Concerns about a property can arise because of cracking, uneven floors, sticking doors or windows, signs of movement, planned alterations or a proposed purchase. A structural survey provides an independent engineering assessment of the visible structural condition of the building.
Introduction
Some defects form part of the normal ageing and movement of a building, while others may require further investigation. Without professional advice, it can be difficult to judge the significance of what is visible.
One of the key roles of a structural engineer is to distinguish between normal building behaviour and defects that may affect structural performance. A survey or specific structural inspection can therefore provide valuable insight before important property or construction decisions are made.
What Is a Structural Survey?
A structural survey is a detailed visual inspection carried out by a qualified structural engineer to assess the structural condition of a building. It focuses on the elements that support the building and transfer loads safely to the foundations.
During the inspection, attention may be given to:
- Foundations where visible
- Load-bearing walls
- Floors and supporting floor structures
- Roof structures
- Steel beams and lintels
- Chimneys
- Areas showing signs of movement
- Evidence of settlement or possible subsidence
Observations are considered alongside the age, construction and layout of the building. As the assessment is visual, concealed elements behind finishes, beneath floors or within walls cannot normally be inspected without intrusive work.
When Might You Need a Structural Survey or Inspection?
Not every concern requires a comprehensive survey. Where the concern relates to one particular part of the property, a specific structural inspection may provide the appropriate level of engineering advice.
Common reasons for seeking an assessment include:
- Visible cracks in internal or external walls
- Uneven or sloping floors
- Doors or windows that stick or no longer close correctly
- Signs of structural movement
- Chimney breast removals
- Load-bearing wall alterations
- Loft conversions or extensions
- Sagging or distorted roof timbers
- Previous structural alterations requiring assessment
- Professional advice before renovation or construction work
Visible defects do not automatically indicate a serious structural problem. Minor cracking and movement can develop as materials expand, contract and age. The purpose of the inspection is to assess the likely significance of the observations and recommend further action where appropriate.
How Is a Structural Survey Carried Out?
The assessment begins with a systematic visual inspection of safely accessible parts of the property. External and internal observations are considered together so the engineer can form an overall view of the building's behaviour.
External Assessment
The external inspection may include:
- Brickwork and masonry
- Cracking patterns and their location
- Roof line alignment
- Chimney condition
- Lintels above openings
- External walls
- Ground levels around the building
- Visible drainage arrangements
- Trees and vegetation that may influence ground conditions
Internal Assessment
The internal inspection may include:
- Internal walls
- Floors and supporting structures
- Ceilings
- Roof timbers and loft spaces where accessible
- Steel beams and structural supports
- Chimney breasts
- Areas affected by previous structural alterations
What Does a Structural Engineer Look For?
The engineer considers how the building performs as a whole rather than treating individual defects in isolation.
Attention may be given to:
- Cracking within masonry, brickwork or plaster
- Signs of structural movement
- Uneven or sloping floors
- Deflection within roof structures
- Distortion or bowing of walls
- Previous structural alterations
- Steel beams and structural supports
- Visible timber deterioration
- Moisture affecting structural elements
- Evidence of foundation movement or settlement
Relatively minor-looking defects can sometimes be significant when viewed alongside other observations, while more noticeable cracking may be historic and stable. Conclusions are therefore based on the overall structural behaviour of the building.
Understanding Structural Movement
All buildings experience some movement throughout their lifetime. Materials expand and contract with temperature and moisture changes, and foundations may experience small seasonal movements caused by variations in the ground.
When assessing movement, the engineer considers:
- The location, pattern, width and direction of cracking
- Whether movement appears historic or recent
- The relationship between internal and external observations
- The age and construction of the building
- Previous structural alterations
- Local ground conditions
- Nearby trees and visible drainage arrangements where relevant
Where movement appears historic and consistent with the property, remedial action may not be required. Where movement may be progressive, further investigation or monitoring may be recommended.
Settlement and Subsidence
Settlement usually occurs during the early life of a building as foundations adjust to the supporting ground. Once the building stabilises, further movement is normally limited.
Subsidence occurs when the supporting ground beneath part of a building moves downward relative to the surrounding ground, leading to differential movement. Possible contributing factors can include changes in soil moisture, tree roots, defective drainage, variable ground conditions and historic mining activity.
Cracking alone does not confirm subsidence. Where appropriate, drainage surveys, crack monitoring or specialist ground investigations may be recommended before the cause can be confirmed.
What Happens After the Survey?
Following the inspection, the engineer prepares a report summarising the observations and providing practical recommendations where appropriate.
The report may include:
- A description of the property
- The scope and limitations of the inspection
- Structural observations
- Photographic evidence
- An engineering assessment of identified defects
- Recommendations for remedial works where appropriate
- Advice about further investigations
Where structural alterations are proposed, separate structural calculations and drawings may also be prepared to support Building Regulations approval.
Frequently Asked Questions
How long does a structural survey take?
The time depends on the size, age and complexity of the property. Many residential surveys and specific inspections take between one and three hours, although larger or more complex buildings may take longer.
Can a structural survey identify subsidence?
A survey can identify signs that may be consistent with subsidence, but subsidence should not be assumed solely because cracking is visible. Further investigations may sometimes be required before the cause is confirmed.
Do all cracks require a structural survey?
No. Many cracks develop because of normal settlement or material movement. Advice is recommended where cracks appear significant, continue to worsen or occur alongside other signs of movement.
What happens if structural defects are identified?
The report will explain the observations, likely cause where this can reasonably be determined, whether movement appears historic or ongoing, and any recommended remedial work or further investigation.
Do I need an inspection before structural alterations?
Early engineering advice is recommended before removing load-bearing walls, chimney breasts, altering roofs or carrying out other structural work.
Can older properties be structurally surveyed?
Yes. The engineer considers the age, construction methods and current condition of the building when distinguishing normal ageing from defects that may require further investigation.
Conclusion
A structural survey or specific structural inspection provides an independent assessment of the visible structural elements of a building. It can help clarify the significance of cracking, movement, previous alterations and other concerns.
Every property should be considered in the context of its age, construction and overall condition. A balanced engineering assessment helps property owners and professionals make informed decisions with confidence.
Discuss Your Property Concerns With an Engineer
PS Structural Ltd provides structural surveys, specific structural inspections, engineering reports and structural calculations for homeowners, buyers, landlords, architects and developers.