DIY – How To Fix a Crack In Your Homes Foundation Yourself

Over time the foundation on your home will slowly begin to show signs of aging, the same way that we do when we get older. From the weight of the home sitting on it to the changing weather each season, the foundation puts up with a lot.

When it comes to foundation cracks, the most common type that you’ll likely see is a vertical crack that is caused by shrinkage and from the home settling. They can occur due to concrete tension, and become most visible during the first few years of construction.

Most foundation cracks can be easily fixed, even by a do-it-yourselfer, for a fraction of the cost that you would pay a professional contractor. Understanding what type of crack you are dealing with is crucial to maintain the structure of the home.   

Are Cracks in Foundation Normal?

Foundation cracks, for the most part, are normal and shouldn’t be a cause for an alarm. Foundations crack naturally due to aging or deterioration of the concrete, or from home settling over time.

Other times the foundation could crack due to the contraction of concrete during its curing process. Typically within the first year that home was built, you might begin to see these types of cracks appearing.

Regardless of what type of cracks you notice, it is very important to keep an eye on them to make sure they are not getting bigger. When cracks start to get bigger, so will the problems you’ll have.

Is The Crack Dangerous or Normal?

It is not unusual for your foundation to begin to crack. Foundation cracks can come in many different shapes and sizes, and knowing which ones are more serious then others is very important. Most cracks are due to the home settling naturally and not a cause for you to be worried.

In newer homes, you might see what is called shrinkage cracks. Shrinkage cracks can occur within the first year that the home is built, and generally not a cause of concern. What happens is that when the concrete foundation gets poured, it contains thousands of liters of water, and over time that water will slowly evaporate, causing the concrete to dry and slowly crack. Most of the time you will see shrinkage cracks under basement windows and above door frames. It is not uncommon to also see shrinkage cracks in the middle of the wall as well.

A more serious type of foundation crack that can occur on newer homes, but is not uncommon to see on some older homes, is caused by the ground moving. This type of problem will require a full excavation of the surrounding foundation walls. So knowing which type of crack you are looking at is important.

Vertical Cracks in Foundation

Vertical cracks in your foundation are typically the most common type of crack that you will see. These types of cracks are normally the result of the home settling, wall movement, tipping walls, or shrinkage due to the concrete drying. They can usually be found in the middle sections of a wall, and run vertically up and down, or diagonally.

If your vertical crack is wider than 1/8 of an inch, it might be best if you had a professional come out and take a look to make sure it’s not something that you should be more concerned about.

You might find that measuring the crack with a ruler or a tape measure could prove a little difficult in trying to determine the exact width. An easy reference to use is: A credit card is 1/32 inches wide, a nickel is 1/16 inches wide, and two dimes together are 1/8 inches wide.

Horizontal Cracks in Foundation

Horizontal cracks are generally an indication of a much more serious problem. Horizontal cracks are caused by what is called hydrostatic pressure coming from the outside of the wall. This could happen due to heavy rains or flooding, and over time this pressure can cause the foundation wall to cave in, causing the horizontal cracks to appear as the wall slowly begins to give out.

If you notice horizontal cracks in the foundation, you should also be on the lookout for the following:

  • Horizontal cracks that veer-off into other directions.
  • The Floor above the foundation could begin to slop.
  • Vertical cracks that are wider at the top and narrows as it goes down the wall.
  • Is the crack wide enough to slip a whole dime in?
  • From the interior, does the wall look to be bulging in.

These are signs of a more serious problem going on that should have a professional contractor look at right away.

Stair-Step Cracks in Foundation

A stair-step crack is one of the more serious types of cracks that occur in concrete block and brick foundations. These cracks flow diagonal, going from the bottom to the top in a step-like pattern. Stair-step cracks are the cause of foundation movement.

Foundation can mean many different things when dealing with what causes the stair-step crack. Different things come into play, such as the location, size, and shape of the crack to determine the cause. You also need to look at things like the material from which the foundation is made from, the age of the building, construction methods, and other surrounding observations to fully understand what caused the crack in the first place.

Stair-step foundation cracks should be looked at by a professional contractor to make sure there isn’t a bigger problem to come.

How Much Does it Cost to Fix Foundation Cracks?

Cracks will normally start small, but without fixing them right away they can get bigger and become more expensive to repair. To determine how much it would cost to fix the crack depends on how serious the problem is and what caused it. Some cracks you will be able to repair yourself, while others will require the help of a professional.

There are complete kits available to help make it easy for you to repair the crack yourself that you can buy from your local hardware store or on Amazon for as low as $105 Click here to find repair kits.

These kits contain all of the same material that a professional would use if they were to come out to your home to repair the crack from the interior.

Keep in mind that if you have a finished basement, you will need to cut out the drywall to expose the foundation underneath to get to the crack. This could add an additional $75 to $150 for the material and paint if you were to do it yourself.

If You Hire a Professional

If you choose to hire a professional, you should have at least three different foundation repair contractors come out and give you a detailed quote right away. Make sure the contractor is bonded, insured, and licensed in your state. 

You can expect to pay anywhere from $300 to $14,000. Typically on average throughout the United States, the cost could range between $900 to $6,500.

Minor cracks are more affordable and could cost between $300 to $800 to repair. Minor cracks that occur due to the foundation sinking, or from access pressure on the foundation walls, are much easier to repair and will not cause structural damage if repaired quickly. Even a small crack that is 1/8 inches wide can cause much more damage to the structure if left unfixed.

If required, a soil report by a geotechnical engineer can cost between $500 to $2,000, depending on the problem, level of details needed in the analysis, and who you hire.

