A typical home weighs between 200 and 275 pounds per square foot, not including its foundation. Your home’s concrete and block foundation has a big responsibility supporting that kind of weight. It’s little wonder that sometimes it can show signs of stress in the form of visible cracks.
Noticing cracks in the foundation, whether casually or during a home inspection, doesn’t necessarily mean your home is in danger of toppling. However, in some cases, the problem can be severe and requires immediate attention. Knowing how and why foundation cracks form and what you can do about them is crucial in determining the next steps when they appear.
Why Do Foundations Crack?
House foundations crack for several reasons. The cause often determines the necessary repair method, if repairs are needed at all.
Construction Procedures
The foundation’s construction can sometimes be at fault. Soil that wasn’t adequately compacted before pouring can compress under the structure’s weight and leave the foundation without support. The cracks that result vary in severity, and the repair can be simple or complex.
Other construction issues that can cause severe cracking include undersized foundation footings and weak or improperly mixed concrete. Minor, typically benign, cracks can appear during concrete or mortar curing.
Settling Foundation
Even if the foundation was installed using proper techniques, the ground under and near the concrete could naturally shift over time. Water erosion and soil creep on a hill can displace soil material and leave sections of your foundation unsupported.
Various types of cracks can form when the foundation settles into the void created by displaced soil. The severity of the situation will determine the best repair solution.
Groundwater Pressure Issue
Cracks of varying severity can appear in foundations of any age if the inward groundwater pressure on the structure changes. The changes can happen when the ground becomes excessively dry or wet, causing the soil to contract or expand.
Tree roots, erosion, droughts, floods, poor drainage, frost heave or any other significant change to the soil’s environment can produce foundation cracks.
Often, groundwater pressure issues create the most severe foundation cracks that require immediate repairs to stop the problem from worsening.
Types of Foundation Cracks
Foundation cracks are a scary sight for any homeowner. Although you should investigate any cracks in your home’s foundation, not all of them are signs of imminent danger.
Hairline Foundation Cracks
Thin uniform or hairline cracks are the most common. Typically, these are harmless and can form days or weeks after a new foundation is installed. Hairline cracks are often a result of the concrete or mortar drying out as it cures. In older homes, hairline cracks can appear as a sign of concrete aging and are also not cause for alarm.
However, if small cracks turn into significant gaps or start allowing groundwater or rainwater to seep into the basement or crawlspace, it’s time for a deeper inspection to determine if they threaten the foundation’s integrity.
Vertical Foundation Cracks
Finding thin vertical cracks, regardless of their length, is usually nothing to worry about unless they leak water, increase in width, are numerous or include wall bowing. Typically, this type of crack results from minor groundwater pressure changes from soil contraction and expansion.
If the crack becomes wider than the thickness of a coin, it’s time to call for professional assessment and repair.
Diagonal Foundation Cracks
Foundation cracks that form diagonally in concrete or through block faces signify a settling foundation. Settling can occur in new or old homes due to changing ground conditions that likely require mitigation to avoid further damage. These cracks need a professional assessment to determine if they need repair or aren’t concerning.
Horizontal Foundation Cracks
Horizontal foundation cracks of any length or thickness are a serious cause for concern, especially if accompanied by wall bowing. Significant, detrimental groundwater and soil pressure typically cause these cracks. Severe temperature changes, extensive wetness and poor drainage, lack of moisture or shifting soil are the culprits.
Consult a professional foundation repair specialist to assess and repair the situation. Landscaping services may also be necessary to alter water flow away from the house.
Stair-Step Foundation Cracks
Cracks in the mortar between several concrete foundation blocks are another sign of a settling foundation. Typically, finding cracks resembling the outline of a staircase isn’t as serious as finding horizontal cracking and is sometimes no concern at all. However, stair-step cracks can indicate real trouble if the cracks widen, leak water or extend to the block’s exterior.
Preventing Foundation Cracks
Though there’s little you can do to prevent cracks forming from age, improper construction or concrete curing, you can take steps to minimize some of the effects of changing soil.
Consider taking these steps before finishing your basement and hiding the concrete or block behind drywall.
- Repair non-structural cracks as they appear to keep them from getting worse.
- Keep gutters and downspouts clear of debris.
- Slope the landscape away from the foundation.
- Install exterior drains if necessary.
- Limit lawn watering and repair sprinkler system failures
- Avoid planting trees or shrubs near the house.
No comments:
Post a Comment