Do Most Older Homes Have Foundation Problems?

If you’re looking at an older home-say, one built before 1970-you’ve probably heard the warning: foundation problems are common. But is that really true? Or is it just a scare tactic used by contractors to sell repairs? The truth is somewhere in between. Not every old house has a bad foundation, but many do. And knowing the signs early can save you thousands.

Why Older Homes Are More Likely to Have Foundation Issues

Houses built 50 to 100 years ago weren’t designed with today’s engineering standards. Back then, builders used materials and methods that worked fine at the time-but they don’t hold up as well today. Concrete mixes were weaker. Footings were shallow. Drainage wasn’t a priority. Many homes were built directly on soil without proper compaction or gravel layers underneath.

In places like Wellington, where the ground is prone to shifting due to clay soils and frequent rain, these older foundations are especially vulnerable. A house built in 1920 might have had a stone or brick foundation that’s now cracked, settled, or bowing. That’s not because the house is old-it’s because the foundation wasn’t built to last under modern conditions.

Common Signs of Foundation Problems in Older Homes

You don’t need a degree in structural engineering to spot trouble. Here are the most common red flags:

• Cracks wider than 1/4 inch in brick, concrete, or plaster walls-especially if they’re diagonal or stair-stepped
• Doors and windows that stick or won’t close properly, even after repainting or adjusting hinges
• Uneven floors, especially in the center of the house or near exterior walls
• Gaps between walls and ceilings, or between baseboards and floors
• Water pooling near the foundation after rain, or dampness in the basement or crawl space
• Chimneys pulling away from the house or leaning

These aren’t just cosmetic issues. They’re signals that the structure is moving. And movement means stress. Over time, that stress can lead to serious damage.

Soil and Weather: The Silent Enemies

One of the biggest reasons older homes develop foundation problems isn’t poor construction-it’s the ground beneath them. In New Zealand, many older homes sit on expansive clay soils. These soils swell when wet and shrink when dry. That constant expansion and contraction puts pressure on foundations.

If a home was built in the 1950s and never had proper drainage installed, rainwater flows straight toward the foundation. Over decades, that water softens the soil, washes it away, or causes it to swell unevenly. The result? One side of the house sinks slightly, and the whole structure tilts.

Tree roots are another hidden culprit. Large trees planted close to the house-common in older gardens-can suck up moisture from the soil, causing it to dry out and crack. That’s why you often see foundation cracks radiating from the base of a mature oak or maple.

Not All Older Homes Are Problematic

Let’s be clear: not every 80-year-old house has a failing foundation. Many were built with solid craftsmanship and have held up remarkably well. Some homes in Wellington’s historic suburbs-like Thorndon or Newtown-still have original brick foundations that show only minor hairline cracks after 100 years.

What makes the difference? Maintenance. Homes that had regular gutter cleaning, proper grading, and timely repairs rarely develop major foundation issues. A homeowner who noticed a small crack in 1995 and had it sealed with epoxy? That house is likely fine today.

The real risk comes from neglect. If a house sat empty for years, or if the owner ignored a slow-sinking floor, or if downspouts were disconnected for a decade-then yes, foundation damage is almost guaranteed.

How to Know If You Need a Professional Inspection

If you’re buying an older home, don’t skip the foundation inspection. It’s not optional. A qualified structural engineer or licensed foundation specialist can tell you what’s normal and what’s dangerous.

Here’s what a good inspection includes:

• Measuring floor levels with a laser level to detect uneven settlement
• Checking wall alignment and plumb with a digital inclinometer
• Inspecting the condition of footings and underpinning (if present)
• Looking for signs of past repairs-like steel beams or carbon fiber straps
• Testing soil moisture levels near the foundation

Avoid contractors who offer free inspections but then push expensive repairs. A true expert will give you a report that says: “Minor settlement, no immediate risk,” or “Significant movement detected-recommend underpinning within 12 months.”

What Repairs Actually Work (and What Doesn’t)

There’s a lot of snake oil in the foundation repair industry. Here’s what actually fixes problems-and what’s just a band-aid:

• Effective: Steel piers driven deep into stable soil to lift and stabilize the foundation
• Effective: Concrete underpinning to extend the foundation deeper into solid ground
• Effective: Installing or repairing French drains to redirect water away from the house
• Not Effective: Epoxy injections for wide structural cracks-they seal the crack but don’t stop movement
• Not Effective: “Foundation leveling” services that just pump mud under the slab (this often fails within a few years)
• Not Effective: Painting over cracks or filling them with caulk

If a contractor tells you they can “fix” your foundation in a day with a cheap solution, walk away. Real foundation repair takes time, precision, and often months to complete. It’s not a weekend project.

Costs and What to Expect

Repair costs vary wildly. A small crack repaired with epoxy might cost $500. A full underpinning job on a 1920s bungalow could run $25,000 to $50,000. The average for moderate foundation issues in New Zealand is around $15,000.

Insurance rarely covers foundation damage unless it’s caused by a sudden event like an earthquake. Most policies exclude gradual settlement or soil movement. That means homeowners pay out of pocket.

If you’re buying an older home, factor foundation repair into your budget. Even if the seller says “it’s fine,” get a second opinion. A $500 inspection can save you $20,000 later.

Prevention Is Cheaper Than Repair

The best way to avoid foundation problems is to prevent them before they start. Here’s what you can do:

• Keep gutters clean and downspouts extended at least 2 meters from the house
• Ensure the ground slopes away from the foundation (at least 1 inch per foot for the first 6 feet)
• Water the soil around the foundation during dry spells-especially in summer-to prevent soil shrinkage
• Remove large trees within 3 meters of the house if they’re causing dryness
• Check for leaks in plumbing or irrigation systems near the foundation

These steps cost next to nothing. But they can extend the life of your foundation by decades.

Final Thought: Age Isn’t the Problem-Neglect Is

An older home doesn’t automatically mean a bad foundation. Many of the most beautiful houses in Wellington are over a century old-and their foundations are solid because they were cared for. The real issue isn’t age. It’s whether the homeowner paid attention.

If you’re considering buying an older home, don’t let fear stop you. But do your homework. Get the inspection. Understand the risks. And don’t ignore the little signs. Foundation problems don’t appear overnight. They grow slowly. And if you catch them early, you can fix them before they ruin your investment.