Public enemy number one in the foundation repair industry is low moisture content in soils. Nothing pulls more water out of the soil than the tree. Almost every home has one, some HOAs even require them, and yet the continue to cause the most damage to the foundation. A root barrier could be the solution.
Roots from trees reach much further than people might suspect, up to 2-3 times the height of the tree. Often times where there are cracks, there is a tree nearby. Therefore we will typically recommend that trees with roots that can reach the foundation should either be removed or a root barrier installed.
Protect the house and the tree with a root barrier.
People love their trees. They add value to the property and shade to the house during the summer months. However when it comes down to it, the foundation needs to be protected. There is an option to install a root barrier in between the tree and the house. This allows you to severe the roots under the house without losing the tree. The tabs below will show you our process for installing one.
Trees come in all shapes, sizes and root systems. Most common types of trees will have roots that can suck water out of the soil below or near the foundation that will compromise the support.
When installing a root barrier it’s important to place the trench at least 3 times the circumference away from tree to give the tree the best chance of survival. If a tree is close enough to the house where that distance can’t be met, then one should consider removing the tree completely, but many other factors play into that decision like the ago and size. You should talk to a tree expert to determine if that is the best solution.
Once we know where the barrier will go, it’s time to dig the trench.
The trench is the messiest part of the installation. A hand dug trench is dug in between the tree and the house at the previously mentioned distance. The hand digging is recommended so that any irrigation or utility lines can be navigated around.
Typically the surface roots from trees, which is the root system that drink the most water from the soils around the foundation, are located near the surface 0-18 inches below the surface. Therefore we dig our trench with a depth of 30 inches to make sure all those roots are accounted for. As we dig the trench any and all roots are severed from the tree.
Once the trench is dug and roots severed, the barrier is placed within the trench.
The goal of the barrier is to prevent new roots from moving closer towards the foundation. If working as intended the roots will hit the barrier and turn in another direction away from the barrier. Therefore it’s important to use a barrier that is thick enough to prevent penetration and strong enough so that it doesn’t allow gaps.
Concrete will crack over time and steel is super expensive. A thick high density polyethylene plastic will be flexible enough to move with the soil and strong enough to disallow the penetrating roots. We use a 30 inch deep, 30 mil thick HDPE barrier. It’s a single sheet of plastic so there are no gaps. This is the recommended thickness, but a lot of companies might use something thinner as it is cheaper and easier to acquire. We have little faith anything thinner will work in the long run.
Once the barrier is placed in the trench, the dirt is filled back in and compacted. This section of the foundation is now protected from the tree!