Root barriers have been in existence for many years. It is a defense system put into place to stop roots from getting too close to a home’s foundation.
Tree root damage to the foundation can result in thousands of dollars in repair costs to pavements, plumbing systems, and buildings.
If you have trees growing near your home, there is a possibility of tree root damage in the near future.
Luckily, with root barriers, getting rid of your trees doesn’t need to be an option. A root barrier that has been properly placed should help redirect or hold back root growth.
There are several different types of root barriers on the market that vary in design, depth, and thickness. Generally speaking, there are 3 root barrier types:
Types of Root Barriers
1. Chemical Inhibitors
This is where chemical growth agents or toxins are used to restrict the normal growth of roots. The chemicals and toxins include a geotextile fabric containing trifluralin, and a mixture of 1 quart of white acrylic paint and 3- and a half ounces of cupric carbonate.
These aren’t permanent solutions. They lose their effectiveness over a period of time. The rate of degradation is usually dependent on soil moisture conditions and soil temperature. In Florida, for example, the speed of degradation is much quicker than in other parts of the country.
2. Deflector Barriers
Root deflectors can be made from various materials. For instance, solid, metal, and wood. These materials help block or redirect roots to prevent them from growing in a particular area.
Deflector barriers are most effective in blocking small roots or shallow roots. Thicker root barriers which are easier to install (more than 2/3 inches) can block more aggressive roots.
When installing these barriers, it’s paramount that you allow for drainage. Leave at least 8 inches between the top of the layer of groundwater and the bottom of the barrier. This should help prevent the roots from developing fungal diseases.
3. Root Screens/Traps
These are made of woven fabrics, welded fiber sheets, and screens. They should be strong enough to girdle or strangle the roots as they grow and enlarge. They should be large enough to allow the tips of roots to grow through.
Effective materials include nylon fabrics with 1/26-inch openings and copper screen with 1/16-inch openings.
What researchers have to say
Various researches on the efficacy of root barriers have been conducted in the last fifteen years. Many of which focused on studying root barrier effects in structural damage prevention.
A Dutch study, for example, that looked at sixteen dissimilar root barriers treatments concluded that roots fled root barriers in each of the sixteen cases. The study also found that the roots ultimately grew back to the surface of the soil.
All plants, including trees, require oxygen to survive. It’s for this reason that research found that root growth occurred near the soil surface. In conclusion, the Dutch research found that for root barriers to be effective, the barriers need to protrude above the ground level and extend below the likely rooting depth.
Dr. Ed Gilman and Dr. Tom Smiley also conducted research on root barriers and published their results. Dr. Ed Gilman 1990’s research concluded that digging a trench for the installation of a root barrier made it easier for roots to grow downward and beneath the root barrier.
Dr. Tom Smiley, on his part, found that all roots that came back to the surface tended to be smaller in diameter.
What we can learn from studies involving Root Barriers
Root barriers are effective in minimizing structural damage from offending roots. The deeper the barrier is, the better the results. According to research, root barriers work better for sidewalks than driveways, but this is mostly dependent on how the installation is done.
Conclusion and Recommendation
1. Consider pruning roots
Root barriers work best for new tree plantings, where existing root structures won’t have to be cut. If you are to install a root barrier on an existing tree, you need to prune some roots as well.
Avoid cutting roots that are too close to the trunk of the tree. This can jeopardize the stability of the tree. Even if the stability of it isn’t compromised by cutting the roots, root pruning may still damage the health of the tree. It may cause the upper branches to die, cause sparse foliage, and ultimately cause the tree to die.
2. Use clean gravel beneath sidewalks
Research found that using clean gravel beneath sidewalks can help inhibit root growth.
3. Install the root barriers above grade
When installing the root barrier, ensure that the root barrier protrudes upwards by a few inches. This may help prevent roots from growing over the root barrier.
When carrying out landscape maintenance make sure not to break the top edge of the barrier.
4. Consider installing a deeper root barrier
The reason is simple – it’s simply more effective. It’ll provide more protection for much longer. Choose a root barrier that is more than 30 inches deep. Essentially, the deeper it is, the better it’ll be at stopping the growth of roots.
There you have it. Everything you need to know about root barriers and how they can work to protect your home from potential damage. Your home is probably the single most important investment you have. It only makes sense to protect it!