A structural engineer’s report is usually requested by a mortgage lender or insurer when there is some indication that a property may have a structural problem that could affect its safety, value, or future repair costs. This report is usually produced by an accredited structural engineering consultancy.
Usually, the process starts with a valuation or home survey.
The surveyor is not there to fully diagnose structural problems. Their job is to identify risk indicators. If they see something concerning, they often recommend a structural engineer’s inspection. Typical wording might be:
“Evidence of possible movement noted. We recommend further investigation by a structural engineer.”
For mortgage lenders, the concern is mainly financial. The property acts as security for the loan, so the lender needs confidence that it is structurally sound and will remain marketable in the future.
So, if a survey reveals large cracks, sloping floors, distorted walls, roof sagging, or evidence of previous structural alterations, the lender may pause the mortgage application until a structural engineer has inspected the building. The engineer’s role is to determine whether the issue is cosmetic, historic, or evidence of an active structural defect.
One of the most common triggers is suspected subsidence. This occurs when the ground beneath part of the building moves unevenly, causing stress within the structure.
Typical signs include diagonal cracking around windows and doors, sticking doors, uneven floors, or gaps forming between walls and ceilings. However, not all movement is serious. Older buildings often show signs of historic settlement that may have stabilised decades ago.
A structural engineer’s report helps distinguish between harmless historic movement and ongoing structural failure, and that distinction can make the difference between a lender approving or declining a mortgage.
Lenders are also cautious where structural alterations have been carried out. Open-plan renovations, removed chimney breasts, loft conversions, and extensions can all affect the way loads are distributed through a building.
If there is no clear evidence that beams or supports were correctly installed, a lender may ask for a structural report to confirm the work was done safely. In many cases the engineer concludes that the structure is performing adequately, which reassures both the lender and the buyer.
Roof structures are another area of concern, particularly in older properties. Bowing walls, sagging rooflines, or spreading roof timbers can indicate that the roof is exerting pressure on the building over time.
Again, the key question is whether the movement is ongoing and dangerous, or simply part of the building’s age-related behaviour. A structural engineer assesses the severity of the issue and recommends whether repairs, monitoring, or no action at all are required.
Insurers look at structural reports from a slightly different perspective. Their concern is future risk and the likelihood of expensive claims.
Subsidence claims in particular can become very costly, so insurers often require engineering evidence before agreeing to cover repairs or continue insurance on a property with a history of movement. If a house has previously been underpinned, insurers may want confirmation that the repairs were successful and that no ongoing movement is occurring. Some insurers will also request reports after floods, fires, storms, or impacts to determine whether the building remains structurally safe.
The outcome of a structural engineer’s report can vary widely. In many cases, the report is reassuring and simply confirms that visible cracks or movement are longstanding and non-progressive. That often allows a mortgage or insurance policy to proceed normally. Sometimes the engineer recommends monitoring over several months to check whether movement is continuing.
In more serious situations, repairs such as underpinning, drainage improvements, roof strengthening, or additional steel supports may be necessary before a lender or insurer is satisfied.
Importantly, a structural engineer’s report does not automatically mean a property is unsafe or a bad purchase. Surveyors tend to be cautious, and lenders are naturally risk-averse. The report is there to replace uncertainty with professional evidence. Quite often, what initially appears a concern, turns out to be a manageable or historic issue once properly assessed by a qualified chartered structural engineer, typically someone associated with organisations such as the Institution of Structural Engineers or the Institution of Civil Engineers.