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Vegetation Proximity to

Proximity of Vegetation To A Building


Richard Acree

When HABITEC Home and Building Inspections, LLC, conducts Home or Building Inspection in Nashville or Middle Tennessee, inspection of the vegetation at the exterior or the building is one of the components of the inspection. Vegetation in close proximity to a home or building can have a negative impact on the structure. The negative impact can include mechanical damage, limited access, mold, structural damage, and infestation from insects, rodents and/or reptiles. Sometimes the effect of the vegetation is not so subtle, as in the picture below.

Other times vegetation in close proximity can seem more insignificant, as in the picture below.

Often times homeowners can actually prefer vegetation close to or touching the building because they think it gives a quaint setting or special look. HABITEC Home and Building Inspections, LLC, understands the urge to pursue cosmetic appeal but disagrees with the concept of allowing vegetation to be in touch with the building. In fact, HABITEC recommends at least 18" spacing between any vegetation and the exterior of the building, and that trees not be allowed to overhang the building. I'll explain why as we go.

The 18" rule is a HABITEC rule, not one offered by State Rules or a building code. Other Inspectors may use a different number, or set of measurements. The point is that vegetation should not be allowed in contact with the structure, and that using a guide of 18" will provide a pad so that when the wind blows the vegetation does not reach over and hit the building anyway, at least not most of the time. In the picture below it is easy to imagine a gentle wind blowing these tree limbs back and forth and the limbs just continuing to beat the heck our of the house. Remember, a house is not designed or built to withstand that kind of impact.

The damage that could occur in the pic above is called mechanical damage. Mechanical damage is when the vegetation actually damages the building because it touches the building. The action of the wind moving the limbs back and forth can cause the damage. The larger the branches the larger the potential damage. See the photo below.

Trees that overhang a roof can have a significant impact on the building. This impact can include depositing leaves into gutters until the gutter is clogged and defective and depositing debris on the roof that creates a condition conducive for mold growth. The photo below is of a tree overhanging an apartment building.

Trees near or overhanging the roof can deposit enough leaves to render the roof drainage system defective. See the picture below.

The picture below is of a gutter system that is full of leaf debris and water. Obviously this water has no place to go and will just overflow when the next rain comes.

Filled gutters can be quickly overrun as in the picture below taken during a rain storm.

Water management systems such as the gutter/downspout/extension system that are filled with debris may not work well or at all. Failure of water management systems is the most common discrepancy found on home and commercial building inspections. Water that overflows a gutter can drop to the foundation wall at the base of the building and weaken the foundation, or the water can penetrate the crawl space or basement and create an environment conducive for mold growth. Overflowing gutters can also cause structural damage to the fascia and soffits that make up the eaves, as in the photo below.

Overflowing gutters can also backflow into the attic area and damage the wood that makes up the roof including the roof truss and decking. See the photo below. In this photo you are looking at the back side of fascia from inside the attic. The fascia has been damaged by water from overflowing gutters.

Vegetation in contact with a structure can cause structural damage in different ways. From the discussion above we now know one form of structural damage is caused by mechanical damage and another form can be caused by overflowing gutters in a failed water management system. But structural damage can also be caused by moisture in the vegetation that is held against the building. Now lets talk about that.

Although the exterior of buildings is expected to get wet when it rains, it is also expected to dry out in a reasonable time when the rain stops. In the picture below mechanical damage may occur from these shrubs touching the building but a more significant threat is the effect of moisture held against the building. Shrubs are not as powerful as trees when it comes to mechanical damage but shrubs can hold more water in the leaves and branches for a longer period of time because shrubs are usually thicker than trees.

Moisture held against the building by shrubs keeps the building wet. A wet building is more likely to allow water inside the building which can damage structural components and/or create an environment conducive for mold growth.

Another issue with shrubs and trees touching the building is that insects, rodents, reptiles and small animals, like raccoons, can use this vegetation as a path into the building via the attic. See the picture below of a black widow spider in an attic.

Another problem with vegetation in touch with or overhanging the building is the potential for mold. Mold can form from debris deposited on the roof by a tree overhanging the house. See the photo below. This fungal growth was caused by deposits on the roof from an overhanging evergreen tree.

Sometimes attic mold can start at the exterior on the roof as shown above. Deposits of tree debris on the roof can create fungal growth that can actually work its way inside the roof to the attic and create a mold growth there. See the photo below.

In the photo above the decking supporting the roof has mold growth present. This mold growth may have started because of the mold on the exterior of the roof that was shown in the previous picture.

Another issue with vegetation proximity to buildings involves limited access. Vegetation that is allowed to grow where normally people need to walk can inhibit normal access. Such is the case when ivy is allowed to grown on the railing of a deck staircase. Few people are willing to stick their hand inside the ivy as they walk up or down the stairs, thereby impeding this safety feature of the steps.

Another issue with vegetation is the proximity to utilities. The issue in the picture below is usually limiting access for utility workers and technicians so they can read or service the gas meter.

Likewise vegetation in front of the electrical panel inhibits the accessibility of the service technician and meter reader in the pictures below.

In fact the vegetation can be so close as to interfere with opening the panel as in the photo below.

However, it is possible for vegetation to interfere with the operation of utilities, especially HVAC components. If the vegetation impacts the cooling vents the unit has a difficult time with the cooling function.

So bottom line, keep vegetation at least 18" away from the structure and do not allow the trees to overhang the house.

Thank you,

Richard Acree

Comments in this article are the copyrighted intellectual property of Richard Acree, President, HABITEC Home and Building Inspections, LLC, and contributing members of the Active Rain Real Estate network, and are intended to educate and otherwise assist home owners, sellers and buyers, building owners, sellers and buyers, realtors, real estate investors, property managers, and lenders in the process of owning, buying or selling homes or commercial buildings. HABITEC is a residential (home) and commercial building inspection company serving Middle Tennessee including Nashville, Brentwood, Franklin, Murfreesboro, Smyrna, Mt. Juliet, Hendersonville, Dickson, Belle Meade, Columbia, Spring Hill and more! In addition to building inspections HABITEC offers Environmental Services for mold assessments, radon testing and water quality analysis. Additional information about HABITEC can be found on our website at, or call 615-376-2753.

Richard Acree is the author of the HABITEC Home and Building Inspections ActiveRain Blog and founder of the ActiveRain Group Tennessee Home and Building Inspectors. All are welcome to join and see more blogs like this one. You can also join HABITEC on Facebook or Linked .

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