How do I know if my slab foundation is bad?

Author: Rosanna Schinner  |  Last update: Saturday, August 23, 2025

Look for cracked walls, sticking doors or windows, and gaps between walls and floors. Exterior brick or concrete cracks, plumbing issues, rotten wood, or carpenter ants are also red flags. Regular maintenance is key; keep an eye out for pests, termites, and humidity levels to spot foundation issues early.

When should I worry about slab foundation?

Visible Cracks: Large or expanding cracks in the slab, floors, walls, or ceiling may indicate significant structural issues. If you can fit a coin into the crack, it requires immediate attention. Uneven Floors: Floors that are no longer level or appear to be sinking can signal foundation problems.

What is the life expectancy of a slab foundation?

Slab foundations are durable and have a life expectancy of 80 to 100 years or more when properly built and maintained. That being said, there are many different types of slab foundations to suit homeowners' various financial and geographic needs.

How do you inspect a slab foundation?

– Inspect Floors and Walls: Look for cracks, gaps, and any noticeable shifts. Use a level to check for uneven floors and a straightedge to detect bowed walls. – Test Doors and Windows: Ensure they open and close smoothly without sticking. Misalignment or difficulty in operation can indicate foundation issues.

How can you tell if a concrete slab is bad?

You can tell if a slab is cracked in a few ways. One way is to look at the surface of the slab. If you see any cracks, then the slab is probably cracked. Another way to tell if a slab is cracked is to tap on the surface of the slab. If you hear a hollow sound, then the slab is probably cracked.

4 Key Signs That Your House Has Foundation Issues

How do you test a concrete slab?

Methods for Testing Compressive Strength of Concrete
  1. Rebound Hammer or Schmidt Hammer (ASTM C805) ...
  2. Penetration Resistance Test (ASTM C803) ...
  3. Ultrasonic Pulse Velocity (ASTM C597) ...
  4. Pullout Test (ASTM C900) ...
  5. Drilled Core (ASTM C42) ...
  6. Cast-in-place Cylinders (ASTM C873) ...
  7. Wireless Maturity Sensors (ASTM C1074)

How do you fix foundation problems on a slab?

Slabjacking is the Best Way to Repair an Interior Cracked Slab. Slabjacking is a method of concrete lifting, designed to restore a slab to its original position (or as close to it as possible). This is accomplished by drilling holes through the concrete slab and injecting a filler material underneath it.

How much does a concrete slab inspection cost?

Foundation inspection costs homeowners an average of $600 but typically ranges from $300–$1,000. See which factors will impact your total cost. Mark Howey is a licensed California building contractor with more than four decades of experience in the construction industry.

Does home insurance cover foundation repair?

Dwelling coverage, or Coverage A on your homeowners insurance policy, will likely cover foundation damage caused by covered perils. If the foundation damage is due to negligence, your insurance won't cover the repair cost.

When should I replace my concrete slab?

While concrete is much more resilient than other surfaces, it still has an “expiration” date. If your surface is facing 20-25 years of use, it is probably time to replace the concrete. Exterior concrete faces more elements than interior, so adjust your concrete age accordingly.

Is a crack in a slab foundation bad?

Foundation cracks may indicate a serious structural issue that requires professional evaluation and repair.

How do I know if my foundation needs repair?

What Are Signs of Foundation Issues?
  • Cracked Drywall. ...
  • Gaps Between Exterior Windows and Walls. ...
  • You Notice a “Sinking” Feeling. ...
  • Counters, Cabinets, or Other Static Structures Separating From the Wall. ...
  • Cracked or Leaning Chimney. ...
  • Cracks in the Walls or Floor. ...
  • Nails Popping Out of Drywall. ...
  • Warped Floors or Ceilings.

Why not buy a house on a slab?

One of the most significant potential disadvantages is if the slab cracks. This can substantially compromise the structural integrity of the house and be difficult and expensive to repair. Among the factors that can result in a slab cracking are tree roots, soil displacement, earthquakes, or frozen ground.

Should you waterproof a slab foundation?

' Many homeowners who have slab on grade foundations share this sentiment. However, every foundation can leak and every foundation needs waterproofing. This also includes slab on grade foundations.

How to inspect a slab foundation?

Slab foundation investigation involves a walk around the home and looking for cracks in the slab, or in brick veneer or fascia boards. Pier and beam foundations are examined by entering the crawlspace under your home and carefully examining it for any lingering wetness, or any signs of a musty smell.

How much does it cost to redo a concrete slab?

You can expect to pay an average price of $3 to $5 per square foot, if you are going for a simple or basic concrete resurfacing.

How do people pay for foundation repair?

Home Equity Loan or Line of Credit

Home equity loans and home equity lines of credit (HELOCs) are two popular ways to finance major home improvements, such as foundation repairs. But in order to be eligible for these financing options, you need to have enough equity in your home to serve as collateral for the loan.

Is it safe to live in a house with foundation problems?

We get asked a lot if it's still safe to live in your home when you have foundation problems. The short answer is usually yes, it is safe. Each house and situation is unique, but nine times out of ten, you can still live in your home. However, it honestly depends on the severity of the foundation problem.

How long does a foundation slab take to cure?

48 Days: 100%

Some companies say that you should wait a full 48-60 days to be safe. However, that may vary depending on many of the factors in this guide. You can start framing on a poured concrete slab about seven days after it's poured when it's close to 75% cured.

Does insurance pay for foundation repair?

Home insurance may cover some foundation repairs, but whether there's coverage depends on what causes the damage. Sometimes the event that damages your foundation isn't covered by your home insurance. When that happens, you're most likely going to have to pay for repairs out of your own pocket.

How does a structural engineer check foundation?

During the Inspection

Over the course of about 90 minutes, the structural engineer will: Examine the exterior for signs of settling or cracking. Inspect interior walls, floors, and ceilings. Check crawl spaces or basements for moisture issues.

Can a slab foundation be repaired?

Slab Foundation Repairs: Most Common Methods

After the home has been underpinned using either helical or push piers, polyurethane foam is often used to fill any remaining voids under the slab.

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