There are different types of foundation cracks namely vertical, diagonal, horizontal, and step cracks. Each of these needs to be identified before proceeding with repairing them. Here is how to identify and repair each of them:
Vertical: Vertical cracks are a common occurrence and can be found in almost every house. These cracks run up and down. They are typically formed in two to three years of construction when concrete sets and shrinks cracking under tension. While these cracks do not signify structural damage, they may lead to water seepage into the foundation which can cause significant problems over time. Vertical cracks, however, are easy and affordable to fix. The best solution to repairing vertical cracks is to use epoxy or urethane injections. These materials are injected into the cracks through holes drilled from inside the house, typically a basement. Following this, a sealing material is injected to close the cracks. This material is flexible which guarantees that the crack does not open up if the foundation undergoes settlement in the future.
Diagonal: These cracks run at 30 to 75 degrees from the vertical of the wall and are formed due to uneven foundation settlement. When one corner of the house settles it puts the house under a combination of vertical and horizontal tension giving rise to diagonal cracks. Due to this uneven foundation settling, the cracks are wider at one end and narrower at the other. The wider end of the crack points to the precise area of the house that has settled down. The occurrence of these cracks also calls for house owners to inspect the causes and extent of settlement with expert help from expert foundation repair inspectors.
Horizontal: The cracks that run sideways are dangerous ones as they indicate structural damage. Brick and concrete block foundations are more prone to developing horizontal cracks. These cracks occur as a result of a bowing foundation. The causes that can cause a foundation to bow are:
- A back filling of dirt and gravel is used to fill the exterior of the foundation wall. If it is filled improperly or undergoes over compression or is not properly drained then it can cause foundation to bow inwards.
- Excessive rains followed by snow or freezing can increase the hydrostatic pressure inside the soil and cause the foundation wall to bow inwards.
This is a serious issue which warrants immediate action to be taken by homeowners as bowing foundations can lead to structural failure and culminate in collapsing of the house. There are numerous ways in which horizontal cracks can be dealt with. Using high-strength strapping on the inside of the foundation or reinforcing the basement or crawl space with braces are some of the common methods use to prevent foundation from further bowing inside and developing cracks. However, these cracks require expert evaluation. The procedure finalized by the structural engineer should be followed to correct the problem.
Step Cracks: There severity varies depending on the nature of the cracks. Like diagonal cracks, these cracks are caused due to differential settling of the foundation. Mostly common in brick and concrete blocks, the cracks appear on the exterior wall of the foundation. If the cracks only exist between brick and mortar then it means that the foundation problem is not serious and the cracks can be repaired by repointing mortar. However, if bricks seem to be moved in or out of its place then the crack may signify structural damage. Step cracks are treated in the same way as diagonal cracks. However, you should always bring in expert help to evaluate and analyse the severity of these cracks.