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Have you discovered damage to your concrete foundation? If so, you might want to know what type of concrete is best for repairing it. Well, you came to the right place because we researched this question and have the answer for you.
All-purpose cement is used to repair common problems in concrete foundations. However, water damage on your foundation should be fixed with hydraulic cement, like portland cement.
Unfortunately, not all concrete foundation cracks can be fixed by cement. Learn about what causes damage to your concrete foundation and how to fix them in the succeeding sections. Read on!
How to repair a damaged foundation?
Small and hairline cracks in the foundation can be easily repaired with the right tools and concrete. Here are the steps to repair minor damage to your foundation.
Here are the things that you need to prepare before repairing your foundation.
We should always start by preparing safety equipment:
- Safety glasses
- Dust mask
Tools and materials
- Small wire brush
- Can of compressed air
- Old towel
- Vinyl concrete patching compound
- Concrete bonding adhesive
- Small paintbrush
- All-purpose cement or hydraulic cement
- Small bucket
- Shallow bowl
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Prepare the damaged area
- Use the hammer and chisel to widen the crack. This will not only make it easier to insert the patch later but will also get rid of any loose debris. Anything loose inside the crack is not ideal for holding the concrete patch.
- Once you’re done, remove dust and debris from inside the crack using the small wire brush. Getting rid of this will give the concrete patch a better grip inside the crack.
- Once you’re done removing the chunks that the brush can remove, use the can of compressed air to blow away the rest of the dust and debris—especially the fine residue. This is a great way of getting to the particles that the wire brush can no longer reach.
- Use the garden hose to rinse the inside of the crack.
- Use the old towel to remove all the excess water from the crack and any leftover dust.
Water Damage Cracking
If the damage to your foundation is caused by water, it is best to use hydraulic cement instead of all-purpose cement. Simply swap the hydraulic cement in the steps below if this is the case for your foundation.
The DRYLOK hydraulic cement is available on Amazon. Check it out through this link.
Small to Medium Crack Repairs
If the crack goes through the concrete foundation, fix the external damage first, then fix the other side of the damage from the inside.
- Place one part of cement and three parts of sand inside the bucket.
- Add water while mixing the solution. Keep adding water little by little until you end up with a thick mix. Let it sit while you mix another batch of concrete with a different concentration.
- Mix a small amount of cement and water in the shallow bowl.
- Keep adding water until you get a solution with a consistency that is similar to paint.
- Use a small paintbrush to spread a layer of the paint-like cement into the inner surface of the crack. Make sure to apply the mixture to all the inside surfaces of the crack.
- Use a putty knife to insert the thick concrete mix into the crack. Apply pressure as you add more concrete to force the mixture deep into the crack.
- Keep adding more concrete inside the crack until you have filled the crack with the thick concrete solution.
- Use any straight edge to level the surface of the concrete patch.
- Let the concrete patch sit to dry naturally for one to two hours.
- Once the patch has dried, apply a thin layer of cement on the surface of the patch using a trowel. Apply the surface cement using a circular motion. Level the surface cement with the surrounding surface of the foundation.
Hairline Crack Repairs in Foundation
Hairline cracks can be repaired with a vinyl patching compound. Larger cracks that are big enough to take cement can be patched with a cement mix.
- Use the small brush to apply a layer of concrete bonding adhesive on the surface of the hairline cracks. Wash the brush right away once you’re done.
- Use a small putty knife to apply the vinyl patching compound. Press it firmly to get the initial layer into the deepest layer of the hairline crack.
- Apply multiple times as needed until the hairline cracks are completely sealed.
Larger Than 1/2-inch Crack Repairs
If you see cracks that are larger than 1/2-inch or see chunks of the foundation falling off, then it is best to let a professional (preferably a structural engineer) check your foundation.
They should be able to determine the true extent of the damage, the best way to repair it, and how to prevent further damage.
What causes foundation damage in homes?
An important part of fixing foundation damage is knowing what caused it. Knowing this will allow you to address the cause of the problem. Addressing the cause will prevent any further damage so that the repairs that you will do will offer more permanent solutions.
The common causes of foundation damage are differential settlement, the presence of water around the foundation, and concrete expansion/contraction.
The ground around a foundation is slightly loose right after a house is built. It will then start to settle and become more compact as time goes by.
Vibration can increase the rate of ground settling. This vibration can come from nearby road traffic, seismic activity, the activity of a railway, or the activity from a nearby airport.
Once the soil settles, the underlying ground structure becomes uneven and will cause the foundation to move downward. Unfortunately, this downward movement is seldom even, and this uneven downward movement causes horizontal cracks in the foundation.
This is called differential settlement—the uneven foundation settlement of the ground under the foundation.
What are the signs of differential settlement?
It could take a few months to a few decades after the completion of the construction before there is sufficient differential settlement to cause visible damage to the foundation of your house.
However, it is still best to address any damage as soon as possible. Here are the signs that your house might be suffering from the differential settlement:
Cracks on the foundation
Common signs of differential settlement include horizontal cracks on the foundation wall and on the concrete slab supporting your house. When there is an uneven settling of the ground underneath your house, the concrete foundation will soon follow the drop and create horizontal cracks in the foundation.
Doors and windows are no longer square
When you notice that some doors or windows have become hard to open and close, that means that the frame is no longer square.
Once the foundation drops unevenly, the wooden frames will start to follow the uneven drop. This will cause door frames and window frames to go out of the square.
This is uncommon because the chimney will have to be part of the sinking side of the house. However, a tilting chimney, along with the two symptoms above, is a sure sign that your house is undergoing a differential settlement.
Bulging walls and breaks in drywall seams
This symptom is similar to windows and doors going out of the square.
Uneven walls will create bulging that is proportional to the amount of tilt. This can also result in the seams of the drywall breaking because the structure is no longer the same as when the drywall was first installed.
Presence of water
Accumulated water from rainstorms, melting snow, landscaping, broken water lines, and bedrock can collect around the house if there is no proper drainage.
This is called hydrostatic pressure. The constant application of this pressure on the house’s foundation can cause it to crack and bend. You can prevent this by making sure that water can easily drain away from your house.
Concrete expansion and contraction
Concrete—like any other material—expands at high temperatures and contracts at low temperatures. This is called thermal expansion.
Damage from thermal expansion can be prevented by installing an expansion joint. Basement floors usually have an expansion joint to prevent damage due to thermal expansion.
All-purpose cement is often used to repair foundation damage. Hydraulic cement should be used if the damage is caused by water.
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