One of the most common causes of cracking during UK heatwaves is the effect of drying soil on your home’s foundation.
Much of the UK, particularly in the South East, sits on clay-heavy soil. During a heatwave, this soil loses moisture rapidly, causing it to contract and shrink. As the ground beneath a property shifts, it can place stress on the foundations, resulting in visible cracks in walls, floors, or ceilings.
When the soil around a home shrinks unevenly, it can lead to foundation movement or settlement, a condition known as subsidence. Cracks caused by subsidence are often diagonal and wider than a few millimetres. Left untreated, this can lead to more serious structural issues, which are costly and complex to fix.
Prolonged heat affects not just the ground beneath us, but the materials our homes are built from. Expansion and contraction can create visible damage indoors and out.
As temperatures rise, materials like brick, concrete, and plaster expand. When this expansion meets resistance or occurs unevenly across a structure, the stress has to be released somewhere—typically in the form of cracking. This is especially common in external walls that receive prolonged sun exposure.
Thermal expansion cracks often appear in predictable places—such as around window frames, doorways, or where two walls meet. Ceiling junctions, especially in older homes, can also develop fine fissures. These cracks may be superficial, but if they widen over time or reappear after repair, further investigation is recommended.
Not all cracks are created equal. Understanding the difference between harmless surface cracks and those that signal deeper issues is essential.
Hairline cracks, often less than 1mm wide, can be caused by drying plaster or slight thermal movement and are usually cosmetic. Structural cracks, however, tend to be wider, longer, and more irregular—often signalling movement in the foundation or structural stress within the building.
The location of a crack can be just as important as its size. Certain areas of the home are more prone to movement and should be monitored closely.
Openings such as windows and doors are natural weak points in a building's structure. Cracks that radiate diagonally from these corners may indicate foundation movement or thermal stress and should be assessed for progression.
Diagonal or stepped cracks running through plaster or brickwork inside the home can be a red flag for subsidence or uneven settlement. These cracks often require expert assessment to determine whether structural repairs are needed.
While some cracks are simply cosmetic, others could indicate serious structural issues. Spotting the warning signs early can prevent further damage.
If cracks begin to widen over time, appear suddenly, or are accompanied by sticking doors and sloping floors, they may signal foundation movement or subsidence. These symptoms should never be ignored, especially following extreme weather like heatwaves.
If you're unsure whether the cracks in your home are a cause for concern, it’s wise to seek expert advice. Acting quickly can save you time, money, and stress.
A chartered surveyor can assess the severity of the cracking and provide a report. If structural movement is suspected, they may refer you to a structural engineer, who can conduct a more detailed investigation and recommend any necessary repairs or reinforcements.
Not all cracks are cause for alarm. In many cases, especially after a heatwave, small cosmetic cracks can be safely repaired without major intervention.
Hairline cracks in plaster or paintwork that don’t widen over time can usually be filled with a flexible filler and repainted. Make sure the area is dry and stable before applying any cosmetic repairs.
If your home is experiencing recurring or worsening cracking, long-term solutions may be required to stabilise the structure and prevent future damage.
Maintaining consistent moisture levels in the soil around your foundation is key. Installing a soaker hose system, improving drainage, or planting water-efficient landscaping can help prevent soil shrinkage and expansion.
For homes with serious foundation movement, structural repairs such as underpinning may be necessary. This involves strengthening the foundation to prevent further subsidence and is typically advised following a surveyor or structural engineer’s assessment.
Trees and large shrubs near your property can absorb significant amounts of water from the soil during hot weather, leading to soil shrinkage and potential subsidence. Maintain an appropriate distance between large trees and your home, and consider root barrier systems where necessary.
Modern materials are designed to handle the stresses of expanding and contracting with temperature changes. Flexible render, breathable plaster, and expansion joints in brickwork can help prevent heat-related cracking over time.
Inspect your property regularly during hot spells. Look for early signs of cracking around doors, windows, and external walls. Prompt action can prevent minor issues from developing into structural problems.
If you're noticing cracks or signs of movement in your home, CATH Services offers honest, professional guidance tailored to your specific property. We assess the situation thoroughly and help you understand whether it's cosmetic or structural.
