How to Prevent Trees from Damaging Pavement
Tree roots grow fast, and they can travel much farther under the soil than you might expect. While some roots grow deep underground, others grow very close to, or right on top of, the surface of the soil. This can cause all kinds of chaos. Tree roots are strong enough to cause cracks and damage to pavement. This can make paved areas unsightly, introduce potential hazards, and reduce property values. The good news is, there are several things you can do to prevent this from happening and keep your property beautiful.
Protect your paved areas from tree root damage by taking proper precautions when you’re planting trees and/or creating paved areas around your property.
If you don't want tree roots to damage your pavement, start by not planting trees anywhere near your paved areas. Or, don't put pavement near your trees! Ideally, there should be at least 10 feet of space between the trunk of the tree and any pavement, and 20 feet is even better. Remember, roots can spread to over three times the diameter of the tree's crown. Root systems can grow deep and far, and can cause trouble in pavement, plumbing, and structures both below and above the ground.
Trees growing directly alongside paved areas pose a high potential for disruption in the long run, and it's much harder to fix the damage later than it is to avoid it happening in the first place. If you do decide to plant trees near a hard walking surface, do some research first and avoid selecting fast growing varietals.
Water the Right Way
Encourage trees that can potentially affect your paved areas to grow deep roots by watering once every other week, deeply soaking the soil around the trees instead of saturating only the top layer. Set a sprinkler hose by the trunk you're watering, and let it run for at least two hours. Watering deeply and infrequently encourages the roots to grow deep under the soil, where they're less likely to damage to your property's surface.
Create a Root Barrier
If you want to really be on the safe side, contain tree roots with a barrier. To place the root barrier, dig a trench between the tree and the paved areas you want to protect. The trench should be 12 to 24 inches deep and at least 5 feet wide, where possible. Line the trench with special landscaping fabric or plastic that will prevent root growth. Some barriers are completely impassable, while others will allow some parts of roots to permeate, but prevent robust growth. Thick roots may grow under and around the barrier, but when it's installed correctly they won't grow through it.
Root barriers can be a great solution if your trees are far apart but not placed very strategically. This method makes the most sense early on in a landscaping or construction process, though, since it's not a great solution for areas with large, existing trees. Any exposed root systems near trenches under construction are likely to be damaged in the digging process, and those injuries can affect foliage growth and density, or expose your trees to potential infection from various pathogens
If you haven't yet created the paved area of concern, install it with tree roots in mind. Add a layer of gravel right below the pavement to reduce the chance that tree roots will damage your paved area. When the concrete is poured or the pavers are being placed, choose a design that's at least 4 inches thick. Using thicker concrete or heavier pavers makes it much harder for tree roots to break through.
Preventing Tree Root Destruction
Keep tree roots from destroying your pavement by taking all possible steps to prevent tree root destruction. Once the damage is done, you’ll have to take much more serious steps to fix the problem and keep the roots from creating even more chaos on your property.