How Tree Roots Can Threaten Your Foundation

A beautiful tree can add undeniable value to any property, providing shade and enhancing curb appeal. However, the same root systems that keep these trees anchored to the ground and thriving can end up posing a dangerous threat to the structure beneath your home.

Many times, homeowners do not realize the damage that tree roots can cause until after foundation issues have come to light. This guide explains how tree roots can damage foundations, how to spot warning signs of root-related damage, and the steps you can take to protect your home.

How Tree Roots Affect Soil and Foundations

Roots threaten foundations in two main ways. They can grow directly into concrete and cause physical cracks, or they can change the soil conditions around your home. Tree roots often cause foundation damage when the roots pull water from the ground, drying out and shrinking the soil around and underneath your foundation. Here’s how different soil types and moisture conditions contribute to these problems.

• How Soil Type Influences Root Expansion

Your soil type plays a major role in determining whether tree roots will damage your foundation. Clay soil is thick and dense, which limits how easily roots can push through it. However, clay soil becomes a serious problem when tree roots start removing moisture from it. As the clay dries out, it shrinks away from your foundation and creates empty spaces underneath. These voids cause your foundation to settle unevenly, sinking and cracking.

• Why Moisture-Seeking Roots Move Toward Foundations

Tree roots don’t grow in a random pattern; instead, they search for sources of water in the soil. Tree roots that detect moisture differences and grow towards moisture. Water often pools in the soil around foundations if it was not properly compacted during construction. It may also collect there based on several other factors, including condensation that forms on concrete, small leaks in nearby plumbing, and gutters dumping rainwater too close to your home. All of this causes tree roots to grow in the direction of your home.

Common Foundation Problems Caused by Tree Roots

The following are the major issues tree roots create for your home’s foundation:

• Foundation Cracks and Structural Shifting

As tree roots grow beneath your property, they search for water and nutrients in the soil. Whenever they reach your foundation, they continue to expand, pushing against the structure. Block walls are particularly at risk because roots can wedge between individual blocks and push them out of place. Slab foundations are equally susceptible to damage when roots grow beneath the foundation and force portions of the concrete upward.

• Uneven or Settling Floors

Sloping floors inside your home often indicate that tree roots are affecting the ground below your foundation. Trees draw moisture from the soil daily, causing the soil to compact and lose volume. This creates gaps under your foundation where solid support used to exist, causing the foundation to sink and settle unevenly.

• Damage to Underground Drainage and Plumbing

Small cracks in older pipes release moisture that attracts nearby roots searching for hydration. These roots enter through the damaged areas and expand as they grow, which widens the cracks until the pipes eventually break.

Warning Signs That Your Trees Are Causing Foundation Issues

If you have trees planted around your house, these are the common signs that their roots could be damaging your foundation:

• Cracks Around Windows, Doors, or Exterior Walls

Look for diagonal cracks spreading from the corners of windows and doors. In your home, you might see cracks forming in the drywall or ceilings. Gaps may also appear between walls and trims or around doors and window frames. Walk around your home and look for cracks on the exterior of your foundation walls, and watch for any leaking cracks in your basement or crawl space.

• Sudden Changes in Floor Level or Gaps Between Walls and Floors

Your floors may start to feel uneven as you move across them. Small objects such as balls might roll on their own toward the wall. You may notice gaps appearing between your baseboards and the floors, or new flooring materials, such as vinyl plank and tile, becoming buckled and cracked.

• Persistent Soil Dryness Near the Home

One indication of issues caused by tree roots is that the soil around your foundation remains unusually dry and cracked even after rainfall. This dryness may appear alongside sticking doors and windows that don’t operate smoothly. You’ll also see gaps forming around doors and windows as settling occurs.

• Trees or Shrubs Leaning Toward Moisture Sources

Keep an eye on the direction in which your trees or shrubs are growing. Trees near your home may lean noticeably toward your house instead of growing upright. Plants may show much lusher or faster growth on the side facing your plumbing or outdoor faucets.

