Cracks in walls can be a major cause for concern, especially if you live in an older home. The thought of water damage or structural issues is frightening, but it’s also possible that your wall cracks are caused by something as simple as temperature changes. If you want to know why your walls keep cracking and what you can do about it, read on:

If you have a cracked wall in your home, the first thing that comes to mind is usually water damage.

Water damage is one of the most common causes of cracks in walls and can happen in several different ways:

  • Flooding from storms or natural disasters
  • Leaks from plumbing problems (running toilets) or roof leaks
  • Condensation buildup inside your home due to poor insulation or ventilation

If this is the case, the source of water infiltration must be found and rectified.  This can involve a roofer or other exterior contractor in the case of water penetrating from outside.  If it’s a plumbing issue, then a plumber needs to be called to locate and fix the leak.

Cracks from expanding and contracting materials.

Construction materials expand and contract with seasonal changes – they expand during warm weather and shrink during colder temperatures.  However, not all building materials expand and contract at the same rate, and that can be a problem.  Drywall/plaster expands and contracts at a different rate than wood, which expands and contracts at a different rate than metal, then tile and so on…  So wherever two different materials join, such as a door casing against a wall there’s a greater chance of cracking.  In these cases we use a very flexible caulking that can tolerate the normal shifting of the 2 materials without cracking.

Cracks from movement in the foundation or crawl space.

If you have cracks in your walls, it’s likely that they’re from movement in the foundation or crawl space. The most common cause of this kind of cracking is frost heave; this occurs when water freezes in the soil and expands, pushing up against your wall. Soil settling is another possibility for wall cracking–the ground under your house may settle due to erosion or shifting soil conditions, which could cause cracks to appear on your interior walls as well as exterior ones (if they’re exposed).

Cracks caused by high winds, earthquakes and construction.

If you live in an area where high winds are a common occurrence, cracks can be caused by the force of the wind. 

Cracks can also be caused by earthquakes.  In Toronto we don’t usually get many natural earthquakes, however we get a lot of man-made earthquakes called “construction”!  Whether it’s roadwork or building a condo these activities shake the ground and can cause cracks to show up in your walls.  In this case, it’s best to wait until the construction is over and then have us in to fix the cracks.


We hope that this article has helped you better understand the causes of cracks in drywall and plaster. Some of these causes are beyond our scope of expertise as painters, but we can always refer you to a reputable professional to help you out.  Once they have eliminated the cause of the cracks we can come in and make your walls look as good as new.