Surveys and inspections: what is being looked at

The distinction that catches people out

If money is being borrowed, the lender will arrange an inspection. It is easy to assume this is a survey. It is not. Its purpose is to satisfy the lender that the property is worth enough and is conventional enough to serve as security for the loan. It may take twenty minutes, it may be partly desk-based, and the buyer often never sees the full document. A property can pass that inspection comfortably while carrying defects that will cost a great deal to put right, because those defects do not threaten the lender's position.

An independent survey is a different transaction entirely. You commission it, you choose its depth, the surveyor's duty is to you, and its output is a description of condition and consequence rather than a number.

Choosing a level

The right level depends on the building rather than the budget. A conventionally built house of recent decades, apparently well maintained and unaltered, is reasonably served by a mid-level survey. An older building, one with solid walls, one that has been extended or converted, one with a complicated roof, one that has stood empty, or one where something already looks wrong, warrants a full building survey. The extra cost is small relative to the sums involved, and the report is correspondingly more useful because it discusses causes rather than only listing symptoms.

It is worth speaking to the surveyor before the inspection and telling them what you have noticed and what you intend to do with the building. A surveyor who knows you plan to remove a wall or convert a roof will look at different things.

What a surveyor can and cannot see

Most surveys are non-intrusive. The surveyor does not lift fitted floors, open up walls, take down ceilings or dismantle anything. They inspect what is visible and accessible, use instruments where appropriate, and infer from evidence. This is why reports contain careful language about areas that could not be inspected: it is not evasion, it is an accurate statement of the limits of a visual inspection. When a report recommends opening up or a specialist investigation, that recommendation is the most important sentence in it.

Movement, and how to think about cracks

Almost every building has cracks, and almost all of them are unimportant. Buildings settle in their first years, materials expand and contract with heat and moisture, and plaster cracks where two materials meet. What a surveyor is assessing is pattern, width, location and whether movement is historic or continuing. Diagonal cracking stepping through mortar joints near openings, cracks wider at one end, doors and windows out of square, and cracking that reappears after being filled are the things that prompt further investigation.

The word subsidence causes more alarm than it should. It describes downward movement of the ground beneath a foundation, most often associated with shrinkable clay soils, nearby trees, or leaking drains softening the ground. Many cases are resolved by removing the cause rather than by underpinning, and many buildings show long-stable historic movement that requires nothing at all. What matters is establishing whether it is active.

Water: the recurring theme

Most serious building defects are ultimately about water getting somewhere it should not be, or not leaving somewhere it should. Reports distinguish between penetrating damp, where water crosses the fabric from outside through a defect such as failed pointing, a blocked gutter, a cracked render or a bridged cavity; rising damp, where moisture is drawn up from the ground where a barrier is absent, bridged or damaged; and condensation, where warm moist air meets cold surfaces in a building that is insufficiently ventilated or unevenly heated.

They are frequently confused, and the distinction matters because the remedies are entirely different and only one of them is expensive. Condensation is by a wide margin the most common, and it is a heating and ventilation problem rather than a structural one. A report that identifies a damp pattern without proposing a cause has not finished the job.

Roofs, drainage and services

Roof coverings have finite lives, and a surveyor will comment on age, slipped or broken units, the state of flashings around abutments and chimneys, and whether the structure below shows deflection or past repair. Flat roofs attract particular attention because their failure modes are less visible and their lives shorter.

Drainage is often the least glamorous and most expensive discovery. Shared drains, drains crossing neighbouring land, historic clay runs disturbed by tree roots, and surface water with nowhere to go all produce problems that are invisible on a viewing. Where a property sits below the level of the road, or where the ground falls toward the building, the report will usually recommend looking further.

Electrical installations, heating, and gas or oil appliances are generally outside a general survey's scope beyond noting apparent age and any obvious concern, with a recommendation to have them tested by the appropriate specialist. Where an installation looks its age, that testing is worth doing before commitment rather than after.

Reading the report

Reports use a rating system, and the ratings matter more than the prose around them. Read every item at the highest rating first, then the recommendations for further investigation, then the summary. Convert each significant item into a question: what does this cost to put right, how urgent is it, and does it change what I am prepared to pay. A surveyor will usually discuss the report by telephone, and that conversation is where the material judgements get made, because it is where you can ask what worried them and what did not.

Finally, keep it. A survey is a dated record of a building's condition, and years later it is the only objective account of what a crack looked like or how old a roof was when you arrived.