Does a crack in the wall always mean subsidence?

Chocolate Box Cottage, Woburn Sands Grade II Listed

Buying a property is a major financial commitment, which is why you need to make sure that the building you have your eye on is in good condition before you exchange contracts. However, many building defects are simply not recognised by the untrained eye, which is why an independent surveyor can be a homebuyer’s most important ally. Take a crack in the wall for instance. Would you be able to tell if a crack was a minor cosmetic defect or an indication of a serious structural issue? Chances are you won’t know what to look for.

With a professional property survey and the help of an experienced building surveyor’s beady eye carrying out an in-depth visual inspection of all the building elements, on the other hand, you will know exactly what you’re dealing with. Armed with all the important facts, you are then able to make a reasoned and informed decision on how to proceed with your purchase.

At Alan Rance Surveyors, we have more than 30 years’ experience of surveying residential property in Hertfordshire, Bedfordshire and Buckinghamshire including homes in Leighton Buzzard, Dunstable and Tring. Our Building Surveys are detailed inspections, reporting on any defects found and advising on upkeep and maintenance and providing cost estimates for remedial action. And while we know that most surface cracks are usually nothing to worry about, cracks that are the result of structural movement can be very serious indeed. Let’s take a closer look.

How does a crack in the wall come about?

First off, let us reassure you that cracks in a wall of a house are by no means unusual. In fact, most properties have them at some point. Cracks can occur naturally as a result of settlement, such as is in the following situations:

  • The foundations of building extensions and new build properties may need time to settle under their own weight, leading to hairline cracks appearing in walls.
  • Recently plastered interior walls can also show hairline cracks as a result of the plaster drying out.
  • Temperature and humidity fluctuations in older properties lead to minor expansion and contraction with associated cracking, which is entirely normal.
  • UPVC double glazed window replacements may show cracking around the window if the original timber window did not have a supporting lintel.
  • Houses near busy roads could experience cracking as a result of ongoing road traffic vibration.

What causes subsidence cracks?

As mentioned above, most cracks are superficial, with painting and decorating all that’s required to deal with them. However, large cracks could be a sign of structural movement in the building’s foundations, which is a major issue and could ultimately lead to the building falling down.

Structural cracks can be the result of a number of causes including:

  • Tree roots

One of the biggest culprits causing subsidence are large trees planted too close to the house. If tree roots work their way under the building and absorb moisture there, they can destabilise the foundations and movement may occur. Willow, oak, ash and poplar are known to be particularly ‘thirsty’ species that should be planted at a minimum distance of 10 metres from the building.

  • Defective drains

If a leaky drain or a burst pipe lays undetected underground for long periods of time, the ground can become saturated and the subsoil may be washed away. In this scenario, the ground may no longer be able to properly support the building standing on it, and structural movement and damage to the building could occur as a result.

  • Prolonged dry spells

Did you know that home insurance claims for subsidence damage rose by 300% after the long, hot summer of 2018? Heatwaves and dry spells are especially dangerous for properties that were built on clay soil which shrinks and hardens when dry, pulling away from the foundations.

  • Heavy rainfall

Clay soil can absorb large quantities of water after rainfall, becoming heavy and sticky as it expands. Heavy rainfall and flooding can be particularly dangerous for homes built on clay-rich soil. In the UK, most subsidence is seasonal, involving shrinkage in the summer and expansion during wetter winter weather.

When does a crack indicate a structural issue?

The shape and width of a particular crack can be an important indicator of its severity in terms of structural movement. Tell-tale signs of subsidence cracks include cracks that

  • are more than 3mm thick
  • have appeared suddenly
  • run diagonally across a wall
  • are wider from top to bottom
  • occur around windows and doorways
  • cause rippling in wallpaper
  • are visible from inside and outside

What to do next?

If you are worried about the cracks in the wall of a property that you are interested in buying, we urge you to seek professional advice at the earliest opportunity. At Alan Rance, we’ve been surveying properties old and new for over 30 years and pride ourselves on providing honest, impartial in-depth advice to our clients. Get in touch to request a survey quotation today.

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Client Testimonials

Based on 21 reviews
Gareth Taylor
Gareth Taylor
Really comprehensive survey and produced quickly, would highly recommend.
Linda Cain
Linda Cain
Very happy with the Home Buyers Report carried out by Alan. We received the 119 page report and photos later the same day. Alan is very professional and is happily available to answer any questions you may have. We have just exchanged contracts and looking forward to moving in soon. We highly recommend Alan and wouldn’t use anyone else!
Abi Browning
Abi Browning
Really professional and efficient. We chose to employ Alan for our building survey and we were impressed with the speed and quality of his report. The advice given was invaluable to support the final decision and our renovation plans. Thanks for all your help Alan!
Mihail Marian
Mihail Marian
Alan carried out a level 3 homebuyers survey on a house we had an offer accepted on. It was very easy to get hold of him and he responded quickly to our emails. The report was very detailed and came very quickly (the same day when the survey was done). As FTB we had a lot of questions and Alan was very helpful answering our questions and explaining the details. Highly recommend!
Chris Barker
Chris Barker
Alan gave a swift and highly detailed survey and I would highly recommend his services.He is approachable and has a great depth of knowledge.
chris dawson
chris dawson
We used Alan for a home buyers survey "twice" !!! as our first purchase fell through at the last minute, nothing was too much trouble, communication before and after and an explanation of the very comprehensive report was superb. Would thoroughly recommend using Alan
Alan Rance Surveyors carried a full Building Survey on our prospective purchase and we are very pleased with the depth of the report and the level of service provided. Alan is very experienced and personable, and communication is excellent. He was very happy to respond to our follow-up questions, which he did very quickly. Definitely 5 stars. Thanks very much Alan!
Charlotte Rogers
Charlotte Rogers
Really great and communicative surveyor, would definitely recommend Alan.
Alan is brilliant at his job, punctual, reliable and explained the report to me would highly recommend great value for money
Chloe Radford
Chloe Radford
Great service, very trustworthy. Would highly recommend