Most homeowners ignore cracks in the exterior basement walls; a lot of people are afraid to call specialist since they think it will be costly. But these cracks are an issue that should not be ignored. Even seemingly-insignificant cracks can lead to bigger problems. Small cracks can let in insects, vermin and water. One crack additional and/or larger cracks and larger repair costs.

If attempts to patch the basement wall cracks fails, then the crack demands further attention.

Homeowners often find cracks long after they first occurred. Common locations for cracks in the exterior basement walls include: pipe penetrations, service holes, windows, tie rods, in the corners of the walls and ceiling, and along the basement walls.

If you suspect that the crack is active (meaning it is widening, spreading, or moving), continuous monitoring is highly recommended. Mark both ends of the crack with a pencil to monitor the length of the crack. Draw several alignment lines across the crack at several points – if these marks show up curved or twisted later it means the crack is shifting unevenly. Be sure to date all marks since this will help the foundation specialist to identify how quickly the problem is progressing.

Indoor Inspection

Houses settle over time, so slight unevenness in the floor is not generally considered a major issue. However, homeowners should be alert to other more significant warning signs such as:

  1.  Door fails to close or latch
  2. Cracks around doors and windows or where the wall meets the ceiling
  3. Cracks in vinyl or ceramic flooring that has been installed directly over a concrete floor (not recommended)
  4. Windows that will not close completely

These may occur all over the house and not just in the basement.

Exterior Inspection

Once cracks appear inside the house, particularly on the exterior basement walls, it is recommended that the exterior of the house to be inspected by homeowners.

Ensure each corner of foundation wall is straight by using a level or a piece of straight lumber.  Walls should be straight, both up and down and from side to side.

Any bulge or curve in foundation wall regardless of the foundation type (block or poured concrete) means the foundation has shifted or the soil around the foundation has changed causing excess lateral force on walls.

Inspection of Concrete Foundation

If the house has poured concrete foundation walls (not concrete block), a visual inspection of the concrete is recommended. Concrete should not appear to be chipped out or flaked at any location. If no flaws are found, gently tap a few places with a screwdriver – concrete should be strong enough not to be damaged by a screwdriver. If the concrete crumbles or large pieces come out, this is an indication of a serious problem.

The reason for the concrete deterioration might be due to deficient concrete in the original construction or a progressing foundation problem.

Inspection of other Structural Components

Beside the foundation walls, there are other structural components that contribute to the structural integrity of a house. Therefore, posts and beams in the basement (or crawlspace) should also be inspected.

Posts should be straight and securely connected to the beams they are supporting. The bottom of the posts should be firmly connected to the base plates.

Wooden posts and beams should be inspected for dampness and rot. Discolouration of the wood could be a sign of dampness or rot. To test, scratch the discoloured areas with a screw driver; if the wood is soft or breaks apart, this likely indicates that the wood is rotting.

Any signs of moisture in the basement or crawl space may indicate poor perimeter drainage. Ensure that gutters are clean and downspouts are directed away from the house. In order to drain away any surface water, the ground around the house should be graded at minimum 5% slope away from the foundation walls.

Parts 2 and 3 of this series will discuss the different types of foundation wall cracks as well as what causes them. Additional details are available upon request. Please contact us at 647-343-0915 or by email at or