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Foundation Cracks: How To Identify Issues & Prevent Future Cracks

Sam Smith Foundation Repair Consultant

Foundation damage under a house

If you’re in search of accurate foundation crack repair costs, you’ve come to the right place.

Here’s what you’ll learn by the end of this article:

  • When foundation cracks present major issues
  • The different kinds of foundation cracks
  • Why foundation cracks form
  • How to prevent ongoing foundation damage
  • How to save money when repairing your home’s foundation cracks

The foundation under your house offers support and structure to your home and resists the soil pressure continually. Foundation damage is typical in response to severe stress, but not all foundation cracks indicate structural problems.

Poured concrete foundations can crack for various reasons. Some types of cracking can just be sealed, while others should be taken very seriously because they can lead to foundation failure and house collapse.

All homeowners should know how to identify when foundation problems are more severe and fix them regardless of severity.

In this article, we’ll go over the kinds of cracks you may see in your foundation, when they represent deeper problems, and how to fix them adequately and permanently.

When Do Foundation Cracks Present A Problem?

There are some types of gaps in your concrete block walls or concrete slab that shouldn’t cause too much panic.

Hairline cracks or any gaps less than ⅛” wide in your basement floor or cement walls that don’t run horizontally are most often caused by normal concrete settling. These can be sealed to prevent water seepage but don’t usually indicate loss of structural integrity.

Cracks that run vertically or diagonally that get wider than ⅛” should be sealed as quickly as possible to stop water from coming in through them.

Horizontal cracks and stair-step cracks are far more serious and usually indicate structural damage. These cracks need to be inspected by a structural engineer and repaired by a professional.

What Are The Types Of Foundation Cracks?

Foundation cracks are common, so you should be familiar with each type so that you can identify which are present in your concrete walls or slab.

We’re going to discuss each of the different kinds of foundation cracks you’re likely to see and their causes.

Vertical Cracks

Cracks that run up and down in your foundation wall are referred to as shrinkage cracks because they are most often caused by the concrete’s settling.

These are the most common cracks you will see in your concrete block foundation. They should be sealed with a waterproofing caulk but don’t require reinforcement.

Horizontal Cracks

Cracks that run parallel to your basement floor are hazardous. They are most often caused by hydrostatic pressure in the soil around your home. Soil that becomes wet due to heavy rain or a high water table and excessive groundwater can put additional pressure on your foundation walls and create structural damage.

This type of foundation crack should immediately be inspected by an engineer and reinforced with underpinning or another professional and permanent solution.

Diagonal Cracks

Cracks that run diagonally are usually only problems because they can allow water into your crawlspace or basement.

They can also indicate differential settlement of your soil, so they should be inspected by an engineer to be safe. Your inspector will need to determine the severity of the damage. The solution could require standard waterproofing products or foundation reinforcement.

Stair-Step Cracks

Stair-step cracks travel up your foundation wall like stairs. This kind of damage is similar to diagonal cracking in that it can be caused by rapid soil settlement and indicate structural damage.

These gaps should be addressed by an engineer and a foundation repair specialist.

Hairline Cracks in the Basement Floor

Thin cracks that spread across your basement floor are common and are often caused by typical settling. They should be treated with an epoxy or thick polyurethane paint once they stop spreading to prevent water seepage.

Why Do Foundations Crack?

Cracked foundations often present concern for homeowners because they don’t understand the cause. Many people worry about any cracking without knowing the severity of the damage. We will discuss the causes of cracking based on the location and the type of crack below.

Vertical and diagonal cracks in your concrete walls usually form due to the natural settling of your foundation. These cracks don’t typically indicate structural damage, but diagonal cracks can signify differential soil movement and should be inspected.

Cracks that run parallel to your concrete slab are most often caused by undue pressure from the soil outside. Improper drainage of runoff or groundwater makes soil heavier and more likely to force your foundation wall inward.

A horizontal crack forms when the wall cannot bulge in any further without cracking and shifting at the fissure. Frost heave can cause similar foundation movement if the water in the ground freezes and expands into your wall.

Cracks that run diagonally up your wall but in the shape of stair steps are caused by uneven settling of the soil beneath your basement floor. One area of your ground sinks too much and stops supporting the foundation.

The result is sinking in that part of your foundation, which leads to stair-step cracks as your wall separates from itself.

What Are The Warning Signs For Foundation Cracks?

Large foundation cracks don’t form overnight. Leaking cracks and even dangerous horizontal cracks can usually be anticipated.

We’ll go over the warning signs you should pay attention to to predict and help prevent damages from becoming serious foundation issues.

There are some easily identified warning signs you can see on the outside of your home. Misshapen roofing is easy to spot and can indicate structural damage.

You may notice wavy or bowed roof shingles if your foundation is damaged. You can also look for chimney problems like leaning, crumbling, or separation from the side of your home.

There are more indicators on the inside of your house. You should first lookout for bulging of your crawlspace or basement walls. Hydrostatic pressure causes your concrete walls to flex before horizontal cracks form. Discovering this problem before the crack forms can save you money and frustration in the cure.

Windows or doors getting stuck or becoming challenging to open can be used to predict foundation instability. You may also notice cracks in your drywall near the corners of wall openings or uneven floors.

How Do You Prevent Foundation Cracks?

Water is your foundation’s mortal enemy and is the most likely cause of your foundation cracks.

The best way to prevent a foundation from cracking is to set up adequate drainage of runoff, groundwater, and excess rainwater.

You can do this by installing gutters and downspouts, grading the soil away from your foundation wall, and installing a French drain or other types of drainage system to reroute water away from your home.

You cannot stop vertical cracks or hairline cracks in your basement floor from happening because they occur due to normal settling. You can seal them and prevent water seepage instead of preventing them.

When Should You Repair A Foundation Crack?

You should always implement some kind of repair for any type of foundation crack. Hairline cracks, vertical cracks, and diagonal cracks that have been cleared of structural damage can be repaired less urgently with waterproofing. They should be immediately sealed if they reach a width of ⅛” or larger.

Horizontal and stair-step cracks must be addressed on a very urgent basis. You should call an engineer or concrete repair specialist as soon as bulging walls or horizontal or stair-step foundation cracks are discovered.

These cracks can quickly worsen and require extremely costly repairs. Reinforcement should be done immediately regardless of the size of the crack. Failure to do so can be catastrophic.

How To Save Money When Repairing Foundation Cracks?

Repairing minor foundation crack issues like hairline floor cracks or vertical cracks can be done cheaply as DIY projects. Your goal with this cracking is just to prevent water from getting in. Waterproofing methods can be done yourself and can save you quite a bit of money on labor costs.

We will warn that saving money upfront on more severe damage is not advisable. There are some temporary solutions for horizontal or stair-step cracks, but they never last and will require more extensive reinforcement in the future.

Which is why we strongly recommend getting one of our professionals to get the repair done right the first time. Doing so can save a ton of money on future repairs.

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Sam Smith Foundation Repair Consultant
SHORT BIO: Hey, I'm Sam Smith. I'm one of our service techs here at Regional Foundation Repair. I'm here to help you learn more about your home's foundation. I've been doing this for a while, so I have a few insider tips and tricks to share!

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