Are Trees Bad For Foundations: Which Trees Affect Houses, Fixes & Prevention

While trees are nice to have around the house for fresh filtered air, they can sometimes be a burden. Trees are strong living things that exert force on the soil they grow on. This may leave you to wonder, are trees bad for foundations?

Here’s what I noticed from inspecting properties with trees:

Most trees that grow near a building don’t cause any damage to the house’s foundation. However, certain trees such as poplars, ash trees, and oaks may cause devastating damage to the foundation in a building. Understanding the different factors that affect the damage of trees to buildings, such as the depth of the foundation and the type of soil, can help you determine the perfect action to control the problem. In general trees should be planted at least ten feet from your homes foundation. This allows the roots room to spread as the tree matures. 

No worries, because I have done the research for you. Here, we explore the different ways that trees affect the foundation. 

Do Trees Damage Foundations?

Trees planted beside properties have a high probability of damaging the house’s foundation.

Even though trees usually grow very slowly, they exert a lot of pressure on anything they grow on. They will therefore affect any foundation when they come in contact with it.

Let’s look at different things relating to foundational damage by trees: 

Types Of Tree Damages

There are at least two types of damages as far as trees and the foundation is concerned. The two types include:

  • Direct damage
  • Indirect damage

Direct damage involves the roots applying pressure on the foundation structure. If the exerted force is higher than the resistance to that force, there will be damage. 

You might notice this situation in areas where tree roots have cracked tarmacs or lifted paviors. However, this is preventable if you apply planting techniques and kits designed to enable trees to thrive well. 

Trees are more likely to affect freestanding walls than they are to cause direct damage to the foundation of your house. This is because the foundation is designed with a greater resisting force than that caused by the roots. When roots meet resistance, they might grow downwards rather than upwards. 

The indirect damage is also called subsidence and heave. Even though they can result from other factors such as re-wetting of drought-affected soils and underground excavations, they are what you’ll notice as main concerns when a tree grows near your house. 

For tree subsidence to happen, three factors must be in place: 

  • Shrinkable clay soil
  • A structure
  • Woody vegetation or trees

Subsidence typically happens when an extended dry spell is intensified by trees drawing more moisture from the soil. The volumetric change on the ground causes it to sink, thus resulting in structural damage to any nearby foundation. 

How Tree Roots Impact The Soil

Tree roots have great power, whether they are newly forming or small. Since the roots are constantly driven to locate more nutrients and water sources, they extend themselves searching for these nutrients. The results from such movements depend on the type of soil that the tree is growing in. 

Two main types of soil are greatly affected by a growing tree. The first soil is mainly clay soil which compacts more easily. It also becomes more densely packed when the tree roots push through it. 

The second type involves soil that has loose rocks and dirt. This soil tends to be displaced and shifted, allowing roots to move through easily. Understanding the type of soil your home sits on can inform you of the kind of damage that the foundation experiences. 

The prevailing weather conditions may also determine how trees affect the soil and, consequently, the foundation. For instance, during droughts, clay soils dry, and the roots shrink. When there are heavy rains, the roots will absorb more water and expand in the process. Both expansion and shrinkage can damage the integrity of the soil and, consequently, your foundation. 

Concrete Settling & Foundation Damage

The roots aren’t the direct source of foundation damage as much as most homeowners believe they are. The main cause of damage to your foundation is the changes in the soil condition around your home. 

This showcases itself in the form of concrete settling. In most cases, concrete settling is unsightly but can also become dangerous. 

When concrete settles, it usually shifts and cracks in the process. Depending on how strong the movement turns out, the structure of your home might be affected. If your concrete foundation cracks because of root activities, the foundation won’t be affected, especially for new homes. 

If concrete shifts by any chance due to settling, residential foundations will be substantially impacted. In extreme situations, more so for older homes, the whole building structure might be affected. 

Some of the damages that you might encounter include ceilings becoming uneven, support beams shifting, and walls cracking or sinking. Even though concrete settling isn’t always a hazard, it can lead to basic structural damage, more so in older houses. 