From minor crack repairs to full structural interventions, our experienced team provides reliable workmanship using proven materials and methods. We can also advise on long-term solutions like drainage improvements or root management.
Based in the South East, we're proud to support homeowners with dependable service and clear communication. Whether you're looking for peace of mind or practical repair work, CATH Services is here to help—no jargon, no pressure.
At CATH Services, we provide a complete range of building and property improvement solutions for homeowners across Surrey, Hampshire and West Sussex. Our experienced team is committed to delivering exceptional craftsmanship, reliable service and results that transform your home. Here’s an overview of the services we offer.
There are countless reasons to choose CATH Services, but most importantly is our customer-focused approached that combines excellent workmanship with honesty and integrity
Public liability insurance up to 5 million pounds.
We have no hidden costs, so the price you're quoted is the price you'll pay.
We pride ourselves on ensuring that every client is left happy.
We use the very latest in equipment and have a fully trained team.
“CATH Services did an amazing job on our home extension. The team was professional, communicative, and delivered exactly what we envisioned. The attention to detail was outstanding, and they left everything spotless. Highly recommend!”
— Mark E
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— Samantha F
“Excellent service from start to finish. The team transformed our outdated bathroom into a modern space that looks incredible. They were polite, efficient, and kept disruption to a minimum. I wouldn’t hesitate to recommend them!”
— David S
“CATH Services recently renovated our entire ground floor, and we couldn't be happier. They provided expert advice, used high-quality materials, and finished ahead of schedule.”
— Elaine R
“Peter and Gary are conscientious and thorough. They have done a number of jobs for us over the last 18 months, all of which have been completed to a high standard. They always leave the place clean and tidy. I can definitely recommend them.”
— Gill Lowe
“I know my ratings seem too good to be true, but we genuinely cannot fault Cath Services work. Peter and Gary have been brilliant, it doesn't matter what challenge you throw at them, they seem to be able to handle it and produce an excellent result. I would recommend them to anyone and everyone.”
— Caryn C
“I have used Cath Services for different jobs during a couple of years, such as fencing, cleaning roof and paving, new paving, clear out overgrown part of garden, etc. They are always in time, work very hard and finish with the best quality and neatness. Would never ask someone else to help me around my house and will highly recommend them to family and friends.”
— Agneta
“This is the second time I’ve used Cath Services. The first was for internal alterations and a bathroom at a previous property. Peter and Adam have done another beautiful job with my two bathrooms this time. Their attention to detail, ideas for a better finish, and how they think through the job to ensure the best outcome is outstanding…”
— Emma E
“I'm based in Witley, and have now used Peter and the team at Cath Services Ltd for several years. They quickly became my trusted company for any work around the house or garden. They have done projects including a driveway, bathroom refurbishment, wooden flooring, decking, paving, gate installation, and more. The quality is outstanding and I've always been delighted with the outcome…”
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“I highly recommend Peter and his team for all job inside and outside the house. The quality of their performance is matching with the highest expectations. They are creative and helpful, having excellent ideas and don't know impossible. Do not hesitate to contact them if you need a professional help.”
— Melinda
“Peter and the team are our go-to for any outdoor work needed, be it fencing, landscaping, window or gutter cleaning. They do it all with the highest attention to detail, professionalism and skill. We’ll be seeing you soon again I’m sure guys!”
— Julia B
“Excellent company and delighted to recommend them. They arrive when they say they will and they get on with the job. Quality workmanship and attention to detail as well as being tidy.”
— Martin H
“They always do a great job, come on time and do windows. Often other little jobs too. Gutters and solar panels…”
— Jane DFind answers to common questions about our building and renovation services, how we work, and what to expect when you choose CATH Services. We’re here to help you plan your project with confidence and make informed decisions for your home.
We pride ourselves on reliability, fair pricing, and delivering every project with care and attention to your safety and satisfaction.
CATH Services supports homeowners and businesses across Surrey, Hampshire, and West Sussex. Whether you’re planning a renovation, extension, or general building work, we’re here to help – get in touch today.
Phone: 01483 663463
Email: info@cathservices.co.uk
Address: 25 Waverleigh Rd, Cranleigh GU6 8BZ
