Trees and shrubs can increase the charm of a property, but they can also result in both shifting soils and foundation issues. When visiting a property for the first time – whether on a tour with clients or during a listing presentation – there are specific plants to note. In Texas, there are a variety of invasive trees and shrubs which can lead to costly future foundation repair and house leveling, when left unchecked.
The reason certain trees and shrubs cause foundation damage is due to their roots. As roots grow and move through the soil they can cause “subsidence”, which is the process of soil swelling as it becomes saturated and shrinking as it dries. Subsidence is a common occurrence with the heavy clay soils found in Texas. Tree and shrub roots extract water from the surrounding soil and lead to subsidence beneath a property’s foundation. Some species will even grow roots so large they may loosen and heave soil due to their changing girth. Highly durable roots may also invade cracks and enhance foundation problems caused by shifting soils.
When it comes to dealing with foundation repair and house leveling, some trees and shrubs may be more to blame than others. Knowing how to quickly identify these trees and shrubs can help your clients fully understand the costs associated with buying or selling a property.
Types of Invasive Trees
Fast-growing trees and those with extensive root systems pose the greatest risk to the strength and health of a foundation. In general, a tree’s height is roughly the same as the distance you can expect its root system to grow. This is why tall trees planted close to a property can be cause for concern.
Poplar trees are a popular choice for many homeowners because they provide excellent shade. Unfortunately, all 35 varieties have extremely invasive root systems that grow rapidly near the surface, making them a poor choice for planting near properties. The root system of a poplar tree can grow two to three times the height of the tree. Many homeowner’s associations ban the planting of poplar trees for this reason.
Oaks are some of the largest and sturdiest trees in the world. While they are traditionally slow-growing, they can wreak havoc on a home’s structure and plumbing system. Oak roots can grow up to 100 yards out from the base of the oak tree. These roots can suck up moisture and even invade cracks within a foundation, leading to the need for potential foundation repair and house leveling in the future.
Sycamores are one of the oldest species of trees on Earth, renowned for their longevity and sturdiness. Unfortunately, the roots are also quite hardy. Sycamores tend to have an aggressive root system, and some even develop multiple trunks.
Ash trees are quite popular for ornamental landscaping, but they are also notorious for causing foundation and sewer line damage, especially the white ash tree. Many ashes grow naturally in moist soils with strong water-seeking roots.
This species of tree grows fast and its roots are experts at seeking out water. Although you will typically only see willows growing near rivers and streams, they still occasionally appear in nurseries. Moist soil and water lines act like a magnet to the roots of these water-loving trees.
Magnolia trees are known for their fragrance, but not as many people are aware that they can cause foundation and plumbing issues with their large, rope-like roots. These trees typically grow along the surface as opposed to growing deep into the ground. For this reason, they can quickly brush up against a property’s foundation.
Types of Invasive Shrubs
Much like trees, shrubs with fast-growing, aggressive roots are typically the highest risk when it comes to foundation issues. Keep a look-out for the following shrubs during tours and listing presentations.
Landscapers and homeowners frequently use one of the 80 different types of boxwood shrubs as a foundation hedge. However, while its aesthetic value is surely appreciated, its danger to the foundation often goes unnoticed, until it’s too late. With a large, shallow root structure, Boxwood shrubs can lead to an eventual need for foundation repair and house leveling when planted too closely to the base.
Holly Bushes & Trees
Holly bushes are another popular shrub in the Lone Star state. But without proper nutrition and moisture, the holly tree root system will branch out in search of more water. The roots need at least a few feet of space from the house in order to prevent them from invading any cracks in your foundation or causing soil shifts.
While ivy is aesthetically unique and can add a lot to a property’s appearance, it can also be a red flag for potential foundation issues. Ivy roots take hold in cracks and crevices. Generally the roots aren’t strong enough to create these crevices. If a foundation already has cracks, however, English ivy can invade these areas and lead to damp interior walls and structural damage over time.
What to Do if You Notice Harmful Trees or Shrubs
One of the first things you can do is ask the property owner if they have installed any root barrier systems around their foundation. Root barriers can be installed 3 to 5 feet deep to redirect tree roots away from a house. If they have been installed, the home may be protected from foundation issues caused by the trees or shrubs.
The next thing you can do is look for any current signs of foundation damage. If you notice any signs along with the high-risk landscaping around the property, odds are the house will need foundation repair and house-leveling in the future.
The third and most important thing you can do is call our experts at Perma-Pier for a no-cost evaluation. We’ll confirm whether any nearby root systems have compromised a property’s foundation and provide a free estimate for foundation repairs. We’ll also provide a written diagnosis of any foundation issues quickly, so your seller’s disclosure notice or your buyer’s inspection is fully updated with relevant information. Complete the form to schedule an evaluation.