What Trees Cause Foundation Problems?

There is no denying that trees bring so many benefits into our lives. However, we never think or focus on the difficulties and consequences of having trees near a building. 

Even though trees offer shade to sit in by blocking sunlight and mitigating the strong winds during winter, those with shallow roots damage the foundation.

This might be something that you aren’t even aware of. So which trees can cause damage to your foundation?  

Oaks

Although oaks make up just a small percentage of the total population of trees in the United States, they account for at least ten percent of the damage on foundations. Whether the oak tree is evergreen or deciduous, it has a fast-growing and shallow root system. 

Such root systems will spread and take up many nutrients and water from the soil around them. The roots are likely to lead to cracks in pipes or foundations to access more water and nutrients. 

The most likely types of oaks to cause damage to your foundation include red oaks, chestnut oaks, live oaks, and water oaks. For this reason, you should avoid these types of oaks near your house. 

Poplars

The poplar trees also have a fast-growing and shallow root system. The roots of these trees normally break into pipe cracks, thus leading to sewer pipe damages. 

However, some popular type of trees happens to be more aggressive than others. One such type is the white poplar. These types of trees are even up to 100 feet and have dark foliage and wide crowns. 

There is also the cottonwood poplar that contains aggressive roots. It also has water-seeking roots that are dangerous, especially around foundations to older houses. 

Other poplars with fast-growing shallow roots include the eastern poplars, Lombardy poplars, the balm of Gilead poplars, and Carolina poplars. 

Ash

Ash trees are also reputable for causing foundation damages. The most common ash tree that causes foundation damage is the white ash tree.

Just like the white poplar, the white ash is also very tall with widely spread roots. There are also the Carolina ash trees which are native to North America. These trees grow to almost 30 feet tall and normally thrive in swampy areas. 

Then there are green ash trees which can have a root spread of up to 30 feet. They can therefore damage a foundation, especially if they are closer to your home. These trees have water-seeking roots that spread out to locate saturated and moist soils. 

Other Trees

Even though poplars, ash, and oak trees are the most common sources of foundation damages, other trees can also lead to foundation problems. These trees are deciduous, such as boxelder, silver maple, black locust, tulip tree, sycamore, and sweetgum. 

Some evergreen species result in foundational problems, including the Crimean pine, the Norway Spruce, the Brewer weeping spruce, and the Swiss stone pine. Even though these aren’t all the trees that’ll lead to damage to your foundation, they’re certainly trees that can cause you problems. 

If you plant such trees closer to your house, you should implement special care to keep the roots far enough from your home. This way, you’ll have less damage to your foundation. 

How Do Trees Affect House Foundations?

Apart from just affecting foundations directly, trees are also known to affect the foundations indirectly. Let’s look at how trees affect foundations and buildings:

Damage To Foundations & Buildings

Although trees are known for growing slowly, they exert a lot of pressure on the surfaces growing near or through. As these trees move through the soil in search of nutrients and water, they end up displacing soil around them. 

Clay soil will compact more tightly. However, dry and loose soil in the arid climates might shift and become ineffective for supporting a structural load. Even though the roots don’t have direct damage to your foundation, the displacement of the soil that they cause might affect the integrity of the soil where your home sits together with its supporting structure. 

If by any chance the soil moves, anything that is above it will also move, including the foundation. This is more common in older buildings where the deteriorated materials can settle down or rise over time. You might therefore notice some cracks on your home’s foundation. 

Plumbing Damage

Most houses that are designed for habitation are developed with drainage systems that dispose of sewage and water. Such systems attract tree roots, especially during the rainy season or in areas with a lot of water. 

Some species such as maples, aspens, and willows are invasive since their root system can develop to any place in search of water. Most drainage pipes are perforated to allow the movement of the wastewater from the house to the ground.

Roots can grow through the perforations and, in worse cases, even block the pipes to the point that they either split or become non-functional. 

Sometimes, even old clay pipes that have deteriorated over time are susceptible to invasion by the roots. The pressure from the invasion results in cracking witnessed on the foundation of your house. 

