Home > Foundation > Why Do Foundations Shift? And How To Prevent It

Why Do Foundations Shift? And How To Prevent It

Updated Nov 4, 2022

Updated Nov 4, 2022

Home > Foundation > Why Do Foundations Shift? And How To Prevent It

If you’re noticing wall cracks, uneven floorboards, or stuck windows, your house might be suffering from a shifting foundation. Like termites or exposed roofs, foundation problems can lead to structural weakness and a costly price tag for repairs. A shifting foundation can also result in broken utility pipes, structural warping, and damage to multiple portions of the home if left unattended. To help you avoid this creeping catastrophe, we’ll cover everything you need to know about foundation shifting, why it occurs, and how you can best prevent it.

What Are Foundation Shifts?

A foundation shift, also known as foundation settlement, is when a house’s foundation moves, sinking deeper into the ground. All homes will experience some degree of foundation settlement. Most settlements are harmless and occur during the first week of construction. However, some can last longer, up to five years, or even throughout the whole lifetime of the home. When this shifting occurs, it’s measured by the length of the shift and the shift type.

The lifetime of foundation shifts is categorized as follows:

  1. Immediate settlement: This is the most common type of settlement, and it occurs during the first week of construction after the foundation is laid. This settlement normally ends before construction is complete and is typically remediated by a structural engineer.
  2. Primary settlement: This settlement occurs over one to five years and is normally the result of water particles being pushed out of the underlying soil, causing the soil to compact and the foundation to sink.
  3. Secondary settlement: This settlement is a result of constant stressors affecting the soil. Secondary settlement can last for the lifetime of a home and will only end when these stressors have been removed.

There are two kinds of foundation shifts, uniform settlement and differential settlement.

Uniform Settlement

As the name suggests, this type of settlement occurs when all parts of a home sink at the same rate and stop at the same depth. Since the shifting is mostly uniform, a home will stay roughly level throughout the settlement. Of the two types of foundation shifts, this one is the least structurally damaging, only causing harm to utility and plumbing lines. You may also see small hairline cracks along the foundation and above doorframes.

Differential Settlement

This type of settlement is the most damaging. Differential settlement occurs when sections of a home shift at different rates, resulting in the home becoming uneven. The damage from this type of settlement can include the following:

  • Cracks in foundation, walls, and doorframes
  • Warping of the home’s frame
  • Sloping floors
  • Bowing of decks and porches
  • Warped windows and doors
  • Breaking and cracking windows
  • Tilting or detached chimneys
  • Weakening of structural integrity

What Causes Foundation Settling?

Sam Wasson / House Method Team

Foundation shifts can occur due to several factors, the most impactful of which are a lack of elevation, the type of foundation, and soil conditions. Furthermore, outside factors such as weather, building weight, and drainage can all affect foundation settlement. Here is a quick breakdown of the major causes of foundation shifts:

  • Inconsistent or overly moist soil: Soil expands and increases its hydrostatic pressure as it’s filled with moisture. As a result, the soil will push against a foundation, leading to shifts and cracks. If soil moisture is not accounted for early on, it can shift as the concrete foundation’s weight compresses the soil, pushing out the water particles. Inconsistent soil moisture may also result in differential shifting.
  • Soil compaction: If a home is not built on compact soil, the weight of the foundation will compact it, resulting in a shift.
  • Soil type: Certain soil types (like clay or peat-ridden soil) will expand when exposed to moisture. If a large amount of this soil surrounds the foundation, you’ll see shifting occur when moisture is introduced to your lawn. These shifts typically happen as the seasons change. During the dead of summer, the soil will dehydrate and compact, then expand again as it rains.
  • Poor drainage: Poor lawn drainage can cause many problems, including foundation shifting. If a lawn isn’t draining properly, water will pool in and around the foundation, causing expansion and artificially softening the ground.
  • Earth shifting: Sometimes, the soil beneath a house naturally shifts and moves over time due to gravity. This type of shifting happens to homes built on hillsides and results in differential settlement.
  • Major leaks: If a home experiences frequent plumbing leaks or pooling water in the crawl space, it results in foundation movement and shifting.
  • Plants growing too close to the home: Tree roots, or the roots from bushes and shrubs, can press into foundations, increasing soil pressure. These roots can get into foundation cracks, increasing existing damage.

What Are the Major Signs Your Home’s Foundation Is Shifting?

Canva

When shopping for a new home, old home, or constructing your own, keep an eye out for the following common signs of foundation damage:

  • Crack in floors, foundation, and walls: While hairline cracks are not always a problem, any wall crack larger than a quarter of an inch should be cause for concern. The most significant damage to look out for is horizontal cracks in foundation walls — these can be major signs of foundation issues like freeze-thaw damage.
  • Door and windows sticking: If a home has suffered from a serious foundational shift, it may no longer be level. As a result, it’s much more difficult to open and close doors and windows.
  • Uneven floors: As a foundation shifts, certain parts of the floor may dip downward or bow. This bowing is more easily seen on porches.
  • Bowed walls and separated cabinets: Walls will move up and down as a foundation shifts. This can lead to warping, which can cause disconnects between countertops and a backsplash. You’ll also begin to see cabinets pull away from walls. In the most extreme cases, door and window frames can appear crooked.
  • Diagonal cracks in door and window frames: One of the most visible signs of a shifting home is the long cracks in the drywall at the corner of a door and window frames that reach toward the ceiling.
  • Separated molding and baseboards: As walls begin to bend and warp, molding and baseboard separate from the walls – this can lead to an audible “pop” as the nails give.
  • Chimney and porch separating from the home: Another major sign of foundation shifting is structures like the chimney and porch separating from the home.

How Do You Prevent Foundation Shifts?

Canva

The best way to prevent shifting foundations is through proper preparation by hiring reliable structural engineers and soil specialists when constructing your home. Ideally, by working with qualified professionals, you’ll be able to build your home on soil with ideal moisture and proper elevation, preventing shifting in the first place. However, if you’re purchasing a home that is prone to shifting or is beginning to shift, there are some steps you can take to minimize the damage:

  • Ensure the gutters are functioning properly and draining water away from the foundation.
  • Control soil moisture levels by installing yard drains.
  • Keep rooting plants, like shrubs, bushes, and trees, away from your home.
  • Repair leaks in plumbing systems and utility pipes.
  • Properly waterproof your basement and crawl space.

Closing Thoughts

If you’re experiencing foundation issues, your best bet is to contact a foundation repair expert or a soil remediation company. These foundation repair specialists will be able to assess the damage your home and foundation have already suffered and provide the best options for your situation. Thankfully, foundation damage, while a serious problem, is repairable in most cases and can prevent more expensive damage if caught early enough.

Other Foundation Resources