Can tree roots damage a foundation? Yes, they can. While trees look beautiful around a home, the root systems of some trees can damage your foundation if the trees are planted too close to your home. Their root systems “drink” water from the soil, drying it out and creating voids under the foundation. If the home sinks into these voids, it will lead to expensive foundation repairs.
This article will cover the basics of how soil and tree roots interact, how tree roots can damage a foundation, signs tree roots might be damaging your home’s foundation, and more.
Soil and Tree Roots
Tree roots extend through the soil to seek out nutrients and water. How this affects the soil depends on the type of soil experiencing the root movement. For example, dense soil with a lot of clay will compact as the roots push through it. During dry weather, clay-rich soil will dry up and shrink. As this happens, any tree roots in the soil will also shrink because there’s no water for them to soak up. When it starts raining again, the clay-rich soil absorbs moisture and expands again. The tree roots also expand because they’re now able to soak up moisture once more.
This shrinking-swelling cycle – usually seasonal – creates movement under the foundation. Eventually, this movement could lead to something called “differential settlement.” This is when the home settles unevenly into the soil. Differential settlement puts a lot of stress on a foundation, leading to structural damage and costly repairs.
See the below graphic for a visual depiction of differential settlement.
Other types of soil are also affected by tree roots pushing through it as they grow. For example, if the soil is loose, the roots will move the soil around as they push through it. This can also lead to the formation of voids and differential settlement.
Can Tree Roots Damage a Foundation?
So, can tree roots damage a foundation? Yes. However, the damage isn’t directly caused by the roots. It’s caused by the roots moving the soil around the foundation leading to differential settlement. In other words, the tree roots are destabilizing the soil under the foundation, and this leads to the destabilization of the foundation itself.
In some cases, though, tree roots can directly cause damage to a home’s foundation. An example is when tree roots – looking for water and nutrients – find and enter existing foundation cracks and make them bigger.
Tree roots can damage sidewalks, driveways, etc., in the same way they damage foundations, either indirectly by causing movement in the soil under the slab or directly by pushing up against the slab. We’ve probably all seen examples of this on city streets.
Signs Tree Roots May Be Damaging Your Foundation
Differential settlement is a sign tree roots might be causing damage to your home’s foundation. As we pointed out above, tree roots usually don’t directly damage foundations. Instead, they cause damage by creating movement in the soil under the foundation, which leads to differential settlement.
Signs of differential settlement include:
- Windows and doors that don’t open and close properly.
- Horizontal wall cracks
- Diagonal wall cracks from the corners of doors and windows
- Floor cracks, especially floor cracks going all the way across the floor. A crack limited to one or two tiles was probably caused when something fell on the floor.
- Uneven floors
- Stairstep cracks in brick or masonry
- Torn wallpaper. (The wall behind the wallpaper might be cracked.)
- Ceilings and floors that are separating from the walls
- Moldings that are separating from the wall or ceiling
- Chimneys or porches that are pulling away from the house
What to Do if a Tree Has Damaged Your Home’s Foundation
If a tree has damaged your home’s foundation, speak with a tree specialist to see what they recommend you do about the tree itself. Possible solutions include trimming the roots, installing a root barrier, or removing the tree. Of course, you’ll also need to contact a foundation repair contractor regarding repair solutions that will fix the damage.
Which Trees Are More Likely to Damage a Foundation?
Although we recommend keeping all trees at least 20 feet from your home’s foundation, the following trees are more likely to damage foundations:
- Oak
- Ash
- Poplar
- Maple (Norway and Silver)
- Black locust
- Boxelder
- Spruce (Brewer’s weeping and Norway)
- Walnut
- Sycamore
- Cottonwood
Note: At Epp Foundation Repair, we’re not tree specialists. We repair the damage to your foundation caused by trees. We recommend contacting a professional landscaper for in-depth information about these trees and how their root systems interact with the soil and foundations.
How to Prevent Tree Roots From Damaging a Foundation
The best way to prevent tree roots from damaging a foundation is to keep large trees at least 20 feet away from the foundation. You should keep other types of vegetation such as shrubs and flowers at least 10 feet away from the foundation. For more information, see The Importance Of Proper Foundation Drainage Around Your Home.
