Foundation Cracks - Signs, Causes, and Types

Although our houses are built to withstand the test of time, it's not uncommon for them to wear down after a while. 

Just like we show signs of old-age through wrinkles, our houses show it through cracks and imperfections. With the weight of the house bearing down on it, flaws of wayward construction, and the surrounding pressure, the foundation of your house takes it all. 

Not only do cracks in your foundation look bad, but they can also result in the gradual loss of structural integrity, which can mean costly repairs. The sooner you fix foundation cracks, the easier and cheaper repairs will be.

Are you looking for accurate cost information related to foundation cracks? Perfect, you're in the right place. In this guide, you'll learn:

• When to worry about foundation cracks
• The various types of foundation cracks
• What causes a foundation to crack
• The warning signs for a crack in your foundation
• How to prevent a foundation from cracking
• When to repair a crack in your foundation
• How to save money if you have cracks in your foundation

Here's everything you need to know about foundation cracks.

When Are Foundation Cracks Serious?

The seriousness of a crack depends on the size, location, and whether the house has other signs of structural damage. A huge number of homes have cracks in their foundation, and the older a house gets, the higher the likelihood of imperfections/cracks appearing.

We'll get into the details below, but generally speaking, horizontal and stair-step cracks are the most dangerous and are always a cause for worry.

Other types of cracks can result from typical foundation settling, but any crack that goes beyond 1/8" wide at any one time is a serious problem and should be addressed right away. What's more, cracks that are broader on the top than the bottom should be a cause for worry.

What Are The Types Of Foundation Cracks?

1. Vertical Cracks

This foundation crack is quite common and can often occur within a few months of new construction. It looks just like you'd expect it to. This can be a spider web of vertical features crumbling apart or just one slowly widening crack. 

The nature of a vertical crack will depend on how soil is shifting under your house. However, vertical cracks often occur when one half of your house moves horizontally away from the other or when a section of the home is pushed up away from the rest, thus creating a fissure. 

Vertical cracks likely won't result in serious structural problems in a home, but they definitely can allow water to seep into your basement. The best course of action is to have this type of crack sealed with epoxy by a professional. Professional epoxy injections typically start at $500, but if you're banking on your own repair skills, you can get a DIY kit for as low as $75.

2. Horizontal Cracks

These types of cracks appear on your foundation walls, and they move horizontally without spanning concrete walls vertically. Cracks of this form are an indicator of severe foundation damage, and leaving them without repair could lead to the eventual collapse of your house.

Horizontal cracks occur due to a different type of soil movement. Suppose that your foundation is buried in several different layers of soil. One layer shifting or expanding more than others can cause stress to shear or hit your foundation horizontally. The effect will gradually show on your foundation walls.

These cracks shouldn't be ignored as they can result in significant loss of your foundation's structural integrity, particularly if they traverse corners of your crawl space or foundation. The best way to remedy horizontal cracks is to have them inspected immediately by a structural engineer. The good news is that horizontal cracks aren't that costly to repair and can even be repaired with lifetime guarantees and transferable warranties if you end up selling your house later on. 

3. Diagonal Cracks

These cracks are very similar to vertical cracks, but they run at an angle less than 75 degrees and greater than 30 degrees (mostly 45 degrees). 

Diagonal cracks could be signs of bigger problems and should be inspected by a foundation specialist or a structural engineer, especially if they span corners of your crawlspace or foundation. The remedy might be just to seal them with epoxy crack injections. Repair costs for these cracks range from $75 for DIY kits to $500 and for expert crack repair.

4. Stair-Step Cracks

Much like horizontal cracks, stair-step cracks are severe and often indicate major foundation movement. They form a stair-step pattern as they span horizontally between concrete blocks, then vertically, then horizontally, and so forth. 

For older houses with leaky basements, stair-step cracks are often the culprit. While the issue can be rectified with help from professionals/contractors, wear and tear in an older home is simply a fact of life. That said, it's wise not to apply a polyurethane sealant to stair-step cracks as it is a total waste of money.

5. Basement Hairline Cracks

These are often small cracks and form on your concrete floor. Hairline cracks often pop up within one year of construction and are mostly caused by the drying and settling of the new foundation.

The good news is that if you are a DIY homeowner, you can repair these cracks cosmetically for just $60-$200. But if you'd rather have a professional inspect and repair them, you'd have to spend $400-$600.

Pro Tip: If you acquired a new house and discover basement hairline cracks, be sure to get in touch with your home builder. Your warranty may cover any hairline crack repair costs.

What Causes a Foundation to Crack?

1. Earthquakes

When an earthquake occurs, it causes the ground beneath to shake, which in turn shakes your house around. Thankfully, most parts of the US are not susceptible to earthquakes.

However, it's important to note that even the tiniest of quivers can lead to cracks, especially if your foundation isn't stable or well-supported.

2. Soil Composition

Your house is a heavy structure. Suppose the earth beneath the foundation is of different densities (soil in one area and stones in another, for example). In that case, the foundation can settle unevenly (what is called differential settlement) and eventually crack. 

If you've noticed the doors and windows sticking, floors creaking, or you notice water seepage in your basement, it's highly likely that you've had a differential settlement. 