Poor drainage is another common problem, and one that is not cheap to fix. For this, all of the dirt surrounding the foundation will need excavating so that a proper waterproofing system can get installed. The cost of fixing this type of problem could range between $2,000 to $7,500.

Typically, foundation cracks occur due to the home settling and sinking unevenly. Homeowners can expect to pay anywhere between $8,000 to $14,000 to have their home leveled off. For this procedure, the earth next to the foundation needs excavating so that several hydraulic piers can be placed underneath the foundation to help raise and level the house.

Some costs can even be much higher than $14,000 depending on how severe the problem is, and how large of a problem you have. It’s not unheard of to see some homeowners spend upwards of $30,000.

Many homeowner insurance policies do not cover the costs of foundation repairs.

How Do You Fix a Crack in a Foundation Wall Yourself?

Fixing a foundation crack from the inside is not a complicated process, and by doing it yourself, you could end up saving a few hundred dollars, not having to call in a professional.

I used the Fast Set Concrete Foundation Crack Repair Kit from Amazon, which cost $135 at the time (click here for current price).  Alternatively, there are other great repair kits available that all do the same thing, but I chose the package that I did because of the price tag and the good reviews from other buyers.

As you can see from the steps below, it is an incredibly easy process to do yourself using one of these kits.

Fixing Foundation Crack From The Inside

Before attempting to repair the crack, make sure that it is currently not leaking water. The inside of the crack can be damp, but the exterior surface should be dry for the ports to stick.

Step #1: Lay a plastic bag or newspapers on the floor, under the crack. Next, use a wire bristled brush or masonry brush to clean away any paint, dirt, and other debris from the crack and surrounding area, then wipe the surface clean using a rag.

Step #2: Starting at the bottom of the crack, measure up 4 inches, and then make a mark on the crack. Now, from that mark you just made, measure up 6 to 12 inches and place another mark. Keep doing this until you reach the top of the crack. These marks represent where the entry points will be for the injection process. If the crack is tight, you should place the marks closer together.

Step #3:  Insert the poxy paste into the caulking gun. Next, unscrew the cap and remove the plugs from the neck. Now, on a piece of cardboard, squeeze out approximately 4 ounces of poxy paste, then mix the two parts until you have a uniform grey color that doesn’t have streaks.

Step #4: Apply a small bit of the mixed poxy to either side of the surface ports, and place the ports over the crack on the marks that you previously made. The poxy should stick the port to the wall and not fall off. Ensure that the poxy hasn’t covered the injection portholes. Once you’ve placed a surface port on each of the marks, allow 15 to 20 minutes for the poxy to set.

Step #5: After 15 to 20 minutes, mix an additional batch of the poxy paste, and stir it up to get that consistent grey color. Apply the mixed poxy over the crack at least 1/8 to 1/4 inch thick, and at least 4 inches wide on either side of the crack. Apply a little extra around and over the base, and part of the neck on the surface ports as you go. Allow 45 to 60 minutes for the paste to cure.

Step #6:  Once the paste has cured, fill the provided plastic bottle with water and start to squeeze water into the top port. You should notice some water coming out of the port below. Continue squeezing water in each port down the crack.

Step #7:  Unscrew the cap on the Hydra Stop 300 container and remove the plugs inside. Attach the long 24-inch neck to the Hydra Stop 300 container, securing it tightly with the attachment cap. Then, place the Hydra Stop 300 into the caulking gun.

Step #8: Starting at the bottom of the crack, tightly insert the nozzle into the surface port and slowly begin to inject the Hydra Stop 300 solution. It is important to take your time while injecting each crack, as it could take up to 5 minutes to fully inject the crack. The tighter the crack, the longer it could take.

Once you see the solution ejecting from the port above, you can stop and place a plug into the surface port to prevent the solution from leaking out. Repeat this step until you have injected all of the ports, and you’ve placed plugs in each one as you went. Allow at least 24 hours for the solution to cure.

Step #9: After 24 hours, you can remove the surface ports from the wall by banging down on them with a hammer, or you may also use a surface grinder or chisel for popping the ports off the wall.

What Causes Foundation Cracks?

Several different things contribute to causing foundations to crack. Most of the problems are related to either poor soil beneath the foundation or uneven moisture levels in the soil next to the foundation.

For example, the most common reasons for foundation cracks are generally caused by hydrostatic pressure or from foundation settlement. Hydrostatic pressure is caused by excess water build up in the soil next to the foundation, while foundation settlement cracks form when the soil underneath the foundation shrinks due to a lack of moisture.

Upheaval is another common cause for foundation cracks, which is the opposite effect of a settlement crack. Upheaval occurs whenever your foundation moves upwards due to the expansion of the coil underneath. This type of problem is one of the more serious kinds because it could cause your home to become unsafe to enter. 

Several reasons why foundations can crack:

  • Settlement
  • Deteriorating (aged) concrete
  • Shrinkage
  • Tree roots
  • Faulty construction
  • Poor drainage
  • Poorly mixed concrete
  • Unstable soil
  • Hydrostatic Pressure
  • Excessive moisture in the soil
  • Lack of maintenance

Cracks in the foundation will most often occur in weak points like corners, basement window frames, piped in areas, and walls. When you first begin to notice cracks in the foundation, it is important to keep track of them and make sure that they are not getting any bigger.

One thing you can do is take a pencil and mark on the foundation where the end of the crack is, and then over time, look to see if the crack has expanded past the mark to indicate that it is getting bigger. Don’t hesitate to call a contractor if you feel the crack is getting worse.


How To Identify and Repair Concrete Cracks – DIY For Beginners

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