Nobody hates trees, right? Certainly not us! However, tree roots can be a major cause of asphalt pavement damage. Good thing we have known methods of preventing tree root damage before it can get worse!
Trees add beauty and value to your property. They also provide shade and keep the air fresh and clean, especially during hot summer months. Having trees of varying sizes and types lined along your driveway or interspersed among the stalls in your parking lot make everything appear vibrant and healthy. On the other hand, large trees have wide root systems that can ultimately wreak havoc on any paved surface near them.
Here are 4 methods that can help prevent tree root damage to your asphalt pavement:
1. Cut away small roots
Small roots spread wider and grow faster than their larger counterparts. Once you see slight bumps on the surface of your asphalt pavement, chances are, the tree roots are already spreading further and are beginning to push up against the asphalt layer. If not kept in check in a timely manner, the asphalt will ultimately break and form cracks or sinkholes in the long run. It is best to take action before things worsen.
Using the appropriate type of gas-powered or electric asphalt saw with a diamond blade (available at local tool rentals), cut away the damaged asphalt. If the damage is very wide, work in sections so you don’t end up having bare patches of root-infested soil all over your property.
Clean the surface so there are no debris or small pebbles where the saw blade can get caught. Stone fragments can deform or damage the blade, and cause potential accidents to the saw operator. Mark the sections of the asphalt that you need to cut so you always have a guide. Once you start cutting, make a square cut and widen the area slightly beyond the actual damaged portion of asphalt to get a solid, clean cut. Remember to lift the blade completely off the asphalt surface and turn the engine off before shifting directions. Turning while the blade is still in the cut can break the saw blade or even cause accidents.
Once the asphalt is completely cut, remove the damaged pavement and cut away the small roots. Install a root barrier (as suggested below) to coax new roots to grow away from your asphalt pavement. Clean the exposed area and fill with permanent asphalt patch. Tamp down until compacted using either a handheld tamping tool or a vibrating plate compactor.
Alternatively, if you are a professional contractor, you can use an infrared asphalt heater instead of cutting away the pavement. Just place the machine over the damaged area and turn it on. Wait a few minutes until the asphalt is heated back to mixing consistency. Use a shovel to transfer the softened asphalt into a hotbox and clear then off the tree roots. Once that’s done, pour the heated asphalt back into place and compress with a vibrating plate compactor for an even finish.
2. Set up a physical root barrier
Root barriers are solutions meant to intentionally redirect root growth. They can either be in chemical or solid form, such as metal, fiberglass, or high-density polyethylene HDPE). We recommend that you use a solid root barrier instead of the chemical version. Root barriers are best installed when a tree is newly planted. However, since this is not always the case, you can put it up when repairing your pavement. To install the barrier, dig down vertically and set it around the tree. Make sure that the open end (depending on the barrier type) faces away from the direction of the pavement you are protecting. This will guide the roots to grow down and away from your driveway or parking slots. Alternatively, the root barrier can also be installed like an underground “wall” if you are trying to protect the full length of your driveway or wide sections of the parking area (in parking facilities).
3. Avoid cutting large roots
Although this topic is all about root-cutting, we do not recommend removing large roots, as they serve as support and prop the tree upright. Removal of large roots can weaken the tree and eventually cause it to die and topple over, especially during heavy winds and rain. This can be dangerous for both vehicle and human traffic. Setting up a root barrier is a more practical option in this scenario, as it helps to coax roots away from your pavement.
4. Contact a professional arborist for advice
If you feel that you are not confident enough to carry out the task of removing tree roots, or if you are unsure which tree is actually causing the damage to your asphalt, we recommend that you contact a professional arborist. An arborist should be able to identify the trees in your property and provide you with advice and insight on the best course of action.
Having trees in and around your property can be highly advantageous, but you must also plan where they should be planted to avoid future problems. In cases where your lot already has matured trees growing on it, we recommend that you design your driveway or parking spaces in such a way that they veer away from the trees, and still conform to an aesthetically pleasing layout.