Trees and your home: Trees can add shade, privacy, beauty, and value to a property. But when you’re buying a home, they can also raise some important questions.
Is that large tree close to the house damaging the foundation? Can roots get into the sewer line? Should branches be touching or hanging over the roof? And how can you tell whether a mature tree is healthy or potentially hazardous?
We recently discussed these questions on the Real Estate Red Flags podcast with Josh, an ISA Certified Arborist. While trees themselves are generally outside the scope of a standard home inspection, the effects trees can have on a home are something inspectors encounter regularly.
Are Trees Part of a Home Inspection?
Generally, no. A home inspection is an inspection of the home and its systems, not an evaluation of the health or structural condition of the trees on the property.
However, trees can affect the home.
During an inspection, we may identify conditions such as branches contacting the roof or structure, tree debris accumulating in gutters or around solar panels, roots affecting walkways or other improvements, or visible conditions that suggest a tree may warrant further evaluation.
If a large tree appears dead, unhealthy, or potentially hazardous, particularly when it’s close enough to damage the home if it falls, we may recommend having it evaluated by a qualified arborist.
Can Tree Roots Damage a Foundation?
This may be the most common tree-related question we receive during home inspections.
A buyer sees a large tree growing near the house and immediately wonders: Are those roots damaging the foundation?
Interestingly, during our inspections in Southern California, we don’t commonly find visible evidence of foundation damage that can clearly be attributed to tree roots.
Josh explained one reason why.
“The roots want to go where water is. And the foundation is not water, obviously. So the roots do not want to grow into the foundation. They really want to grow away from it.”
He explained that when roots growing toward a foundation encounter it, they will often redirect rather than attempt to grow through it.
That doesn’t mean tree roots can never contribute to problems. Josh noted that situations can become more concerning when a tree has been planted in an area that simply doesn’t provide adequate space for the species as it matures.
That is one reason proper tree selection and placement are so important.
As Josh put it:
“Get the right species. Make sure the tree basin is large enough for that species at maturity.”
For a home buyer, the presence of a large tree near a house shouldn’t automatically be interpreted as evidence of foundation damage. The foundation itself needs to be evaluated for visible signs of movement or damage, and concerns about the tree should be evaluated by an arborist when appropriate.
Tree Roots and Sewer Lines
Sewer pipes are a different story.
Tree roots are naturally attracted to moisture, and older sewer lines can provide opportunities for roots to enter.
This is something we regularly encounter during sewer scope inspections.
Older clay sewer lines contain numerous joints. Cast-iron lines can develop corrosion and deterioration. Roots can take advantage of small openings and eventually grow into the pipe.
Once inside, roots can become increasingly dense and interfere with the flow through the sewer line. In more severe situations, root intrusion may be associated with significant deterioration or damage to the pipe.
Josh explained the basic reason:
“Roots, they’re always looking for water. They’re always looking for water and if they can sense water anywhere they will grow towards it.”
This is one reason a sewer scope can be an important addition to a home inspection, particularly when purchasing an older home or a property with mature trees.
The location of a tree alone cannot tell you what’s happening inside an underground sewer pipe. A sewer camera can.
Trees Touching or Overhanging the Roof
Trees don’t have to be underground to cause problems.
Branches touching a house can damage roofing, siding, windows and other exterior components. We’ve inspected homes where tree branches had rubbed directly against roof shingles long enough to damage or remove portions of the shingles.
That’s particularly frustrating when the roof itself is relatively new.
Roofing materials are designed as a system. When branches repeatedly rub against the roof, particularly as they move in the wind, they can damage the exterior roof covering and expose the materials beneath it to deterioration and eventually moisture intrusion.
Even branches that aren’t currently touching the roof may warrant attention if they’re close enough to contact it during windy conditions.
From an arborist’s perspective, Josh recommends maintaining clearance:
“You basically never want any part of a tree touching any part of your house.”
Trees overhanging roofs can also contribute leaves and other debris to gutters and roof surfaces. Homes with solar panels can develop accumulations of leaves and debris beneath the panels, potentially creating attractive areas for birds and rodents to nest.
What About a Tree That Looks Dangerous?
A home inspector is not an arborist.
If we see a large tree that appears dead, significantly distressed, or positioned in a way that raises concerns about the house, we’ll generally recommend further evaluation rather than attempting to diagnose the tree ourselves.
Even something as seemingly straightforward as a leaning tree isn’t necessarily straightforward.
Josh explained that arborists look at whether a tree has what is called a corrected lean—where the tree initially grew at an angle but subsequently began growing more vertically. That can be very different from a tree continuing to lean in one direction without correction.
He also considers what would happen if the tree or a major limb failed. Is it within striking distance of the house? A driveway? An area where children play?
Those are questions for someone trained to evaluate trees.
The Home Inspector and Arborist Have Different Jobs
Trees are a good example of why buying a home can sometimes require more than one type of professional.
The home inspector evaluates the house and identifies visible conditions affecting the home. A sewer scope allows us to see what’s happening inside the property’s sewer line. An arborist has specialized training to evaluate the health, condition, and potential hazards associated with trees.
When those areas overlap, each professional brings a different perspective.
For much more about trees, home inspections, roots, roofs, sewer lines, tree health and when to call an arborist, watch our full conversation with Josh on the Real Estate Red Flags podcast below.
Book your home inspection by calling 818-298-3405 or book online here.
For a tree inspection or arborist services, contact Josh treecheck.io or email him at: josh@treecheck.io