Landscape Damage

Even though trees are a good addition to your homestead, their roots can occupy the areas meant for other plants and ruin expensive and elaborate plantings. As the trees age, you might see roots on the soil’s surface, a process enabled by erosion and wind. 

If trees grow together, they are also forced to compete for the available nutrients and water. However, the gardening in the spaces between and around them becomes limited due to intertwined roots growing below the soil surface. If you put asphalt down too thinly on an area between or near trees, it might bulge, buckle, and eventually crack. 

Even though roots don’t penetrate through solid concrete, walkways and certain areas may buckle from the movement of the soil generated by the roots. 

Can Tree Roots Go Through Concrete?

Tree roots rarely go through the concrete foundation to cause damages. However, the roots might go through the existing cracks, enlarging them in the process. 

The tree roots normally absorb water leading to the contraction of the soil. As a result, the concrete around the plants will break. 

However, if you take good care of your foundation, you’ll never encounter any cases of damage to it. 

Signs of Roots Under The Foundation

You might be wondering what the signs that there are roots under your building’s foundation are? Here are some of the signs

1. Your House Slant in The Tree’s Direction

The loss of moisture can lead to your building slanting in the direction of the tree. The side near the building will settle since the tree will draw moisture out of the soil. The foundation will therefore detach in the process resulting in a collapse. 

2. The Foundation Damages Closer To A Tree

Most damage to the foundation results from the adjacent trees. Some trees can draw over one hundred and ninety gallons of water daily. The soil under your foundation will therefore be without moisture, thus collapsing. 

3. Damage On The Foundation Side Receiving Most Sunlight

There is no question that trees need light to grow. They will therefore be attracted to the side that gets the most light. The more trees in that area, the more roots that the tree will produce. This will translate into damage to the foundation. 

How To Fix and Prevent Tree Foundation Damages

You should consider the following if you want to either fix or prevent damage by tree roots on your foundation:

1. Avoid Touching The Tree

Leave the tree alone if there is a tree near your house and there are no damage signs. 

2. Implement Preventive Landscaping

Preventive landscaping is a cost-effective approach to preventing foundation damages from trees. Here, you can implement the following:

  • Cutting or trimming tree roots to limit them from growing in the direction of the foundation. 
  • Never plant trees or shrubs near your foundation.
  • Plant only trees that have a non-invasive root system in your home.
  • Avoid trees with roots that grow horizontally or those that need a lot of water. 

3. Install Root Barriers

Installing a root barrier is the only option you have if you can’t remove a tree. Root barriers help to control the growth of roots near the foundation. They are normally overlapping plastic sheets. Their primary role is to divert roots from your foundation. 

4. Installing Irrigation Drip Lines

If trees near your house happen to be sucking the nearby soil dry, then you should add water around the trunk’s base. Install it a few inches from the soil’s surface for your irrigation drip line to offer effective outcomes. Here, you should hire a professional to help you out. 

5. Get Rid of The Tree

If the above preventing approaches fail, then the only option left is to remove the whole tree. You should also involve a professional here since tree removal can be dangerous and cause severe damage to the foundation if done wrongly. You should ensure that everything, including the roots, is removed. 

Conclusion

As we have seen, most trees that grow near buildings don’t cause any damage to the foundation. However, Trees such as poplars, ash trees, and oaks can have devastating effects on your foundation. 

To determine the perfect action for controlling the problem, you must understand the different factors that affect the damage of trees to buildings, such as the depth of the foundation and the type of soil. However, you might have to involve a professional if you want to acquire effective outcomes. 

Sources:

Myth #3 Tree roots will damage my house

What Kind of Structural Damage Can Tree Roots Cause?

Which Trees Wreak Havoc on Your Foundation?

How Tree Roots Damage Your Foundation

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Hubert Miles

I've been conducting home inspections for 17 years. I'm a licensed Home Inspector, Certified Master Inspector (CMI), and FHA 203k Consultant. I started HomeInspectionInsider.com to help people better understand the home inspection process and answer questions about homeownership and home maintenance.

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