Trees Most Likely to Damage Foundations

These are the tree species that pose the most risk to the structure of your property:

• Fast-Growing, Deep-Rooted Tree Species

Some trees grow so rapidly that their root systems are invasive to the point of being destructive underground. Oaks develop massive underground networks that constantly tap into soil moisture, causing the ground to dry out and shrink considerably. Other tree species, such as willows, poplars, and silver maples, can also be equally concerning because their roots extend far beyond their branches, actively seeking water and entering through the smallest openings in the foundation walls.

• Invasive Root Systems to Avoid Near Homes

Willows may be the worst trees to plant anywhere near your house, with roots that grow extreme distances and frequently enter sewer and drainage pipes. Other undesirable species include silver maples, which have shallow roots that break through surfaces, poplars that destabilize soil structure, and American elms, whose roots relentlessly pursue moisture around building foundations.

• Safe Distance Guidelines for Planting Trees

Small trees like dogwoods should be planted at least 10 to 15 feet of space from your foundation. However, larger trees require more clearance, with medium trees needing 15 to 25 feet, and tall trees, such as oak, 30 to 50 feet to prevent root damage.

Prevention Tips to Protect Your Foundation

Here are some effective ways to prevent tree roots from damaging your foundation without sacrificing the value that trees add to your yard.

• Proper Tree Placement and Planting Distance

Trees should always be at least 10 feet away from your house. Trees with invasive root systems should be planted at least 25-30 feet away from the house. Focus on trees that have moderate roots, such as English holly or olive trees, and avoid problematic trees like willows and silver maples.

• Root Barriers and Moisture Control Systems

Installing root barriers lets you control where your tree roots travel underground. These protective sheets go into the soil before planting and create a wall that forces roots to grow downward and not sideways.

• Monitoring Soil Moisture Near Your Home

You must keep the ground around your foundation evenly moist to stop the damaging cycle of soil expansion and contraction. Trees planted within 20 to 30 feet of your house need consistent watering using drip systems that add moisture slowly. When the soil stays hydrated at a stable level, it protects your foundation from movement and cracking.

• Regular Inspections by Foundation Professionals

Bringing in a foundation repair expert every 3 to 5 years can help you catch small problems. Homes on clay soil or near large trees should have their foundations checked annually. Always schedule an inspection after unusual weather like long dry spells or heavy rains, since these conditions can accelerate any issues.

How to Fix Foundation Damage Caused by Roots

Once tree roots have damaged your foundation, you’ll need to take specific steps to repair the damage and stabilize your home.

• When Root Pruning Is (and Isn’t) Safe

Removing the entire tree isn’t always necessary when roots threaten your foundation. A certified arborist can assess whether selectively cutting problematic roots will solve the issue without killing the tree. The success of root pruning depends on factors like how close the cuts must be to the trunk, the diameter of roots being removed, and the tree’s current health. Young, vigorous trees in well-draining soil generally handle root removal better, while older trees, those already in poor condition, or trees leaning to one side, are poor candidates because pruning could cause them to topple or die.

• Structural Repair Options

After addressing the tree roots, you need to fix the actual foundation damage that has occurred. Steel push piers or helical piers can be driven deep into stable soil beneath the affected area, in order to lift and support your foundation from below. For sunken concrete slabs, contractors use polyjacking with expanding polyurethane foam or traditional mudjacking with cement slurry to fill voids and raise the surface back to its original position.

• Restoring Soil Stability After Root Removal

The hollows left by removed roots need to be properly filled to keep your foundation from settling further. You should fill these spaces with compacted soil and reshape your yard so water drains away from the house. Placing root barriers underground during repairs will prevent other nearby trees from sending roots back into the same area. Foundation repair professionals can also stabilize your soil to prevent further movement and settling.

Protect Your Foundation With Professional Help

The trees in your yard might be causing damage without you even realizing it. If you’re noticing signs of damage in your foundation, a professional inspection is the best way to protect your home. Call CNT Foundations today to schedule a free inspection and protect your property.