A low wall that cracks or a fence that leans due to underground roots: it is a classic scenario. Does this mean you have to cut down the tree responsible or redo the entire installation? Not necessarily. At Districlos, we often encounter this problem. Here is how to protect your fence while keeping your trees alive.
Identifying the source of the damage
Before digging, look at how the structure is reacting. Flexible mesh fencing that sags or posts that lean indicate that roots are spreading just below the surface. This is a common phenomenon with poplars, cedars, or willows, whose creeping roots can lift entire concrete blocks.
The intervention will depend on the damage. A slightly deviated post is easily straightened. On the other hand, a low wall cracked along its entire length will require the foundations to be reviewed.
What the law says
If the roots responsible come from the neighboring land, Article 673 of the Civil Code is clear: you have the right to cut them at the boundary of your property. However, in practice, talk to your neighbor first. Uncontrolled cutting can kill the tree and lead to legal trouble.
In the case of a shared fence, repair costs are generally split in two. Also remember to check planting distances (often 2 meters for large trees): this is a strong argument if the planting does not comply with regulations.
Cutting roots (with caution)
Cutting roots is not a trivial matter. You risk weakening the tree against the wind or causing it to die. Avoid touching structural roots (the thickest ones, near the trunk) without asking an arborist for advice, and use disinfected tools to make clean cuts.
Once the path is cleared, do not simply pour concrete directly onto the remaining roots. The vegetation will quickly reclaim its space and the pressure will return the following year. Instead, plan for a buffer zone.
Installing a root barrier
To permanently block progression, a root barrier remains the most reliable option. It is a rigid membrane, often made of high-density polyethylene (HDPE), which is buried vertically between the tree and the foundations. Instead of growing horizontally, the roots are forced to go down.
Installation is simple:
- Dig a trench about 60 cm deep along the area to be protected.
- Slide the membrane in vertically, letting it protrude a few centimeters above the ground.
- Refill with well-compacted soil.
Adapting the type of fence
Sometimes, it is better to adapt rather than to fight. If the ground is saturated with roots, avoid digging. If you already have a low wall in good condition, simply install your posts on base plates.
Keep in mind that a rigid panel will not handle ground deformation well. In high-risk areas, chain-link fencing will be much more forgiving of slight ground movements. You can also simply shift the line of your fence to go around the stump.
If you absolutely must maintain the exact layout, the base will need to be reinforced. The combination of notched posts and concrete gravel boards handles ground pressure very well.
Every plot of land has its own constraints. If you are unsure about which equipment to use, contact our Districlos advisors: we will help you find the right configuration to block vegetation without spoiling the aesthetics of your garden.
Expert in fencing, gates, and outdoor landscaping since 2019.
Holds a Master’s degree in Digital Marketing – SEO, UX/UI.
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