3. Hydrostatic Pressure

This occurs when excess water builds up around the exterior of your foundation. Cracks due to hydrostatic pressure are often found in areas that experience heavy rain or prone to floods.

4. Plumbing Leaks

Plumbing leaks in your home can spell doom. If your house lacks poured concrete foundations or basement waterproofing, the excess water will add to the earth, causing it to expand and push against your home's foundation.

5. Drought

Soil shrinkage occurs when soil is deprived of moisture. In our case, shrinkage happens when the earth below your foundation loses moisture, say during a drought. This causes soil to gradually pull away, creating a gap for the foundation to move. If your home's foundation isn't well supported, it can shift around, and fissures will start to appear. This is often the case when your foundation is laid on clay soil.

What Are The Warning Signs For Cracks in Your Foundation?

1. Windows or Doors That Don't Fit

When windows or doors begin to fit loosely or too tight, it can be a sign of foundation problems. There might be an issue if you can't fit a window or door to its hinge snugly. These issues can affect vents, garage doors, and other wall fittings.

2. Crumbling, Cracked, or Compromised Foundations

Begin by checking the foundation itself. Walk the outside and inside walls of your property and check for signs of:

• Gaps
• Sagging walls or floors
• Cracks or fractures
• Moisture or pools of water
• Flaking or crumbling concrete

3. Uneven Floors

You should be worried if the floor gradient is more than one or two inches every 15 feet.

4. Window Frame/Door Frame Separating From Brick

A door or window frame that's pulling away from the mortar wall should be a clear indicator that your home's foundation is in trouble.

5. Gaps on the Foundation or in the Walls

Keep an eye out for gaps/fissures in places where the floor, walls, or ceiling should meet flush. 

6. Warped Ceilings or Drooping Floors

Although some settling is normal, excessive drooping of the ceiling, walls, or floors can signify foundation issues.

How to Prevent a Foundation From Cracking?

1. Drain Water Away from the House

Don't allow water to pool around your house. The soil (especially clay soil) can expand dramatically and push against your foundation walls. Redirect any stagnant waters to areas far from your home. Do this using in-ground drains. As for roof and rain runoff, downspouts can help move the water elsewhere.

2. Plant Shrubs and Trees Away from Your Home

When drought strikes, shrub and tree roots tend to compete with soil for moisture. This can cause your foundation to settle unevenly and develop fissures. It's always prudent to plant trees several feet away from your property.

3. Water at Least Twice a Week

Water your foundation every day in the morning and before night for 30 minutes. Set a timer on your sprinkler for this task. This is particularly helpful in the first year of new construction.

4. Implement Proper Landscaping

Water typically runs downhill, and because you're trying to carefully control the amount of water around your house, the last thing you want is for all the rainwater to pool right under your roof. 

To avoid this, make sure that you grade the landscape about 6 inches in 10 feet of soil away from your house.

When Should You Repair a Crack in Your Foundation?

• If you find basement hairline cracks, don't sweat it. As long the cracks are hairline in width (within 1/8"), there's nothing to worry about.
• If a narrow crack is new, monitor it for expansion. Keep a close eye on the crack at least monthly for a few months and contact a professional if the crack expands.
• If the crack is wider than 1/8”, it should be sealed immediately. 
• If a horizontal crack pops up where the foundation meets the basement floor, it's not necessarily a structural issue, but the crack could use a sealant.
• If water is seeping through a crack, seal the crack and redirect the water.
• If a wall crack is wider than 1/2”, have a professional take a look right away.
• If a huge crack accompanies a bulge in a concrete wall, it shows a deeply-etched structural problem. Consult a professional immediately.
• If a crack is horizontal, it presents more of a risk than a diagonal or vertical crack. Consult a foundation expert before things get out of hand.

How to Save Money If You Have Cracks on Your Foundation

One of the best ways to save money on crack repairs down the road is to waterproof your foundation as soon as you move in. Admittedly, it is much harder to waterproof pre-existing/old houses than it is to waterproof new houses. Even so, there are solutions available to you that'll cost less to install than to repair your concrete foundation once the damage persists.

Carbon fiber foundation repair is one of those solutions. This method is gaining popularity in the construction industry mainly because the carbon fiber strips are quite affordable—a single strap goes for as low as $420. 

Alternatively, be on the lookout for free estimates and inspections from contractors or structural engineers in your area. Often, contractors/engineers will be able to offer you a free quote after a structural inspection. By comparing these quotes, you can better understand how much your foundation repair is likely to cost. Then you can negotiate with your engineer or contractor of choice to get the best bang for your buck.

Foundation repair contractors typically run their own small firms and are freer to negotiate than their corporate counterparts (like structural engineers) might be. If everything else hits a brick wall, don't be afraid to inquire if your preferred contractor has a payment plan available.

Handling foundation repairs can be a daunting prospect, particularly for new homeowners. Don't let your budget concern keep you from seeking out the foundation repairs you need, though. One rule of thumb always holds true: the longer you wait to fix a problem with your foundation, the costlier the eventual fix will become.

Can a foundation be made out of brick? Read my How to Prevent Brick Foundation Problems column.