Foundation Cracks: Normal Cracks and When to Worry

Brick foundation with a stair-step crack

Stair-step cracks in block foundations are usually a sign of foundation settlement that needs repair. Some foundation cracks are normal and may not require action.

Cracks in a home's foundation are a typical sign of an underlying structural problem. But not all foundation cracks are an issue to be concerned about. A cracked foundation warrants an inspection when combined with other symptoms. You may see wall cracks in block basements or poured concrete walls sagging inward at the top. You may also notice bouncy floors as your crawl space deteriorates beneath them. Even issues that may seem unrelated can indicate a problem with the foundation, such as sticking windows and doors, ceiling gaps, and a tilting chimney.

Ignoring these warning signs of a foundation problem can be catastrophic for your home’s safety, value, and appearance. While some foundation cracks are normal, others can lead to significant structural damage and allow foul odors, pests, and water to enter the home. Active cracks are the most serious and can result from drought or heavy rainfall. This foundation crack will slowly and continuously expand every day, month, and year.

This article will teach you everything you need to know about foundation cracks, including why they occur, the different types, and when to call your local foundation repair expert for help.

What Causes Foundation Cracks?

Foundation cracks are typically caused by one of three conditions.

  • Curing Concrete: When concrete cures, it creates minor cracks within the slab, often referred to as shrinkage cracks. At less than 1/16” wide, shrinkage cracks are typically harmless.
  • Foundation Settlement: The natural settlement of your foundation is caused by loose backfill, soil erosion, and other soil deterioration under or around the home. Settlement cracks are one of the most serious foundation cracks because they are consistently growing.
  • Soil Expansion: The expansion of soil occurs when the soil becomes wet or dry with changes in weather conditions. Wet soil can expand enough to place significant pressure on your home’s foundation. This can cause your foundation walls to bow inward and crack.

Common Types of Foundation Cracks

Some cracks in the foundation, including hairline cracks, are considered normal foundation cracks. These typically appear due to settling or concrete shrinkage. Other types of foundation cracks might indicate a serious structural problem. Take note of which scenario describes your foundation problem and find out what the next steps should be to solve it.

Horizontal Interial Wall Crack

Horizontal cracks are one of the most common wall cracks.

Horizontal Cracks

You may see horizontal cracks in your basement walls. These cracks commonly happen due to unbalanced soil and hydrostatic water pressure pushing against your foundation. Your foundation may lean inward, and water can leak from the crack. Horizontal cracks can occur in both concrete blocks and poured foundations.

Vertical Cracks

Vertical and diagonal interior wall cracks

These cracks grow in a straight line or at an angle.

Unlike horizontal cracks, vertical foundation cracks typically don’t present a significant threat. They usually occur in poured foundations and develop vertically up and down the foundation wall. Vertical cracks are caused by the natural settling of the foundation over time. They are usually harmless unless moisture seeps through the cracks and into the home.

Stair-Step Cracks

Exterior Stair Step Crack

Stair step cracks usually appear when there is a moisture problem.

Stair-step cracks are among the most concerning foundation cracks. They typically occur in block foundations and are particularly dangerous when they appear along mortar joints, which are vital to your foundation.

Stair-step cracks are caused by foundation settlement and moisture seeping in from the outside. Constant pressure from the surrounding soils can make the cracks grow faster, resulting in significant damage.

Hairline Cracks

Exterior Hairline Cracks

Hairline cracks can be resolved promptly.

Hairline cracks are typically found in new foundations. However, they usually do not appear until one year after the construction is complete, as the settlement of the new foundation causes them. Luckily, these cracks are usually minor and can be repaired quickly.

Diagonal Cracks

Diagonal crack in concrete foundation

Diagonal cracks at the corner of a window or door opening are usually caused by concrete shrinkage and aren't an emergency.

Initially, diagonal foundation cracks do not threaten the structural integrity of your home. However, as with any foundation crack, they can worsen over time.

Diagonal cracks are typically caused when concrete foundation walls cure. Most concrete diagonal cracks can be repaired using an affordable epoxy crack injection.

When Should You Worry about a Cracked Foundation?

Cracks in your foundation can be quite serious. As foundation cracks develop and grow, they put the structural integrity of your home at risk and become more expensive to repair. If you’ve noticed cracks in your foundation, it’s important to monitor them closely. It's important to keep watch for any foundation cracks you may have. Possibly having an active crack would mean your wall crack is lengthening, but luckily there are ways to recognize if yours is serious enough for immediate repair. Cracks that display the following characteristics can indicate a severe foundation problem:

  • Moisture or odors are seeping in through the foundation crack.
  • The foundation crack is more than ⅛ inch in width.
  • The foundation crack grows significantly over time.

Foundation cracks can be a natural occurrence of your concrete settling over time. Certain foundation cracks, such as vertical cracks, can appear troublesome but are typically insignificant. However, it is always a good idea to have your foundation crack inspected by an expert to identify the root cause of the problem and determine if foundation repair is necessary.

Foundation Crack Repair Solutions

There are many types of foundation crack repair methods. The technique used to repair your cracked foundation will likely depend on the type and severity of the crack, as well as any other underlying foundation problems. Some of the most common foundation repair solutions include:

  • Bowing Foundation Wall Repair: Foundation wall anchors and braces are the best way to combat a failing foundation wall. They permanently stabilize the foundation wall and prevent future damage.
  • Leaky Foundation Wall Repair: Foundation piers, wall anchors, and braces will fix leaking foundation walls.
  • Bowing and Cracked Foundation Wall Repair: Carbon fiber straps reinforce foundation walls and restore them to their original position.
  • Leaning Foundation Wall Repair: A leaning foundation wall can be stabilized and repaired using common foundation repair methods, including wall braces and anchors.
  • Settling Foundation Wall Repair: Steel piers or a polyurethane injection system will straighten settling foundation walls.

It's essential to repair foundation problems as quickly as possible to protect your home's safety, value, and structural integrity. Contact your local foundation repair expert for a free foundation repair estimate if you're concerned about foundation cracks or have noticed other signs of foundation settlement.

Common Questions About Foundation Wall Cracks

Which Foundation Cracks are the Most Dangerous?

Stair step cracks are typically the most dangerous foundation cracks. This type of crack most commonly occurs in concrete blocks and brick foundations.

Which Foundation Cracks are Normal?

Vertical foundation cracks are normally nothing to be concerned about. They are a common sight in many homes and are caused by excess rain putting pressure on the concrete foundation.

Can I Repair My Foundation Crack Myself?

Some foundation cracks can be repaired using a simple kit from a hardware store. Vertical cracks can be sealed using water-resistant epoxy and can be avoided by regularly cleaning your gutters and strategically angling downspouts away from the foundation. More complex foundation cracks, such as horizontal cracks, need an expert's opinion. If you are unsure about repairing a cracked foundation or other problem, always call your local foundation repair company for their expertise.

Why Should I Repair My Foundation Crack?

Foundation cracks will worsen over time, leading to more damage and expensive repairs in the future. Without repair, foundation cracks create a perfect entryway for moisture and odors. Moisture can lead to mold, mildew, pests, and poor air quality. It can also result in water damage and standing water inside your home, potentially ruining clothing, carpets, and other valued household items. Replacing these items can be very expensive - especially when coupled with the cost of repairing the cracked foundation.

Having foundation cracks inspected and repaired before they worsen will save you time and money. Plus, there’s nothing like the confidence and peace of mind you’ll gain from knowing that your home is protected!