The presence of cracks in your home, whether new or old, is not an uncommon phenomenon. However, it is crucial to monitor these signs of deformation, as they can sometimes worsen and lead to serious consequences. This comprehensive guide covers the different types of cracks, their potential causes, and the steps to follow to carry out proper repairs and obtain compensation from your home insurance.
Cracks in houses: a common problem
Cracks appear as cracks or splits, affecting the walls, ceilings, or even the floor of a building, whether indoors or outdoors. Over time, movement of soils and building structures is inevitable, often causing the appearance of cracks. While the majority of these are benign, some can pose a real danger and require urgent repairs.
It is essential to monitor all cracks, regardless of their size. A small crack, if left unattended, can develop into a more serious one, causing water infiltration and compromising the stability of your home’s foundation.

The Origins of Cracks
Cracks can have many causes, whether they are slight, deep, or visible indoors or outdoors. The main contributing factors include:
- Water infiltration: Periods of rain followed by freezing temperatures can aggravate cracks. Water can seep in and, when it freezes, expand, widening the crack.
- Shock: Storms, natural disasters, or accidents can cause damage and cracks.
- Drought: Prolonged periods of drought can also cause cracks due to soil shrinkage.
- Soil Movement: Landslides or subsidence can cause cracks in buildings.
- Construction Defects: Poor quality foundations or masonry can also cause cracks.
Pay special attention to clay soils, as they expand under the influence of water and then contract during high temperatures, leading to significant ground movements that can cause cracks.
Crack Typology
Cracks can vary in severity. To classify them, we generally look at the size of the gap between the edges of the crack. There are three main categories:
- Microcracks: Below 0.2 mm, these are often superficial and do not seriously impact foundations. Fine cracks:
- Measuring between 0.2 mm and 2 mm, these are generally the result of impacts or foundation movement. Deep cracks:
- Exceeding 2 mm, these cracks can be dangerous and require rapid professional intervention. Discover the different solutions for repairing cracked glass, whether for windows, mirrors, or other glass objects. Learn how to assess the damage and choose the best method to restore the clarity and safety of your glass surfaces.

Generally caused by an incorrect mix of sealant, these do not pose an immediate threat to structures. However, if they occur with movement behind the wall, they could indicate underlying leaks.
Fine cracks
Often caused by impacts, these cracks can appear in several configurations: horizontal, vertical, stepped, or whiskered around openings. Although they are usually harmless, any extension deserves expert examination.
Deep Cracks and Fissures
With an amplitude greater than 2 mm, these indicate serious problems such as soil settlement or fragile foundations. They must be treated quickly to prevent water infiltration or structural collapse.
Assessing Cracks: Inert or Active?
Cracks are not static; some evolve over time. It is therefore crucial to monitor their development using a small plaster marker. Two categories can be distinguished:
Inert Cracks:
- These become stable over time and can often be treated with simple filling. Active Cracks:
- These cracks tend to widen; their development requires professional intervention. https://www.youtube.com/watch?v=fwInfs7g2KI Warning Signs to Watch For
Rapid propagation of cracks.
Suspicious creaking heard in the house.
- Water infiltration or moisture problems observed.
- Visible damage: shifting tiles, unaligned slabs, or crumbling plaster.
- Crack Repair
- If you notice cracks in your home, it is imperative to assess their extent before undertaking any repairs. Here’s how to proceed depending on the type of house:
New Home
If you live in a recently built house and cracks appear, report them immediately upon completion of the work. Send a registered letter to the builder detailing the cracks, specifying their size and location, and attaching photographs.
Three guarantees can cover you:
Perfect Completion Guarantee:
Valid for one year after completion, this guarantee covers all defects.
- Ten-Year Guarantee: Covers damage affecting the strength ten years after completion.
- Building Damage Guarantee: Allows you to receive compensation quickly without waiting for a court decision and can be claimed alongside the ten-year guarantee.
- Discover effective solutions for repairing cracked glass, whether for your windows, mirrors, or any other glass object. Learn how to revive your glass surfaces and preserve their beauty. Old House

Insurance: Understanding the Compensation Procedures
Cracks can appear in your home during landslides or natural disasters. Most home insurance policies cover these cases through specific coverage. To file a claim:
Make sure your property is located in an area declared a natural disaster area by decree.
Submit a claim to your insurer within 10 days of the decree’s publication in the Official Journal.
- Report cracks to the town hall
- To receive compensation, it is vital that the municipality supports your claim. You can go to the town hall to formalize this process, making your situation more official and potentially speeding up the compensation process. Be prepared to wait up to six months for a response from the administration.
https://www.youtube.com/watch?v=GlmHRKpUCPQ
Repairing Cracks: Steps to Follow
Clean the crack thoroughly.
Spread the edges using a suitable tool.
- Sand the crack, then dust it off.
- Wet the crack and apply filler.
- Let it dry, then sand it again for a smooth finish.
- To ensure the safety of your home, it is always advisable to call in professionals, especially for deep or active cracks to avoid any risk to the structure. Crack Repair Costs
- The costs associated with crack repair vary considerably. Before beginning, an assessment by a professional is necessary to determine the severity of the cracks. On average, the cost for an assessment ranges between €600 and €1,000 and depends on several criteria, such as the size of the house, the number of cracks, and the type of expert chosen.
Type of Repair
Average Cost
Ready-to-use facade coating
| Between €3 and €16/kg | Mixable coating powder |
|---|---|
| Between €1 and €11/kg | Slight cracks by a professional |
| Between €15 and €20/m² | Foundation cracks by a professional |
| Between €3,000 and €30,000 | FAQ |
| How do I know if a crack is serious? Cracks wider than 2 mm, that spread rapidly, or are accompanied by cracking, should be assessed by a professional. | What should I do if I buy a house and discover cracks? |
Report them immediately to the seller. If they are not mentioned, you may be covered by a “hidden defects” warranty.
Does my home insurance cover cracks?
Yes, but only if a natural disaster has been declared. Check the terms of your policy carefully.
How long does crack repair take?
The time depends on the severity of the cracks and the work to be undertaken, but it is recommended to allow several days for a complete repair.
Can I repair superficial cracks myself?
Yes, for minor cracks, you can consider a DIY repair. However, for deeper cracks, calling a professional is recommended.

