Trees are a desirable component to home landscaping, but they can pose a threat to homes and buildings in many ways.
Roots and Foundations
Contrary to popular belief, most tree roots are not capable of piercing or damaging intact foundation walls. They can however damage foundations in several different ways:
- Tree roots can penetrate existing cracks, which can cause further damage.
- Large root systems can extend beneath the foundation causing foundation and basement slab uplift.
- Root systems can also remove water from the soil beneath the foundation and concrete slabs which leads to settlement issues.
Other issues:
- Trees that are too close to homes may be a fire hazard. Soffit vents can provide access to attic areas.
- Leaves, broken branches and other debris can cause obstructions in gutters and downspouts. This can also lead to ice damming conditions during winter months.
- Old, damaged, or weak trees can be a hazard from falling branches.
- Tree roots can damage underground piping. Leaking sewer lines can cause tree roots to grow toward and into sewer lines causing obstruction and damage.
Structural Problems in Trees
- Dead and broken branches.
- Species specific defects, some species of maple and ash trees have weak branch unions, some fast growing species are weak-wooded and can be prone to damage at a young age. These are commonly found in some maple and aspen trees.
- Cankers, localized areas of sunken or missing bark. Cankers are caused by injury or disease. The presence of a canker can cause an increase chance of failure at the canker. The presence of a canker that encompasses half of the trees trunk can be especially hazardous even if the wood appears healthy.
- Hollow trunks and cracks.
- Advanced decay, soft areas and areas of missing wood can be especially hazardous. Fungal activity such as mushrooms growing on root stems and branches can indicate advanced decay. Trees decay from the inside out, with new growth on the outer surface, it is sometimes difficult to determine if a tree has a hollow trunk. Trees with hollow trunks may be fine if the ratio to new wood growth is adequate.
- Trees that lean more than 15 degrees. Generally, trees that bend more than 15 degrees should be removed if they pose a danger. Trees that grow this way originally are not as much of a danger as a tree that was straight but subsequently leaned due to wind or root damage. Large trees that lean due to wind damage seldom recover.
Suggestions
When planting trees it is advisable to keep them far away from the home. It is impossible to predict how far the roots will spread. Prevent root damage. In addition to providing nutrition for the tree, roots anchor the tree to the ground. The root structure is said to be as large as the tree canopy in many species. Trees with damaged roots are more likely to lean than trees with healthy root systems. Dead trees within range of the home should be removed as a matter of property and person safety.
Inspecting your trees periodically for damage and visible changes is advised. Start a the bottom and work your way up, looking for signs of decay. Follow the trunk all the way up to the canopy noting any dead branches or twigs along the way.
Following these steps can help you prevent person and property damage from dead and decaying trees.
As always, I hope you took some value from this post and if you have any home related questions, please let me know at the email address below.
-AZ
Aaron M. Zuehlke is the owner and a Certified Master Inspector® at Zuehlke Inspection Service, LLC, a full-service home inspection company serving Southern Wisconsin. Specializing in Home inspection, Radon Testing, Mold Testing/inspection, Well Inspections/Well Water Testing, Residential Thermal Imaging, and Manufactured Home Foundation Certifications. He also manages several rental properties through Zuehlke Properties, LLC.