the floor level changes, this can leave the fixed shape of a door or window wedged into place and seemingly immovable after the window or door frame is warped, cracked, or bent out of shape.
If your door or window one-day sticks shut, it could be due to the ground movement. Check the frame for any changes in shape or cracks that might suggest the wall has been put under stress.
Trees Near The House
There are a few signs of subsidence risk that are noteworthy before noticeable ground movement takes place. Any tree can be a cause of subsidence, and especially thirsty trees on clay-rich soil.
There are certain trees to look out for, such as the willow, poplar, ash, and oak, which could be causing existing damage or putting your property in danger of future subsidence. The willow tree in particular is synonymous with river and lake environments, as they require enormous amounts of water, and are known to absorb up to 1000 litres a day.
Without sufficient rain, the tree’s water quota can drain the soil of its moisture, leading to the ground falling away, and possibly damaging your property.
A willow or other thirsty tree can be a danger within 40 metres, a large tree can cause subsidence if it’s within around 20 metres, and a smaller tree should not be a risk further than 5 metres from the house.
Another concern is the actual roots of the tree uplifting the soil under the building and causing cracks.
Another danger sign is clay-rich soil. The UK has a relatively high amount of clay in its soils due mainly to the huge volume of rivers running across the country through history, depositing a clay-rich soil.
These soils are water-dense, which suspends the particles. When the clay dries out, it reduces in volume, causing the ground level to fall. The drying out of these soils is the number one concern when we look at causes of subsidence.
Home Insurance Providers
A subsidence excess or condition on any insurance policy will suggest that there is a subsidence concern for the property and would warrant an extra careful search for any of these signs. If the property has a history of subsidence, insurance is still available as a specialist home subsidence insurance product
If there isn’t anything to suggest that the subsidence risk is out of the ordinary, you can check a subsidence map online or get in contact with your current insurance provider. They will be able to give you an idea of the risk in your area and whether the best course of action is to get professional advice from a surveyor.