last updated October 21st, 2025
Ensuring a prospective home is structurally sound should be at the top of your checklist. In the UK where housing stock ranges from centuries-old cottages to modern new builds structural issues vary greatly in type and severity. Identifying these problems early can save you thousands in unexpected repair costs and ensure you’re making a sound investment. This guide outlines the key structural problems to look for, how to spot them during a viewing and when to call in professional help. On an older property you may find cracks that have formed years ago due to settlement; these may be 'stable' if they are not growing and can often be cleaned up using 'crack stitching Helical Bars'.
Structural problems can significantly impact the safety, longevity and value of a property. In extreme cases structural damage may lead to costly repairs or even make a house uninhabitable.
By identifying these issues before purchasing, you can:
UK properties particularly older ones are prone to certain structural problems due to the climate, building techniques and materials used. Here are some common issues to watch for.
Subsidence occurs when the ground beneath a property shifts causing parts of the building to sink. It’s a common issue in areas with clay soil such as London and the South East. Underpinning where concrete or similar products are injected into the weakened ground is often used to stop the problem.
Heave happens when a property is pushed up from the ground - it is caused as pressure increases expand the ground such as when clay takes in moisture and as it expands, it can only move up bringing everything with it. Directing water near a property or weather events that regularly increase the water in clay can be sources of the problem as well as tree removal - the tree would have acted as a sponge for moisture previously.
Lansdslip occurs when a property moves sideways - it can happen when a building is built on a hill or near a cliff for example. Sometimes the complete property on its foundations move - it is a serious problem
This describes when land (usually) gently moves down and often happens during the few years after a house is built - it differs from subsidence as it is often a less severe movement and cracks are contained and can be managed.
Weak or poorly constructed foundations can lead to uneven floors, leaning walls and other structural issues. Victorian houses have widely varying foundations - if you are buying to add an extension or add a floor space, a structural survey is a must.
The wet climate makes damp a commonissue, particularly in older properties. Rising damp which is a flow of water up from the ground into a wall, penetrating damp (water coming through a wall maybe from rain) and condensation can all lead to structural damage over time.
Roofs are subject to wear and tear from the weather. Broken tiles or slates, sagging rooflines and water ingress are all warning signs. Look out for blocked gutters which can cause water to splash against the wall at the roofline.
Not all cracks are a cause for concern, but some indicate serious structural issues. For instance, wide cracks that run diagonally or in a staircase pattern could signal movement or subsidence.
Timber beams and joists can suffer from woodworm or dry and wet rot which weaken their structural integrity.
External or internal walls that bulge outward(bulging) or inward(bowing) may indicate serious structural stress or foundation problems. Most walls are built using 2 separate 'leaves' (consider them as an 'inner' and 'outer wall') that are connected by wall ties (small pieces of metal or plastic that join or 'tie' together the leaves for stability).
Typical causes are:
Never attempt to repair a defective wall by yourself - it is dangerous and requires expert advice and repair.
When viewing a property it’s essential to keep an eye out for red flags that could indicate structural problems. Here’s a checklist of signs to look for.
Inspect the exterior walls for cracks especially around windows and doors and corners of rooms. Look for diagonal or stair-step cracks as these may indicate movement.
Stand back and examine the roofline. A sagging roof or missing tiles/slates may suggest structural damage.
Check that the chimney is straight and free from significant cracks. Loose or leaning chimneys can be dangerous. The 'crown' which is the very top of the chimney is exposed and prone to leaking. If a chimney has been removed at roof level check below it internally to see if the remaining internal chimney remains - if it has been removed, check that the outer wall has not moved - usually a chimney should not be 'structurally' supporting the building. Externally check the wall (if an external wall) where the chimney runs to the lower fireplace and look for cracking. If the internal chimney has been removed and the chimney above the roof is visible, check the attic to see if a steel 'gallows' bracket has been fitted to support it.
Poor drainage can cause water damage to the foundations. Look for pooling water, blocked gutters or downpipes that don’t lead away from the house.
Uneven gaps around frames or windows and doors or windows that don’t close properly may signal subsidence or movement.
If a structural wall has been removed a steel beam will usually have to be placed to give support to the walls and floors above the removed wall. This needs to be sized and installed correctly or there will be movement in the walls and floors above so always check above the beam for cracks and sloping floors.
Test the flooring by walking through each room. Uneven or sloping floors may indicate subsidence or foundation issues.
Look for discolouration, peeling wallpaper or a musty smell. Pay particular attention to basements, bathrooms and kitchens.
Stains or sagging areas in the ceiling may indicate water ingress, leaking pipes or roof issues. If there is an upstairs bathroom, try to work out where the waste pipes are - then go downstairs and check the ceiling in the room below for leaks.
In period properties inspect exposed timber beams for signs of rot or woodworm.
Not all cracks are created equal. Some are superficial, while others may indicate severe structural issues.
These are typically under 3mm wide and often caused by normal settling or plaster shrinkage. They are not usually a cause for concern.
Vertical cracks often occur due to natural settling and are less serious than diagonal cracks. If they widen over time they should be investigated.
Cracks that run diagonally or in a staircase pattern across brickwork are a red flag. They often indicate movement, subsidence, or shifting foundations.
Any crack wider than 5mm is considered significant and should be inspected by a structural engineer.
Damp is a common issue in UK homes and can weaken the structural integrity of a property if left untreated. There are three main types of damp to look out for:
Caused by moisture travelling upwards from the ground. Look for tide marks on walls, flaky plaster, and a musty smell.
Occurs when water seeps through walls or roofs due to leaks or poor drainage. Check for damp patches on walls or ceilings.
Caused by excess moisture in the air, it often appears as black mould on walls and windows. Persistent condensation can lead to structural problems over time.
A professional survey is the best way to identify structural issues before buying a home.
If you spot any of the following during a viewing, it’s worth calling in a professional to assess the problem.
Cracks larger than 5mm or those following a diagonal pattern.
Visible dips in the roofline.
External or internal walls that appear to bow outward.
Significant damp patches or black mould.
Uneven floors or doors / windows that won’t close properly or are jammed in position.
If a survey uncovers structural problems, you have a few options.
Older UK properties such as Victorian terraces or Georgian townhouses are more likely to have structural problems. Here’s how to minimise your risk.
Identifying structural problems before buying a home is crucial in avoiding costly surprises. By knowing what to look for, conducting thorough inspections and relying on professional surveys you can make an informed decision and protect your investment. A dream home should not turn into a financial nightmare. Take your time, do your research, and don’t hesitate to walk away if the problems outweigh the potential. In the UK housing market the right property is out there - it’s just a matter of finding it.
