Underpinning and Subsidence in London Homes

Daniel Nikolla

Oct 20

1 min read

Updated: 7 days ago

Cracks appear in many older homes and not all of them mean subsidence. Proper investigation avoids unnecessary and costly work.

This guide explains how subsidence is recognised, investigated and, where necessary, repaired.

Reading the signs

Diagonal cracks that taper, doors and windows that stick, and cracks that open and close with the seasons can indicate movement. Monitoring over several months shows whether it is ongoing.

Finding the cause

Clay shrinkage, leaking drains, tree roots and shallow foundations are common causes. Often, fixing the cause, such as a drain, stops the movement without major structural work.

Engineer's investigation

An engineer records crack patterns, checks the surroundings and may recommend crack monitoring, drain surveys or trial holes to see what is happening below ground.

When underpinning is needed

Underpinning takes foundations down to more stable ground. It is designed by an engineer, carried out in a controlled sequence, and normally needs Building Control approval.

Alternatives to underpinning

Depending on the cause, other options include removing or managing trees, repairing drains, or using other foundation strengthening methods. The right one depends on evidence, not assumption.

Talk to Graal

Planning work on your home or a small development? Graal Structural Engineering provides structural design and project management support across North London. Call 07737188754 or request a free quote through our contact form and we will tell you what is needed and what it is likely to involve.