What are the causes of ground subsidence?

Subsidence – sinking of the ground because of underground material movement—is most often caused by the removal of water, oil, natural gas, or mineral resources out of the ground by pumping, fracking, or mining activities.

What are effects of ground subsidence?

Subsidence causes permanent inundation of land, aggravates flooding, changes topographic gradients, ruptures the land surface, and reduces the capacity of aquifers to store water.

What causes subsidence?

Subsidence can be a homeowner’s worst nightmare as it can be a serious problem for your property. Subsidence is the sinking of the ground beneath your home, subsequently causing your home’s foundations to collapse and sink too, as its support, structure, and stability is weakened.

What are some of the causes and effects of ground subsidence?

Land subsidence is the gradual settling or sudden sinking of land. Its primary causes are the removal of underground water, compaction, drainage of organic soils, underground mining, and thawing permafrost. In Connecticut, the main causes are subsurface soil loss after heavy rains and abandoned mine collapse.

Where does ground subsidence usually occur?

In many areas of the arid Southwest, and in more humid areas underlain by soluble rocks such as limestone, gypsum, or salt, land subsidence is an often-overlooked environmental consequence of our land- and water-use practices.

How can we prevent soil subsidence?

Subsidence can be prevented by adequate support system (rib and sill pillars, steel and wood), cable and rock bolting, plugging of cracks, and backfilling by sand, cement-mixed tailing and waste rock.

What are the two types of subsidence?

• Surface Subsidence and Collapse.
• Carbonate Dissolution.
• Dissolution.

How do surveyors check for subsidence?

How to spot subsidence?

1. Large cracks (larger than 3mm) suddenly appearing in a wall, usually around a door or window frame, which are wider at the top than they are at the bottom.
2. Doors and windows sticking.
3. If you have an extension, look for cracks where the extension meets the main part of the house.

Is subsidence serious?

Subsidence is one of the most serious problems a property can suffer, potentially affecting not only your home’s structural safety, but also its resale value. If you think you’ve spotted the signs of subsidence in (or outside) your home, don’t worry.

How can you tell if a crack is subsidence?

The usual indications of subsidence are:

1. Cracks in the walls, ceilings and outside brickwork.
2. Expanding of existing cracks.
3. Cracks appearing after a long phase of dry weather.
4. Rippling of wallpaper that isn’t caused by damp.
5. Sticking of doors and windows suggesting doorframes or windowframes have changed shape.

Can a structural engineer check for subsidence?

If your mortgage lender has confirmed you have subsidence within their mortgage valuation then you will need to instruct a structural engineer or chartered building surveyor to complete a subsidence survey. The normal wording within the mortgage valuation that states this is: There is structural movement.

Is subsidence covered by insurance?

Most household insurance policies, and some commercial property insurance policies, cover loss or damage caused by subsidence, heave and landslip. They usually cover the cost of repairing the loss or damage and not the cost of preventing further subsidence.





Does subsidence devalue property?

How much does subsidence devalue a property? The level of severity will determine how much subsidence devalues a property, but generally speaking, you could find that it decreases the market value of your home by as much as 20%.

Who investigates subsidence?

Andrew Dust Structural Engineers – Subsidence Investigation – Structural Engineer.

Does subsidence stop on its own?

It can take many years for subsidence to show any effects on your house. Unfortunately, it is difficult to prevent subsidence, especially if it is based on the soil type beneath your house.

Is structural movement the same as subsidence?

WHAT IS STRUCTURAL MOVEMENT? Subsidence, settlement, heave, sway, bouncy floors, bulging walls, cracks, expansion and contraction are all forms of structural movement. Such movement occurs all the time, and usually its magnitude is so small it passes unnoticed.

Where do subsidence cracks appear?

Cracks caused by subsidence are normally of a diagonal nature and will suddenly appear in plaster work inside the building and on brickwork outside. They will usually be thicker than fine hairline cracks, which may be caused by natural movement of a structure, and tend to be wider at the top.





What happens if your house has subsidence?

Subsidence is when the ground beneath your house starts to sink. This causes parts of your house to sink, too, creating misaligned walls, cracks, and damage to the building.

Is ground movement the same as subsidence?

Subsidence is just one of the types of ground movement beneath a property, but there are others including settlement, heave and landslip.

What causes ground movement?

Ground movements can arise from two major sources: movements due to ground instability, caused, for example, by slope instability, geological voids, or subsidence due to the collapse of old mineworks; and movements due to a changing stress-state, leading to volume changes within the soil.

Can trees cause subsidence?

Can trees cause subsidence? Yes. When tree roots enter a shrinkable, clay soil, they can take up sufficient moisture to cause the clay to dry and shrink. As a result, any foundation built upon the clay may move or subside.





Can leaking gutters cause subsidence?

Leaking drains can cause subsidence and is one of the most common sources. Drains are designed to take water into the ground beneath your property, so any leaks in your drainage pipes will send water into the areas you don’t want it to be- underneath your home.

What should I do before ground subsidence?

How to prevent subsidence

1. Remove trees and bushes planted near the house. …
2. If you cannot remove the trees, maintain them with regular pruning. …
3. Carry out regular inspections of your property, paying particular attention to pipework, gutters and drainage systems in case of leaks and/or blocks.