Why an "Out of Level" Floor Might Not Be a Big Deal — and Why You Should Consult a Geotechnical or Forensic Engineer

By Michael R. Simpson, PE, Geotechnical and Forensic Engineer

As a geotechnical and forensic engineer, I often hear from homeowners who’ve been told by a foundation repair company technician that their floor is “out of level” and needs expensive repairs. This can sound alarming, but a 2001 Arizona State University (ASU) study on residential slab-on-grade floors in the Phoenix area shows that uneven floors are common in new homes and don’t always indicate foundation trouble. Instead of trusting a salesperson’s pitch, I recommend hiring a geotechnical or forensic engineer to determine if your home’s foundation is truly at risk. Here’s what you need to know.

What the ASU Study Reveals

The ASU study measured the levelness of 89 newly poured concrete slab floors and 9 slabs after homes were built on them, using a water level manometer. The findings are clear: newly constructed slabs were, on average, 0.53 inches out of level, with some as much as 1.18 inches off. Even after homes were fully constructed with framing and roofing, the slabs showed no significant change in levelness. The average maximum slope was 1/334, with some slopes as steep as 1/101—close to or exceeding levels where cosmetic or structural damage might occur, yet these homes showed no immediate problems.

These results challenge the idea that a perfectly level floor is standard in residential construction. The study makes it clear that deviations of about half an inch are normal and not necessarily a red flag.

Why a Sales Technician’s Claim Might Not Hold Up

Foundation repair companies often use levelness measurements to convince homeowners that their foundation is failing, pushing for costly fixes. But the ASU study shows that most new homes start with floors that are already uneven—sometimes by more than an inch. So, when a technician says your floor is “out of level,” they might just be pointing out how your slab was built, not evidence of damage or movement.

The study highlights a key issue with relying on levelness alone to diagnose foundation problems: it assumes the floor was perfectly level when constructed, which is rarely true. Without knowing the slab’s original condition, a technician’s measurement lacks context and could exaggerate the issue to secure a sale. To truly understand whether your foundation has moved since construction, you need more than a quick level check.

Why I Recommend a Geotechnical or Forensic Engineer

As a geotechnical and forensic engineer, I strongly advise consulting a professional like me instead of relying on a foundation repair salesperson. Geotechnical engineers specialize in how soil interacts with structures, while forensic engineers investigate existing structure issues to determine their causes. Together, these experts can provide an unbiased, scientific evaluation of your foundation’s stability. They will:

• Analyze soil conditions: Determine if expansive, settling, or unstable soils under your home are causing movement.

• Inspect for real damage: Look for signs like significant cracks, sticking doors, or distorted window frames that might indicate foundation issues.

• Compare to typical standards: Use data like the ASU study’s 0.53-inch average deviation to assess whether your floor’s unevenness is normal or a sign of post-construction movement.

• Offer objective advice: Provide clear recommendations without the pressure to sell you a specific repair service.

Unlike sales technicians, who may have a financial motive to recommend repairs, geotechnical and forensic engineers focus on facts, helping you make informed decisions about your home.

Act with Confidence

If a foundation repair technician warns you about an uneven floor, don’t panic. The ASU study confirms that deviations of around half an inch are typical in new homes, and even larger variations may not indicate structural issues. As a geotechnical and forensic engineer, I urge you to hire a geotechnical or forensic engineer for a thorough, unbiased assessment. They’ll help you determine if your foundation is stable or if action is needed, saving you from unnecessary repairs and giving you peace of mind.

Want to Dig Deeper? Read the full ASU study for more details or contact a licensed geotechnical or forensic engineer in your area for a professional evaluation. Don’t let a sales pitch scare you—get the facts first!

By Michael R. Simpson, PE, Geotechnical and Forensic Engineer